Editing Conditions comorbid to autism

{{Short description|Medical conditions more common in autistic people}}
[[Autism spectrum disorder]] (ASD) or simply '''autism''' is a [[neurodevelopmental disorder]] that begins in early childhood, persists throughout adulthood, and is characterized by difficulties in social communication and restricted, repetitive patterns of behavior.<ref name=":9">{{Cite book |last=[[American Psychiatric Association]] |title=[[Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision]] |publisher=American Psychiatric Association |year=2022 |isbn=978-0-89042-575-6 |location=Washington, DC |doi=10.1176/appi.books.9780890425787 |s2cid=249488050}}</ref> There are many '''conditions comorbid to autism''', such as [[attention deficit hyperactivity disorder]], [[anxiety disorder]]s, and [[epilepsy]].

In medicine, [[comorbidity]] is the presence of one or more additional conditions co-occurring with the primary one, or the effect of such additional disorders. Distinguishing between ASD and other diagnoses can be challenging because the traits of ASD often overlap with symptoms of other disorders, and the characteristics of ASD make traditional diagnostic procedures difficult.<ref name="IntHandbook">{{cite book |url=https://archive.org/details/internationalhan00mats |title=International Handbook of Autism and Pervasive Developmental Disorders |publisher=Springer |year=2011 |editor1=Johnny L. Matson |location=New York |pages=[https://archive.org/details/internationalhan00mats/page/n78 53]–74 |editor2=Peter Sturmey |url-access=limited}}</ref><ref>{{cite journal |vauthors=Underwood L, McCarthy J, Tsakanikos E |date=September 2010 |title=Mental health of adults with autism spectrum disorders and intellectual disability |journal=Current Opinion in Psychiatry |type=Review |volume=23 |issue=5 |pages=421–426 |doi=10.1097/YCO.0b013e32833cfc18 |pmid=20613532 |s2cid=13735841}}</ref>

Autism is associated with several [[genetic disorder]]s,<ref name="Zafeiriou">{{cite journal |vauthors=Zafeiriou DI, Ververi A, Vargiami E |date=June 2007 |title=Childhood autism and associated comorbidities |journal=Brain & Development |type=Review |volume=29 |issue=5 |pages=257–272 |doi=10.1016/j.braindev.2006.09.003 |pmid=17084999 |s2cid=16386209}}</ref> perhaps due to an overlap in genetic causes.<ref>{{cite web |date=March 1, 2013 |title=Overlap Blurs Diagnostic Categories – NIH-funded Study |url=http://www.nimh.nih.gov/news/science-news/2013/five-major-mental-disorders-share-genetic-roots.shtml |url-status=dead |archive-url=https://web.archive.org/web/20150510014204/http://www.nimh.nih.gov/news/science-news/2013/five-major-mental-disorders-share-genetic-roots.shtml |archive-date=May 10, 2015 |access-date=May 26, 2015 |publisher=NIMH |quote=National Institutes of Health-funded researchers discovered that people with disorders traditionally thought to be distinct – autism, ADHD, bipolar disorder, major depression and schizophrenia – were more likely to have suspect genetic variation at the same four chromosomal sites. These included risk versions of two genes that regulate the flow of calcium into cells. |vauthors=Cuthbert B}}</ref> About 10–15% of autism cases have an identifiable [[Mendelian inheritance|Mendelian]] (single-gene) condition, [[chromosome abnormality]], or other genetic syndrome,<ref name="Folstein">{{cite journal | vauthors = Folstein SE, Rosen-Sheidley B | title = Genetics of autism: complex aetiology for a heterogeneous disorder | journal = Nature Reviews. Genetics | volume = 2 | issue = 12 | pages = 943–955 | date = December 2001 | pmid = 11733747 | doi = 10.1038/35103559 | s2cid = 9331084 }}</ref> a category referred to as [[syndromic autism]].

Approximately 8 in 10 people with autism suffer from a mental health problem in their lifetime, in comparison to 1 in 4 of the general population that suffers from a mental health problem in their lifetimes.<ref name="Autistica, 1"/><ref name="Autistica, 2"/><ref name="JADD"/>
[[File:Overlapping clinical phenotypes in genes associated with monogenic forms of autism spectrum disorder (ASD), dystonia, epilepsy and schizophrenia.svg|thumb|[[Euler diagram]] showing overlapping [[Clinical phenotype|clinical phenotypes]] in genes associated with [[monogenic disease|monogenic forms]] of [[autism spectrum disorder]] (ASD), [[dystonia]], [[epilepsy]] and [[schizophrenia]]:
{{legend|#007fff|Genes associated with epilepsy}}
{{legend|#007f7f|Genes associated with schizophrenia}}
{{legend|#d4aaff|Genes associated with autism spectrum disorder}}
{{legend|#ff0000|Genes associated with dystonia}}]]

==Comorbid conditions==

===Anxiety===
[[Anxiety disorder]]s are common among children and adults with ASD.  Symptoms are likely affected by age, level of cognitive functioning, degree of social impairment, and ASD-specific difficulties. Many anxiety disorders, such as [[social anxiety disorder]] and [[generalized anxiety disorder]], are not commonly diagnosed in people with ASD because such symptoms are better explained by ASD itself, and it is often difficult to tell whether symptoms such as compulsive checking are part of ASD or a co-occurring anxiety problem. The prevalence of anxiety disorders in children with ASD has been reported to be anywhere between 11% and 84%; the wide range is likely due to differences in the ways the studies were conducted.<ref name="White SW, Oswald D, Ollendick T, Scahill L 2009 216–29">{{cite journal | vauthors = White SW, Oswald D, Ollendick T, Scahill L | title = Anxiety in children and adolescents with autism spectrum disorders | journal = Clinical Psychology Review | volume = 29 | issue = 3 | pages = 216–229 | date = April 2009 | pmid = 19223098 | pmc = 2692135 | doi = 10.1016/j.cpr.2009.01.003 }}</ref>

A [[systematic review]] summarized available evidence on interventions to reduce anxiety in school children with autism spectrum disorder. Of the 24 studies reviewed, 22 used a [[cognitive behavioral therapy]] (CBT) approach. The review found that CBT was moderately to highly effective at reducing anxiety in school children with autism spectrum disorder, but that effects varied depending on whether they were reported by clinicians, parents or self-reported. Treatments involving parents and one-on-one compared to group treatments were more effective.<ref>{{cite journal | vauthors = Hillman K, Dix K, Ahmed K, Lietz P, Trevitt J, O'Grady E, Uljarević M, Vivanti G, Hedley D | display-authors = 6 | title = Interventions for anxiety in mainstream school-aged children with autism spectrum disorder: A systematic review | journal = Campbell Systematic Reviews | volume = 16 | issue = 2 | pages = e1086 | date = June 2020 | pmid = 37131419 | pmc = 8356281 | doi = 10.1002/cl2.1086 | s2cid = 218953088 }}</ref>

===Attention deficit hyperactivity disorder===
The diagnosis manual [[DSM-IV]] did not allow the co-diagnosis of ASD and [[attention deficit hyperactivity disorder]] (ADHD). However, following years of clinical research, the [[DSM-5]] released in 2013 removed this prohibition of co-morbidity. Thus, individuals with autism spectrum disorder may also have a diagnosis of ADHD, with the modifiers of a predominantly inattentive, hyperactive, combined, or not otherwise specified presentation. Clinically significant symptoms of these two conditions commonly co-occur, and children with both sets of symptoms may respond poorly to standard ADHD treatments. Individuals with autism spectrum disorder may benefit from additional types of medications.<ref>{{cite journal | vauthors = Reiersen AM, Todd RD | title = Co-occurrence of ADHD and autism spectrum disorders: phenomenology and treatment | journal = Expert Review of Neurotherapeutics | volume = 8 | issue = 4 | pages = 657–669 | date = April 2008 | pmid = 18416666 | doi = 10.1586/14737175.8.4.657 | s2cid = 1582890 }}</ref><ref>[http://www.dsm5.org/Documents/ADHD%20Fact%20Sheet.pdf DSM 5 ADHD Fact Sheet] {{webarchive |url=https://web.archive.org/web/20150811064504/http://www.dsm5.org/Documents/ADHD%20Fact%20Sheet.pdf |date=August 11, 2015 }}
</ref> The term '''''AuDHD''''' is sometimes used for those with both autism and ADHD.<ref>{{cite web |last1=Newberry |first1=Laura |title=Autism and ADHD often go hand-in-hand. What's it like to have 'AuDHD'? |url=https://www.latimes.com/california/newsletter/2023-04-25/adhd-and-autism-group-therapy |website=Los Angeles Times |date=25 April 2023 |access-date=18 February 2024 |archive-date=2024-04-05 |archive-url=https://web.archive.org/web/20240405234700/https://www.latimes.com/california/newsletter/2023-04-25/adhd-and-autism-group-therapy |url-status=live }}</ref><ref>{{cite web |title=AuDHD (Autism + ADHD) Resources |url=https://neurodivergentcounselling.ca/resources/audhd-resources/ |website=Neurodivergent Counselling Services |date=3 October 2021 |access-date=18 February 2024 |archive-date=18 February 2024 |archive-url=https://web.archive.org/web/20240218124852/https://neurodivergentcounselling.ca/resources/audhd-resources/ |url-status=live }}</ref> There are also studies suggesting noticeable differences in presenting symptoms by gender which can complicate diagnosis, especially in adulthood.<ref>{{cite web |title=Exploring the gendered implications of an adulthood AuDHD diagnosis |url=https://www.open-access.bcu.ac.uk/15499/1/QHR_final_accepted_version_190424.pdf |author=<!--Not stated--> |website=Birmingham City University |date=19 April 2024 |access-date=8 October 2024 }}</ref><ref>{{cite journal |title=Camouflage and masking behavior in adult autism |date=16 March 2023 |first1=Javad |first2=Arman |first3=Mahtab |last1=Alaghband-rad |last2=Hajikarim-Hamedani |last3=Motamed |journal=Frontiers in Psychiatry |volume=14 |doi=10.3389/fpsyt.2023.1108110 |doi-access=free |pmid=37009119 |pmc=10060524 }}</ref><ref>{{cite web |title=The Different Signs Of AuDHD In Women & Girls|url=https://augmentive.io/blog/signs-audhd-women-girls|website=Augmentive|first=Sarah|last=Norman|date=5 June 2024|access-date=8 October 2024 }}</ref>

===Avoidant/restrictive food intake disorder<span class="anchor" id="Avoidant/restrictive food intake disorder (ARFID)"></span> ===

[[Avoidant/restrictive food intake disorder]] (ARFID) is a feeding or [[eating disorder]] in which individuals significantly limit the volume or variety of foods they consume, causing [[malnutrition]], [[weight loss]], and [[psychosocial]] problems.<ref>{{Cite journal |last=Ramirez |first=Z |date=May 1, 2024 |title=Avoidant Restrictive Food Intake Disorder |url=https://www.ncbi.nlm.nih.gov/books/NBK603710/ |access-date=August 30, 2024 |website=NIH: National Library of Medicine |pmid=38753906}}</ref> A 2023 review concluded that "there is considerable overlap between ARFID and autism," finding that 8% to 55% of children diagnosed with ARFID were autistic.<ref>{{Cite journal |last=Keski-Rahkonen |first=A |date=November 1, 2023 |title=Avoidant-restrictive food intake disorder and autism: epidemiology, etiology, complications, treatment, and outcome |url=https://pubmed.ncbi.nlm.nih.gov/37781978/ |journal=Current Opinion in Psychology |volume=36 |issue=6 |pages=438–442 |doi=10.1097/YCO.0000000000000896 |pmid=37781978 |via=NIH: National Library of Medicine}}</ref> Unlike eating disorders such as [[anorexia nervosa]] and [[bulimia]], [[body image disturbance]] is not a root cause. Individuals with ARFID may have trouble eating due to the sensory characteristics of food (appearance, smell, texture, or taste); [[executive function]] disregulation; fears of choking or vomiting; low appetite; or a combination of these factors.<ref>{{Cite book |title=Diagnostic and Statistical Manual of Mental Disorders |date=2022 |publisher=American Psychiatric Association |isbn=978-0-89042-575-6 |edition=Fifth Edition, Text Revision |location=Washington DC |publication-date=2022 |pages=376–381}}</ref>

===Bipolar disorder===
[[Bipolar disorder]], or manic-depression, is itself often claimed to be comorbid with a number of conditions, including autism.<ref>{{cite journal | vauthors = McElroy SL | title = Diagnosing and treating comorbid (complicated) bipolar disorder | journal = The Journal of Clinical Psychiatry | volume = 65 | issue = Suppl 15 | pages = 35–44 | year = 2004 | pmid = 15554795 }}</ref> Autism includes some{{Which|date=May 2025}} symptoms commonly found in mood and anxiety disorders.<ref>{{cite journal | vauthors = Towbin KE, Pradella A, Gorrindo T, Pine DS, Leibenluft E | title = Autism spectrum traits in children with mood and anxiety disorders | journal = Journal of Child and Adolescent Psychopharmacology | volume = 15 | issue = 3 | pages = 452–464 | date = June 2005 | pmid = 16092910 | doi = 10.1089/cap.2005.15.452 | url = https://zenodo.org/record/1235253 | type = Submitted manuscript | access-date = 2018-09-11 | archive-date = 2020-08-18 | archive-url = https://web.archive.org/web/20200818105220/https://zenodo.org/record/1235253 | url-status = live }}</ref>

===Bowel disease===
Gastrointestinal symptoms are a common comorbidity in patients with autism spectrum disorders (ASD), even though the underlying mechanisms are largely unknown. The most common gastrointestinal symptoms reported by proprietary tool developed and administered by Mayer, Padua, and Tillisch (2014) are abdominal pain, constipation, diarrhea and bloating, reported in at least 25 percent of participants.<ref>{{cite journal | vauthors = Mayer EA, Padua D, Tillisch K | title = Altered brain-gut axis in autism: comorbidity or causative mechanisms? | journal = BioEssays | volume = 36 | issue = 10 | pages = 933–939 | date = October 2014 | pmid = 25145752 | doi = 10.1002/bies.201400075 | s2cid = 4608380 }}</ref> Carbohydrate digestion and transport is impaired in individuals with autism spectrum disorder, which is thought to be attributed to functional disturbances that cause increased [[intestinal permeability]], deficient enzyme activity of [[disaccharide]]s, increased [[secretin]]-induced pancreatico-biliary secretion, and abnormal fecal flora [[Clostridia]] taxa.<ref>{{cite journal | vauthors = Williams BL, Hornig M, Buie T, Bauman ML, Cho Paik M, Wick I, Bennett A, Jabado O, Hirschberg DL, Lipkin WI | display-authors = 6 | title = Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances | journal = PLOS ONE | volume = 6 | issue = 9 | pages = e24585 | date = 2011 | pmid = 21949732 | pmc = 3174969 | doi = 10.1371/journal.pone.0024585 | bibcode = 2011PLoSO...624585W | doi-access = free }}</ref> Altered gastrointestinal function accompanied by pain may induce feeding issues and increase perceived negative behaviors, including [[self injury]], in individuals with autism.<ref>{{cite web | url = https://www.focusforhealth.org/common-gi-disorders-in-autism | title = Common GI Disorders in Autism | website = Focus For Health | access-date = 2020-09-06 | archive-date = 2020-12-05 | archive-url = https://web.archive.org/web/20201205215616/https://www.focusforhealth.org/common-gi-disorders-in-autism/ | url-status = dead }}</ref>

=== Depression ===
[[Major depressive disorder]] has been shown by several studies to be one of the most common comorbid conditions in those with ASD,<ref>{{cite journal | vauthors = Stewart ME, Barnard L, Pearson J, Hasan R, O'Brien G | title = Presentation of depression in autism and Asperger syndrome: a review | journal = Autism | volume = 10 | issue = 1 | pages = 103–116 | date = January 2006 | pmid = 16522713 | doi = 10.1177/1362361306062013 | s2cid = 12014511 }}</ref><ref>{{cite journal | vauthors = Ghaziuddin M, Ghaziuddin N, Greden J | title = Depression in persons with autism: implications for research and clinical care | journal = Journal of Autism and Developmental Disorders | volume = 32 | issue = 4 | pages = 299–306 | date = August 2002 | pmid = 12199134 | doi = 10.1023/A:1016330802348 | publisher = Kluwer Academic Publishers-Plenum Publishers | hdl = 2027.42/44620 | s2cid = 38817077 | eissn = 1573-3432 | hdl-access = free }}</ref> and is thought to develop and occur more in high-functioning individuals during adolescence, when the individual develops greater insight into their differences from others.<ref name="MashBarkley2003" /> In addition, the presentation of depression in ASDs can depend on the level of cognitive functioning in the individual, with lower functioning children displaying more behavioral issues and higher functioning children displaying more traditional depressive symptoms.<ref name="IntHandbook" />

A 2019 meta-analysis identified autistic people as being four times more likely to have depression than non-autistic people,<ref>{{cite journal |last1=Hudson |first1=Chloe C. |last2=Hall |first2=Layla |last3=Harkness |first3=Kate L. |date=2019 |title=Prevalence of Depressive Disorders in Individuals with Autism Spectrum Disorder: a Meta-Analysis |url=https://pubmed.ncbi.nlm.nih.gov/29497980/ |journal=Journal of Abnormal Child Psychology |volume=47 |issue=1 |pages=165–175 |doi=10.1007/s10802-018-0402-1 |pmid=29497980 |access-date=23 January 2025}}</ref> with approximately 40% of autistic adults having depression.<ref>Hudson C.C. et al. J. Abnorm. Child Psychol. 47, 165–175 (2019) PubMed</ref>

===Developmental coordination disorder (dyspraxia)===
The initial accounts of [[Asperger syndrome]]<ref name=McPartland/> and other diagnostic schemes<ref>{{cite journal | vauthors = Ehlers S, Gillberg C | title = The epidemiology of Asperger syndrome. A total population study | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 34 | issue = 8 | pages = 1327–1350 | date = November 1993 | pmid = 8294522 | doi = 10.1111/j.1469-7610.1993.tb02094.x }} {{cite web|url=http://asperger.org/Publications/Ehlers_and_Gillberg_Article.asp |title=Truncated version |access-date=2008-06-15 |archive-url=https://web.archive.org/web/20080719235125/http://www.asperger.org/Publications/Ehlers_and_Gillberg_Article.asp |archive-date=2008-07-19 |url-status=dead }}</ref> include descriptions of [[developmental coordination disorder]]. Children with ASD may be delayed in acquiring motor skills that require motor dexterity, such as bicycle riding or opening a jar, and may appear awkward or "uncomfortable in their own skin". They may be poorly coordinated, or have an odd or bouncy gait or posture, [[Dysgraphia|poor handwriting, other hand/dexterity impairments]], or problems with visual-motor integration, visual-perceptual skills, and conceptual learning.<ref name=McPartland/><ref name=Klin>{{cite journal | vauthors = Klin A | title = [Autism and Asperger syndrome: an overview] | journal = Revista Brasileira de Psiquiatria | volume = 28 | issue = suppl 1 | pages = S3-11 | date = May 2006 | pmid = 16791390 | doi = 10.1590/S1516-44462006000500002 | doi-access = free }}</ref> They may show problems with [[proprioception]] (sensation of body position) on measures of developmental coordination disorder, balance, [[tandem gait]], and finger-thumb apposition.<ref name=McPartland>{{cite journal | vauthors = McPartland J, Klin A | title = Asperger's syndrome | journal = Adolescent Medicine Clinics | volume = 17 | issue = 3 | pages = 771–88; abstract xiii | date = October 2006 | pmid = 17030291 | doi = 10.1016/j.admecli.2006.06.010 | doi-broken-date = 1 November 2024 }}</ref>

===Epilepsy===
ASD is also associated with [[epilepsy]], with variations in risk of epilepsy due to age, cognitive level, and type of language disorder.<ref>{{cite journal | vauthors = Tuchman R, Rapin I | title = Epilepsy in autism | journal = The Lancet. Neurology | volume = 1 | issue = 6 | pages = 352–358 | date = October 2002 | pmid = 12849396 | doi = 10.1016/S1474-4422(02)00160-6 | s2cid = 34012901 }}</ref> One in four autistic children develops [[seizure]]s, often starting either in early childhood or adolescence.<ref>{{cite web | url=http://www.nimh.nih.gov/health/publications/a-parents-guide-to-autism-spectrum-disorder/index.shtml | title=A Parent's Guide to Autism Spectrum Disorder | publisher=[[National Institute of Mental Health]] | access-date=17 October 2013 | archive-date=23 February 2016 | archive-url=https://web.archive.org/web/20160223233600/http://www.nimh.nih.gov/health/publications/a-parents-guide-to-autism-spectrum-disorder/index.shtml | url-status=live }}</ref> Seizures, caused by abnormal electrical activity in the brain, can produce a temporary loss of consciousness (a "blackout"), a body convulsion, unusual movements, or staring spells. Sometimes a contributing factor is a lack of sleep or a high fever. An [[Electroencephalogram|EEG]] can help confirm the seizure's presence. Typically, onset of epilepsy occurs before age five or during puberty,<ref name=Canitano>{{cite journal | vauthors = Canitano R | title = Epilepsy in autism spectrum disorders | journal = European Child & Adolescent Psychiatry | volume = 16 | issue = 1 | pages = 61–66 | date = February 2007 | pmid = 16932856 | doi = 10.1007/s00787-006-0563-2 | type = Review | s2cid = 23831292 }}</ref> and is more common in females and individuals who also have a comorbid [[intellectual disability]].

===Fetal alcohol spectrum disorder===
[[Fetal alcohol spectrum disorder]]s (FASD) are a group of conditions that can occur in a person who is exposed to [[alcohol (drug)|alcohol]] during [[gestation]].<ref>{{cite web|date=April 16, 2015|title=Facts about FASDs|url=https://www.cdc.gov/ncbddd/fasd/facts.html|url-status=live|archive-url=https://web.archive.org/web/20150523194618/http://www.cdc.gov/ncbddd/fasd/facts.html|archive-date=23 May 2015|access-date=10 June 2015|df=dmy-all}}</ref> Behavioral traits of FASD can be similar to
those of ASD.<ref name="Overlapping Behavioral Characteristics of FASD's & Related Mental Health Diagnosis">{{cite web |title=Overlapping Behavioral Characteristics of FASD's & Related Mental Health Diagnosis |url=http://i1.wp.com/www.fasdfamilies.com/wp-content/uploads/2016/02/overlapping-characteristics-sources1.jpg?resize=791%2C1024 |website=www.fasdfamilies.com |publisher=Cathy Bruer-Thompson |access-date=28 July 2019}}</ref>  Evidence on the link between FASD and ASD is limited.<ref>{{cite web | title=Fetal Alcohol Spectrum Disorder vs. Autism Spectrum Disorder – Topical Reviews in Pediatrics | website=Topical Reviews in Pediatrics – Evidence-based information for professionals and families to achieve the best possible outcomes for the health, well-being, and success of children and adolescents. | date=2024-11-21 | url=https://trip.utah.edu/fetal-alcohol-spectrum-disorders-vs-autism-spectrum-disorder| access-date=2025-03-23}}</ref> Although results from studies are mixed, it is estimated that 2.6% of children with an FASD have an ASD as well, a rate almost two times higher than that reported in the general US population.<ref>{{cite journal |last1=Lange |first1=Shannon |last2=Rehm |first2=Jürgen |last3=Anagnostou |first3=Evdokia |last4=Popova |first4=Svetlana |title=Prevalence of externalizing disorders and Autism Spectrum Disorders among children with Fetal Alcohol Spectrum Disorder: systematic review and meta-analysis |journal=Biochemistry and Cell Biology |date=April 2018 |volume=96 |issue=2 |pages=241–251 |doi=10.1139/bcb-2017-0014 |pmid=35741677 |pmc=9221419 }}</ref> However, there is no information on the prevalence of FASD amongst those with ASD.

===Fragile X syndrome===
[[Fragile X syndrome]] is the most common inherited form of [[intellectual disability]]. It was so named because one part of the X chromosome has a defective piece that appears pinched and fragile when under a microscope. Fragile X syndrome represents an estimated 1% to 6% of all ASD cases.<ref>{{cite journal | last=Kaufmann | first=Walter E. | last2=Kidd | first2=Sharon A. | last3=Andrews | first3=Howard F. | last4=Budimirovic | first4=Dejan B. | last5=Esler | first5=Amy | last6=Haas-Givler | first6=Barbara | last7=Stackhouse | first7=Tracy | last8=Riley | first8=Catharine | last9=Peacock | first9=Georgina | last10=Sherman | first10=Stephanie L. | last11=Brown | first11=W. Ted | last12=Berry-Kravis | first12=Elizabeth | title=Autism Spectrum Disorder in Fragile X Syndrome: Cooccurring Conditions and Current Treatment | journal=Pediatrics | publisher=American Academy of Pediatrics (AAP) | volume=139 | issue=Supplement_3 |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC5619699/| date=2017-06-01 | issn=0031-4005 | doi=10.1542/peds.2016-1159f | doi-access=free | pages=S194–S206| pmc=5619699 }}</ref>

===Gender dysphoria===
{{main|Autism and LGBT identities#Autism and gender identity}}
[[Gender dysphoria]] is a diagnosis given to [[transgender]] people who experience discomfort related to their gender identity.<ref name="DSM-5 fact sheet">{{cite web|title=Gender Dysphoria|publisher=[[American Psychiatric Publishing]]|access-date=April 13, 2016|url=http://www.dsm5.org/documents/gender%20dysphoria%20fact%20sheet.pdf|archive-date=November 20, 2016|archive-url=https://web.archive.org/web/20161120125100/http://www.dsm5.org/documents/gender%20dysphoria%20fact%20sheet.pdf|url-status=live}}</ref> Autistic people are more likely to experience gender dysphoria.<ref>{{cite web| vauthors = Lauden K |title=Gender Identity Issues Linked to Autism, ADHD|publisher=MedScape|access-date=May 8, 2016|url=http://www.medscape.com/viewarticle/822077|archive-url=https://web.archive.org/web/20210118040828/https://www.medscape.com/viewarticle/822077|archive-date=January 18, 2021|url-status=live}}</ref><ref>{{cite journal | vauthors = Glidden D, Bouman WP, Jones BA, Arcelus J | title = Gender Dysphoria and Autism Spectrum Disorder: A Systematic Review of the Literature | journal = Sexual Medicine Reviews | volume = 4 | issue = 1 | pages = 3–14 | date = January 2016 | pmid = 27872002 | doi = 10.1016/j.sxmr.2015.10.003 | s2cid = 3454600 | url = https://figshare.com/articles/journal_contribution/9620366 | access-date = 2023-08-20 | archive-date = 2023-11-03 | archive-url = https://web.archive.org/web/20231103124238/https://figshare.com/articles/journal_contribution/Gender_dysphoria_and_autism_spectrum_disorder_a_systematic_review_of_the_literature/9620366 | url-status = live }}</ref><ref name="de VriesNoens2010">{{cite journal | vauthors = de Vries AL, Noens IL, Cohen-Kettenis PT, van Berckelaer-Onnes IA, Doreleijers TA | title = Autism spectrum disorders in gender dysphoric children and adolescents | journal = Journal of Autism and Developmental Disorders | volume = 40 | issue = 8 | pages = 930–936 | date = August 2010 | pmid = 20094764 | pmc = 2904453 | doi = 10.1007/s10803-010-0935-9 | doi-access = free }}</ref>  Around 20% of gender identity clinic-assessed individuals reported characteristics of ASD.<ref>{{cite journal | vauthors = Van Der Miesen AI, Hurley H, De Vries AL | title = Gender dysphoria and autism spectrum disorder: A narrative review | journal = International Review of Psychiatry | volume = 28 | issue = 1 | pages = 70–80 | date = 2016-01-02 | pmid = 26753812 | doi = 10.3109/09540261.2015.1111199 | s2cid = 20918937 | doi-access = free }}</ref>

===Hypermobility spectrum disorder and Ehlers–Danlos syndromes===
Studies have confirmed a link between hereditary connective tissue disorders such as [[Ehlers-Danlos syndromes]] (EDS) and [[hypermobility spectrum disorder]] (HSD) with autism, as a comorbidity and a co-occurrence within the same families.<ref>{{cite journal | vauthors = Casanova EL, Baeza-Velasco C, Buchanan CB, Casanova MF | title = The Relationship between Autism and Ehlers-Danlos Syndromes/Hypermobility Spectrum Disorders | journal = Journal of Personalized Medicine | volume = 10 | issue = 4 | pages = 260 | date = December 2020 | pmid = 33271870 | pmc = 7711487 | doi = 10.3390/jpm10040260 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Cederlöf M, Larsson H, Lichtenstein P, Almqvist C, Serlachius E, Ludvigsson JF | title = Nationwide population-based cohort study of psychiatric disorders in individuals with Ehlers-Danlos syndrome or hypermobility syndrome and their siblings | journal = BMC Psychiatry | volume = 16 | pages = 207 | date = July 2016 | pmid = 27377649 | pmc = 4932739 | doi = 10.1186/s12888-016-0922-6 | doi-access = free }}</ref>

===Intellectual disability===
The fraction of autistic individuals who also meet criteria for intellectual disability has been reported as anywhere from 25% to 70%. This wide variation illustrates the difficulty of assessing intelligence in autistic individuals.<ref>{{cite book |chapter=Learning in autism |vauthors=Dawson M, Mottron L, Gernsbacher MA |title=Learning and Memory: A Comprehensive Reference |volume=2 |pages=759–772 |editor=Byrne JH (-in-chief), Roediger HL III (vol.) |publisher=Academic Press |year=2008 |doi=10.1016/B978-012370509-9.00152-2 |isbn=978-0-12-370504-4 |chapter-url=http://gernsbacherlab.org/wp-content/uploads/papers/1/Dawson_AutisticLearning.pdf |access-date=2013-02-16 |archive-date=2018-04-13 |archive-url=https://web.archive.org/web/20180413012927/http://www.gernsbacherlab.org/wp-content/uploads/papers/1/Dawson_AutisticLearning.pdf |url-status=live }}</ref> For example, a 2001 British study of 26 autistic children found only about 30% with intelligence in the normal range ([[IQ]] above 70), 50% with a mild to moderate intellectual disability, and about 20% with a severe to profound intellectual disability (IQ below 35). For ASD other than autism the association is much weaker: the same study reported typical levels of intelligence in about 94% of 53 children with [[PDD-NOS]].<ref>{{cite journal | vauthors = Chakrabarti S, Fombonne E | title = Pervasive developmental disorders in preschool children | journal = JAMA | volume = 285 | issue = 24 | pages = 3093–3099 | date = June 2001 | pmid = 11427137 | doi = 10.1001/jama.285.24.3093 }}</ref> Estimates are that 40–69% of individuals with ASD have some degree of an intellectual disability,<ref name=MashBarkley2003>{{cite book|vauthors=Mash EJ, Barkley RA |title=Child Psychopathology|url=https://archive.org/details/childpsychopatho00mash_735 |url-access=limited |year=2003|publisher=The Guilford Press|location=New York|pages=[https://archive.org/details/childpsychopatho00mash_735/page/n421 409]–454|isbn=9781572306097}}</ref>  with females more likely to be in severe range of an intellectual disability. [[Learning disabilities]] are also highly comorbid in individuals with an ASD. Approximately 25–75% of individuals with an ASD also have some degree of learning disability,<ref name="Obrien & Pearson">{{cite journal | vauthors = O'Brien G, Pearson J | title = Autism and learning disability | journal = Autism | volume = 8 | issue = 2 | pages = 125–140 | date = June 2004 | pmid = 15165430 | doi = 10.1177/1362361304042718 | type = Review | s2cid = 17372893 }}</ref> although the types of learning disability vary depending on the specific strengths and weaknesses of the individual.

A 2006 review questioned the common assumption that most children with autism have an intellectual disability.<ref>{{cite journal |author=Edelson MG |year=2006 |title=Are the majority of children with autism mentally retarded? a systematic evaluation of the data |journal=Focus Autism Other Dev Disabl |volume=21 |issue=2 |pages=66–83 |url=http://www.willamette.edu/dept/comm/reprint/edelson/ |access-date=2007-04-15 |doi=10.1177/10883576060210020301 |s2cid=219975805 |archive-url=https://web.archive.org/web/20070704201502/http://www.willamette.edu/dept/comm/reprint/edelson/ |archive-date=2007-07-04 |url-status=dead |url-access=subscription }}</ref> It is possible that the association between an intellectual disability and autism is not because they usually have common causes, but because the presence of both makes it more likely that both will be diagnosed.<ref>{{cite journal | vauthors = Skuse DH | title = Rethinking the nature of genetic vulnerability to autistic spectrum disorders | journal = Trends in Genetics | volume = 23 | issue = 8 | pages = 387–395 | date = August 2007 | pmid = 17630015 | doi = 10.1016/j.tig.2007.06.003 }}</ref>

The CDC states that based on information from 11 reporting states 46% of people with autism have above 85 IQ.<ref>{{Cite web| url=https://www.cdc.gov/features/dsautismdata/| title=Diseases & Conditions &#124; Features &#124; CDC| date=2018-04-04| access-date=2017-09-09| archive-date=2017-11-19| archive-url=https://web.archive.org/web/20171119060937/https://www.cdc.gov/features/dsautismdata/| url-status=live}}</ref>

===Mitochondrial diseases===
The central player in [[bioenergetics]] is the [[mitochondrion]]. Mitochondria produce about 90% of cellular energy, regulate cellular redox status, produce [[Reactive oxygen species|ROS]], maintain {{Chem|Ca|2+}} [[homeostasis]], synthesize and degrade high-energy biochemical intermediates, and regulate [[cell death]] through activation of the [[mitochondrial permeability transition pore]] (mtPTP). When they fail, less and less energy is generated within the cell. Cell injury and even cell death follow. If this process is repeated throughout the body, whole organ systems begin to fail.

[[Mitochondrial disease]]s are a heterogeneous group of disorders that can affect multiple organs with varying severity. Symptoms may be acute or chronic with intermittent decompensation. Neurological manifestations include [[encephalopathy]], [[stroke]], cognitive regression, [[seizure]]s, [[cardiovascular disease|cardiopathies]]<ref>{{cite journal | vauthors = Siasos G, Tsigkou V, Kosmopoulos M, Theodosiadis D, Simantiris S, Tagkou NM, Tsimpiktsioglou A, Stampouloglou PK, Oikonomou E, Mourouzis K, Philippou A, Vavuranakis M, Stefanadis C, Tousoulis D, Papavassiliou AG | display-authors = 6 | title = Mitochondria and cardiovascular diseases-from pathophysiology to treatment | journal = Annals of Translational Medicine | volume = 6 | issue = 12 | pages = 256 | date = June 2018 | pmid = 30069458 | pmc = 6046286 | doi = 10.21037/atm.2018.06.21 | doi-access = free }}</ref> (cardiac conduction defects, [[hypertensive heart disease]], [[cardiomyopathy]],<ref>{{cite journal | vauthors = El-Hattab AW, Scaglia F | title = Mitochondrial Cardiomyopathies | journal = Frontiers in Cardiovascular Medicine | volume = 3 | pages = 25 | year = 2016 | pmid = 27504452 | pmc = 4958622 | doi = 10.3389/fcvm.2016.00025 | doi-access = free }}</ref> etc...), [[Diabetes mellitus|diabetes]], [[Visual impairment|visual]] and [[hearing loss]], [[organ failure]], [[neuropathic pain]] and [[peripheral neuropathy]].

Mitochondrial disease is estimated to affect less than 0.1% of the general population.<ref name=pmid25019065>{{cite journal | vauthors = Frye RE, Rossignol DA | title = Treatments for biomedical abnormalities associated with autism spectrum disorder | journal = Frontiers in Pediatrics | volume = 2 | pages = 66 | year = 2014 | pmid = 25019065 | pmc = 4073259 | doi = 10.3389/fped.2014.00066 | doi-access = free }}</ref> Approximately 5% of autistic children meet the criteria for classical mitochondrial dysfunction.<ref name="Rossignol">{{cite journal | vauthors = Rossignol DA, Frye RE | title = Mitochondrial dysfunction in autism spectrum disorders: a systematic review and meta-analysis | journal = Molecular Psychiatry | volume = 17 | issue = 3 | pages = 290–314 | date = March 2012 | pmid = 21263444 | pmc = 3285768 | doi = 10.1038/mp.2010.136 }}</ref> It is unclear why this mitochondrial disease occurs, considering that only 23% of children with both ASD and mitochondrial disease present with [[mitochondrial DNA]] abnormalities.<ref name="Rossignol" />

=== Neurofibromatosis type I ===
ASD is also associated with [[neurofibromatosis type I]] (NF-1).<ref>{{Cite web|date=2018-06-08|title=Neurofibromatosis type 1 - Symptoms|url=https://www.nhs.uk/conditions/neurofibromatosis-type-1/symptoms/|access-date=2020-09-21|website=nhs.uk|language=en|archive-date=2015-09-25|archive-url=https://web.archive.org/web/20150925015544/http://www.nhs.uk/Conditions/Neurofibromatosis/Pages/Symptoms.aspx|url-status=live}}</ref> NF-1 is a complex multi-system human disorder caused by the mutation of a gene on [[chromosome 17]] that is responsible for production of a protein, called [[neurofibromin 1]], which is needed for normal function in many human cell types. NF-1 causes tumors along the nervous system which can grow anywhere on the body. NF-1 is one of the most common genetic disorders and is not limited to any person's race or sex. NF-1 is an [[autosomal dominant]] disorder, which means that mutation or deletion of one copy (or allele) of the NF-1 gene is sufficient for the development of NF-1, although presentation varies widely and is often different even between relatives affected by NF-1.

===Neuroinflammation and immune disorders===
The role of the [[immune system]] and neuroinflammation in the development of autism is controversial. Until recently, there was scant evidence supporting immune hypotheses, but research into the role of immune response and neuroinflammation may have important clinical and therapeutic implications. The exact role of heightened immune response in the [[central nervous system]] (CNS) of patients with autism is uncertain, but may be a primary factor in triggering and sustaining many of the comorbid conditions associated with autism. Recent studies indicate the presence of heightened neuroimmune activity in both the brain tissue and the [[cerebrospinal fluid]] of patients with autism, supporting the view that heightened immune response may be an essential factor in the onset of autistic symptoms.<ref name="pmid16401547">{{cite journal | vauthors = Pardo CA, Vargas DL, Zimmerman AW | title = Immunity, neuroglia and neuroinflammation in autism | journal = International Review of Psychiatry | volume = 17 | issue = 6 | pages = 485–495 | date = December 2005 | pmid = 16401547 | doi = 10.1080/02646830500381930 | s2cid = 849995 | citeseerx = 10.1.1.504.8397 }}</ref> A 2013 review also found evidence of [[microglia]]l activation and increased [[cytokine]] production in [[Postmortem studies|postmortem brain samples]] from people with autism.<ref>{{cite journal | vauthors = Gesundheit B, Rosenzweig JP, Naor D, Lerer B, Zachor DA, Procházka V, Melamed M, Kristt DA, Steinberg A, Shulman C, Hwang P, Koren G, Walfisch A, Passweg JR, Snowden JA, Tamouza R, Leboyer M, Farge-Bancel D, Ashwood P | display-authors = 6 | title = Immunological and autoimmune considerations of Autism Spectrum Disorders | journal = Journal of Autoimmunity | volume = 44 | pages = 1–7 | date = August 2013 | pmid = 23867105 | doi = 10.1016/j.jaut.2013.05.005 }}</ref>

===Neuropathies===
The prevalence of [[peripheral neuropathies]] would be significantly increased in ASD.<ref>{{cite journal | vauthors = Frye RE, Rossignol DA | title = Mitochondrial dysfunction can connect the diverse medical symptoms associated with autism spectrum disorders | journal = Pediatric Research | volume = 69 | issue = 5 Pt 2 | pages = 41R–47R | date = May 2011 | pmid = 21289536 | pmc = 3179978 | doi = 10.1203/PDR.0b013e318212f16b }}</ref> Peripheral neuropathies may be asymptomatic. Peripheral neuropathy is a common manifestation of mitochondrial diseases<ref>{{cite journal | vauthors = Luigetti M, Sauchelli D, Primiano G, Cuccagna C, Bernardo D, Lo Monaco M, Servidei S | title = Peripheral neuropathy is a common manifestation of mitochondrial diseases: a single-centre experience | journal = European Journal of Neurology | volume = 23 | issue = 6 | pages = 1020–1027 | date = June 2016 | pmid = 26822221 | doi = 10.1111/ene.12954 | s2cid = 3914392 }}</ref> and [[polyneuropathies]] would be relatively common.<ref>{{cite journal | vauthors = Luigetti M, Primiano G, Cuccagna C, Bernardo D, Sauchelli D, Vollono C, Servidei S | title = Small fibre neuropathy in mitochondrial diseases explored with sudoscan | journal = Clinical Neurophysiology | volume = 129 | issue = 8 | pages = 1618–1623 | date = August 2018 | pmid = 29890373 | doi = 10.1016/j.clinph.2018.04.755 | s2cid = 48364519 }}</ref> [[Neuropathies]] could also be caused by other features of ASD.

=== Obsessive–compulsive disorder ===
[[Obsessive–compulsive disorder]] is characterized by recurrent obsessive thoughts or compulsive acts. About 30% of individuals with autism spectrum disorders also have OCD.<ref>{{cite journal | vauthors = Russell AJ, Jassi A, Fullana MA, Mack H, Johnston K, Heyman I, Murphy DG, Mataix-Cols D | display-authors = 6 | title = Cognitive behavior therapy for comorbid obsessive-compulsive disorder in high-functioning autism spectrum disorders: a randomized controlled trial | journal = Depression and Anxiety | volume = 30 | issue = 8 | pages = 697–708 | date = August 2013 | pmid = 23389964 | doi = 10.1002/da.22053 | s2cid = 13587266 | url = https://purehost.bath.ac.uk/ws/files/84038359/Accepted_version.pdf | access-date = 2023-08-20 | archive-date = 2023-09-08 | archive-url = https://web.archive.org/web/20230908095154/https://purehost.bath.ac.uk/ws/files/84038359/Accepted_version.pdf | url-status = live }}</ref>

=== Obsessive–compulsive personality disorder ===
[[Obsessive–compulsive personality disorder]] (OCPD) is a [[Cluster C|cluster C personality disorder]] characterized by a general pattern of excessive concern with orderliness, [[Perfectionism (psychology)|perfectionism]], attention to details, mental and interpersonal [[Control (psychology)|control]] and a need for control over one's environment which interferes with personal [[Flexibility (personality)|flexibility]], [[openness to experience]] and [[efficiency]] as well as interfering with relationships.

There are considerable similarities and overlap between autism and OCPD,<ref name="Gillberg&Billstedt2000">{{cite journal | vauthors = Gillberg C, Billstedt E | title = Autism and Asperger syndrome: coexistence with other clinical disorders | journal = Acta Psychiatrica Scandinavica | volume = 102 | issue = 5 | pages = 321–330 | date = November 2000 | pmid = 11098802 | doi = 10.1034/j.1600-0447.2000.102005321.x | s2cid = 40070782 }}</ref> such as list-making, inflexible adherence to rules and obsessive aspects of routines, though the latter may be distinguished from OCPD especially regarding [[Affect (psychology)|affective]] behaviors, bad social skills, difficulties with [[Theory of mind#Autism|theory of mind]] and intense intellectual interests e.g. an ability to recall every aspect of a hobby.<ref name="Fitzgerald2001a">{{Cite journal| vauthors = Fitzgerald M, Corvin A |date=2001-07-01|title=Diagnosis and differential diagnosis of Asperger syndrome|journal=Advances in Psychiatric Treatment|volume=7|issue=4|pages=310–318|doi=10.1192/apt.7.4.310|issn=1355-5146|doi-access=free}}</ref>

=== Psychosis and schizophrenia ===
{{See also|Social construction of schizophrenia#Science of schizophrenia and comorbid conditions|l1=Schizophrenia and comorbid conditions}}
[[Childhood schizophrenia|Childhood-onset schizophrenia]] is preceded by childhood autistic spectrum disorders in almost half of cases, and an increasing number of similarities are being discovered between the two disorders.<ref>{{cite journal | vauthors = Rapoport J, Chavez A, Greenstein D, Addington A, Gogtay N | title = Autism spectrum disorders and childhood-onset schizophrenia: clinical and biological contributions to a relation revisited | journal = Journal of the American Academy of Child and Adolescent Psychiatry | volume = 48 | issue = 1 | pages = 10–18 | date = January 2009 | pmid = 19218893 | pmc = 2664646 | doi = 10.1097/CHI.0b013e31818b1c63 }}</ref>

Studies have also found that the presence of [[psychosis]] in adulthood is significantly higher in those with autism spectrum disorders, especially those with [[Pervasive developmental disorder not otherwise specified|PDD-NOS]], than in the general population.<ref>{{cite journal | vauthors = Mouridsen SE, Rich B, Isager T | title = Psychiatric disorders in adults diagnosed as children with atypical autism. A case control study | journal = Journal of Neural Transmission | volume = 115 | issue = 1 | pages = 135–138 | date = 2008 | pmid = 17768593 | doi = 10.1007/s00702-007-0798-1 | s2cid = 34532555 }}</ref> This psychosis generally occurs in an unusual way, with most individuals with ASD experiencing a highly atypical collection of symptoms. Recent studies have also found that the core ASD symptoms also generally present in a slightly different way during the childhood of the individuals that will later become psychotic, long before the actual psychosis develops.<ref>{{cite journal | vauthors = Larson FV, Wagner AP, Jones PB, Tantam D, Lai MC, Baron-Cohen S, Holland AJ | title = Psychosis in autism: comparison of the features of both conditions in a dually affected cohort | journal = The British Journal of Psychiatry | volume = 210 | issue = 4 | pages = 269–275 | date = April 2017 | pmid = 27979819 | pmc = 5376719 | doi = 10.1192/bjp.bp.116.187682 }}</ref>

=== Schizoid personality disorder ===
[[Schizoid personality disorder]] (SPD) is a [[personality disorder]] characterized by a [[Asociality|lack of interest in social relationships]], a tendency towards a solitary or sheltered lifestyle, secretiveness, emotional coldness, detachment and [[apathy]]. Other associated features include [[stilted speech]], a [[Anhedonia|lack of deriving enjoyment]] from most, if not all, activities, feeling as though one is an "observer" rather than a participant in life, an inability to tolerate emotional expectations of others, apparent indifference when praised or criticised, a degree of [[asexuality]] and idiosyncratic moral or political beliefs.<ref name="Akhtar">{{cite journal | vauthors = Akhtar S | title = Schizoid personality disorder: a synthesis of developmental, dynamic, and descriptive features | journal = American Journal of Psychotherapy | volume = 41 | issue = 4 | pages = 499–518 | date = October 1987 | pmid = 3324773 | doi = 10.1176/appi.psychotherapy.1987.41.4.499 | url = https://books.google.com/books?id=bU0eAAAAQBAJ&pg=PA121 | access-date = 2017-02-10 | url-status = live | isbn = 9781461627685 | archive-url = https://web.archive.org/web/20170731160223/https://books.google.de/books?id=bU0eAAAAQBAJ&pg=PA121 | archive-date = 2017-07-31 | url-access = subscription }}</ref> Symptoms typically start in late childhood or adolescence.<ref name="Medline">{{cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/000920.htm|title=Schizoid Personality Disorder|work=[[MedlinePlus]]|date=2014|publisher=National Library of Medicine|access-date=2019-08-21|archive-date=2016-07-05|archive-url=https://web.archive.org/web/20160705124629/https://www.nlm.nih.gov/medlineplus/ency/article/000920.htm|url-status=live}}</ref>

Several studies have reported an overlap, confusion or comorbidity with [[Asperger syndrome]] (which has been combined with autism spectrum disorder and no longer appears as a diagnostic label in the DSM-5).<ref name="Tantam_1988">{{cite journal | vauthors = Tantam D | title = Lifelong eccentricity and social isolation. II: Asperger's syndrome or schizoid personality disorder? | journal = The British Journal of Psychiatry | volume = 153 | pages = 783–791 | date = December 1988 | pmid = 3256377 | doi = 10.1192/bjp.153.6.783 | s2cid = 39433805 }}</ref><ref>{{Cite book|title=Integrated Treatment for Co-Occurring Disorders: Personality Disorders and Addiction| vauthors = Ekleberry SC |publisher=Routledge|year=2008|isbn=978-0789036933|pages=31–32|chapter=Cluster A - Schizoid Personality Disorder and Substance Use Disorders|chapter-url=https://books.google.com/books?id=O5HY1xcfjEcC&pg=PA31}}</ref><ref name="Lugnegård_2012">{{cite journal | vauthors = Lugnegård T, Hallerbäck MU, Gillberg C | title = Personality disorders and autism spectrum disorders: what are the connections? | journal = Comprehensive Psychiatry | volume = 53 | issue = 4 | pages = 333–340 | date = May 2012 | pmid = 21821235 | doi = 10.1016/j.comppsych.2011.05.014 }}</ref> Asperger syndrome was at one time called "[[schizoid disorder of childhood]]". [[Eugen Bleuler]] coined the term "autism" to describe withdrawal to an internal fantasy, against which any influence from outside becomes an intolerable disturbance.<ref>{{cite journal | vauthors = Kuhn R | title = Eugen Bleuler's concepts of psychopathology | journal = History of Psychiatry | volume = 15 | issue = 59 Pt 3 | pages = 361–366 | date = September 2004 | pmid = 15386868 | doi = 10.1177/0957154X04044603 | s2cid = 5317716 }} The quote is a translation of Bleuler's 1910 original.</ref>

In a 2012 study of a sample of 54 young adults with Asperger syndrome, it was found that 26% of them also met criteria for SPD, the highest comorbidity out of any personality disorder in the sample (the other comorbidities were 19% for obsessive–compulsive personality disorder, 13% for [[avoidant personality disorder]] and one female with [[schizotypal personality disorder]]). Additionally, twice as many men with Asperger syndrome met criteria for SPD than women. While 41% of the whole sample were unemployed with no occupation, this rose to 62% for the Asperger's and SPD comorbid group.<ref name="Lugnegård_2012" />{{Non-primary source needed|date=March 2025}}

Although the cause for this comorbidity is not yet certain, genetic evidence for a spectrum between [[cluster A personality disorders]]/[[schizophrenia]] and autism spectrum disorders has been found.<ref>{{cite journal | vauthors = Crespi B, Badcock C | title = Psychosis and autism as diametrical disorders of the social brain | journal = The Behavioral and Brain Sciences | volume = 31 | issue = 3 | pages = 241–261 | date = June 2008 | pmid = 18578904 | doi = 10.1017/S0140525X08004214 | url = http://eprints.lse.ac.uk/21571/1/Psychosis%20and%20autism%20as%20diametrical%20disorders%20of%20the%20social%20brain%20%28LSERO%29.pdf | access-date = 2019-11-29 | archive-date = 2020-04-12 | archive-url = https://web.archive.org/web/20200412200311/http://eprints.lse.ac.uk/21571/1/Psychosis%20and%20autism%20as%20diametrical%20disorders%20of%20the%20social%20brain%20%28LSERO%29.pdf | url-status = live }}</ref><ref>{{cite journal | vauthors = Crespi B, Stead P, Elliot M | title = Evolution in health and medicine Sackler colloquium: Comparative genomics of autism and schizophrenia | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 107 | issue = Suppl 1 | pages = 1736–1741 | date = January 2010 | pmid = 19955444 | pmc = 2868282 | doi = 10.1073/pnas.0906080106 | doi-access = free | bibcode = 2010PNAS..107.1736C }}</ref><ref>{{cite journal | vauthors = Ciaramidaro A, Bölte S, Schlitt S, Hainz D, Poustka F, Weber B, Bara BG, Freitag C, Walter H | display-authors = 6 | title = Schizophrenia and autism as contrasting minds: neural evidence for the hypo-hyper-intentionality hypothesis | journal = Schizophrenia Bulletin | volume = 41 | issue = 1 | pages = 171–179 | date = January 2015 | pmid = 25210055 | pmc = 4266299 | doi = 10.1093/schbul/sbu124 }}</ref><ref name=":0" group="note">See [[Imprinted brain hypothesis]], [[Causes of schizophrenia#Genetic candidates|Causes of schizophrenia]], [[DUF1220]]</ref> [[Digby Tantam|Tantam]] suggested that Asperger syndrome may confer an increased risk of developing SPD.<ref name="Tantam_1988" />

In the same 2012 study, it was noted that the [[Diagnostic and Statistical Manual of Mental Disorders|DSM]] may complicate diagnosis of SPD by requiring the exclusion of a [[pervasive developmental disorder]] (PDD) before establishing a diagnosis of SPD. The study found that social interaction, stereotyped behaviours and specific interests were more severe in the individuals with Asperger syndrome also fulfilling SPD criteria, against the notion that social interaction skills are unimpaired in SPD. The authors believe that a substantial subgroup of people with autism spectrum disorder or PDD have clear "schizoid traits" and correspond largely to the "loners" in [[Lorna Wing]]'s classification ''The autism spectrum'' (''[[The Lancet|Lancet]]'' 1997), described by [[Sula Wolff]].<ref name="Lugnegård_2012" />{{Non-primary source needed|date=March 2025}}

=== Self-injury and suicide ===
[[Self-harm|Self-injurious behaviors]] are relatively common in autistic people, and can include head-banging, self-cutting, self-biting, and hair-pulling.<ref name="Mins2014">{{cite journal |vauthors=Minshawi NF, Hurwitz S, Fodstad JC, Biebl S, Morriss DH, McDougle CJ |title=The association between self-injurious behaviors and autism spectrum disorders |journal=[[Psychology Research and Behavior Management]] |volume=7 |pages=125–36 |date=April 2014 |pmid=24748827 |pmc=3990505 |doi=10.2147/PRBM.S44635 |doi-access=free}}</ref> Some of these can result in serious injury or death.<ref name="Mins2014" />  Autistic people are about three times as likely as non-autistic people to engage in self-injury.<ref name=":2">{{Cite journal |last1=Blanchard |first1=Ashley |last2=Chihuri |first2=Stanford |last3=DiGuiseppi |first3=Carolyn G. |last4=Li |first4=Guohua |date=2021-10-01 |title=Risk of Self-harm in Children and Adults With Autism Spectrum Disorder: A Systematic Review and Meta-analysis |journal=JAMA Network Open |volume=4 |issue=10 |pages=e2130272 |doi=10.1001/jamanetworkopen.2021.30272 |issn=2574-3805 |pmc=8527356 |pmid=34665237}}</ref>

Theories about the cause of self-injurious behavior in children with developmental delay, including autistic children, include:<ref name="Oliver2015">{{cite journal |vauthors=Oliver C, Richards C |title=Practitioner Review: Self-injurious behaviour in children with developmental delay |journal=[[Journal of Child Psychology and Psychiatry]] |volume=56 |issue=10 |pages=1042–54 |date=October 2015 |pmid=25916173 |doi=10.1111/jcpp.12425 |s2cid=206034400 |url=http://pure-oai.bham.ac.uk/ws/files/26880648/Oliver_Richards_2015_Self_injurious_behaviour_children_dev._delay_JCPP.pdf |type=Review |access-date=25 August 2020 |archive-date=12 August 2023 |archive-url=https://web.archive.org/web/20230812175509/http://pure-oai.bham.ac.uk/ws/files/26880648/Oliver_Richards_2015_Self_injurious_behaviour_children_dev._delay_JCPP.pdf |url-status=live}}</ref>
* Frequency or continuation of self-injurious behavior can be influenced by environmental factors (e.g., reward in return for halting self-injurious behavior). This theory does not apply to younger children with autism. There is some evidence that frequency of self-injurious behavior can be reduced by removing or modifying environmental factors that reinforce the behavior.<ref name="Oliver2015" />{{rp|10–12|}}
* Higher rates of self-injury are noted in socially isolated autistic people. Studies have shown that a lack of socialization skills are related factors to self-injurious behavior for autistic people.<ref>{{cite journal |vauthors=Flowers J, Lantz J, Hamlin T, Simeonsson RJ |title=Associated Factors of Self-injury Among Adolescents with Autism Spectrum Disorder in a Community and Residential Treatment Setting |journal=[[Journal of Autism and Developmental Disorders]] |volume=50 |issue=8 |pages=2987–3004 |date=August 2020 |pmid=32056114 |doi=10.1007/s10803-020-04389-4 |s2cid=211111895}}</ref>
* Self-injury could be a response to modulate [[Nociception|pain perception]] when chronic pain or other health problems that cause pain are present.<ref name="Oliver2015" />{{rp|12-13|q=In the last decade a number of studies has emerged which indicate that pain might directly cause self-injury ... Self-injury could moderate the perception of pain caused by ongoing health problem}}
* Abnormal [[basal ganglia]] connectivity may predispose to self-injurious behavior.<ref name="Oliver2015" />{{rp|13|q=In a recent review, Muehlmann and Lewis (2012) concluded that alterations in cortical basal ganglia circuitry underlie both self-injurious and stereotypic/compulsive behaviours.}}

Risk factors for self-harm and [[suicidality]] include circumstances that could affect anyone, such as [[mental health problems]] (e.g., [[anxiety disorder]]) and social problems (e.g., [[unemployment]] and [[social isolation]]), plus factors that affect only autistic people, such as actively trying to behave like a neurotypical person, which is called [[Autistic masking|''masking'']].<ref name=":3">{{Cite journal |last1=Newell |first1=Victoria |last2=Phillips |first2=Lucy |last3=Jones |first3=Chris |last4=Townsend |first4=Ellen |last5=Richards |first5=Caroline |last6=Cassidy |first6=Sarah |date=2023-03-15 |title=A systematic review and meta-analysis of suicidality in autistic and possibly autistic people without co-occurring intellectual disability |journal=Molecular Autism |volume=14 |issue=1 |pages=12 |doi=10.1186/s13229-023-00544-7 |doi-access=free |issn=2040-2392 |pmid=36922899|pmc=10018918 }}</ref> Approximately 8 in 10 people with autism suffer from a mental health problem in their lifetime, in comparison to 1 in 4 of the general population that suffers from a mental health problem in their lifetimes.<ref name="Autistica, 1">{{cite web |title= Depression and autism |url= https://www.autistica.org.uk/what-is-autism/depression-and-autism |website= Autistica |date= 14 March 2024 |access-date= 23 January 2025}}</ref><ref name="Autistica, 2">{{cite web |title=Suicide and autism  |url= https://www.autistica.org.uk/what-is-autism/suicide-and-autism |website= Autistica |date= 7 March 2024 |access-date= 23 January 2025}}</ref><ref name="JADD">{{cite journal |first1= Anne |last1= Lever |first2= Geurts |last2= Hilde |date= 2016 |title= Psychiatric Co-occurring Symptoms and Disorders in Young, Middle-Aged, and Older Adults with Autism Spectrum Disorder |journal= Journal of Autism and Developmental Disorders |volume= 46 |issue= 6 |pages= 1916–1930 |doi= 10.1007/s10803-016-2722-8  |pmid= 26861713 |pmc= 4860203 }}</ref>

Rates of suicidality vary significantly depending upon what is being measured.<ref name=":3" />  This is partly because questionnaires developed for neurotypical subjects are not always valid for autistic people.<ref name=":3" />  As of 2023, the Suicidal Behaviours Questionnaire–Autism Spectrum Conditions (SBQ-ASC) is the only test [[Test validity|validated]] for autistic people.<ref name=":3" /> According to some estimates, about a quarter of autistic youth<ref name=":4">{{Cite journal |last1=O'Halloran |first1=L. |last2=Coey |first2=P. |last3=Wilson |first3=C. |date=April 2022 |title=Suicidality in autistic youth: A systematic review and meta-analysis |journal=Clinical Psychology Review |volume=93 |pages=102144 |doi=10.1016/j.cpr.2022.102144 |issn=1873-7811 |pmid=35290800|doi-access=free }}</ref> and a third of all autistic people<ref name=":3" /><ref name=":5">{{Cite journal |last1=Huntjens |first1=Anne |last2=Landlust |first2=Annemiek |last3=Wissenburg |first3=Sophie |last4=van der Gaag |first4=Mark |date=March 2024 |title=The Prevalence of Suicidal Behavior in Autism Spectrum Disorder |url=https://pubmed.ncbi.nlm.nih.gov/37668055/ |journal=Crisis |volume=45 |issue=2 |pages=144–153 |doi=10.1027/0227-5910/a000922 |issn=2151-2396 |pmid=37668055|hdl=1871.1/2e96e0d9-7230-421a-bb77-834a9c4ae2bb |hdl-access=free }}</ref> have experienced [[suicidal ideation]] at some point. Rates of suicidal ideation are the same for people formally diagnosed with autism and people who have typical intelligence and are believed to have autism but have not been diagnosed.<ref name=":3" /> The suicide rate for verbal autistics is nine times that of the general population.<ref name="The Guardian">{{cite news |url=https://www.theguardian.com/society/2023/jul/31/autism-could-be-seen-as-part-of-personality-for-some-diagnosed-experts-say |title=Autism could be seen as part of personality for some diagnosed, experts say |first=Amelia |last=Hill |date=31 July 2023 |newspaper=[[The Guardian]] |access-date=1 August 2023 |archive-date=1 August 2023 |archive-url=https://web.archive.org/web/20230801022836/https://www.theguardian.com/society/2023/jul/31/autism-could-be-seen-as-part-of-personality-for-some-diagnosed-experts-say |url-status=live}}</ref> In a 2014 study of late diagnosed autistic adults, 66% had experienced suicidal ideation (nine times higher than the general population) and 35% had a suicide plan or had made a [[suicide attempt]].<ref>Cassidy S, Bradley P, Robinson J, Allison C, McHugh M, Baron-Cohen S. Suicidal ideation and suicide plans or attempts in adults with Asperger’s syndrome attending a specialist diagnostic clinic: a clinical cohort study. The Lancet Psychiatry. 2014;1(2):142–7</ref>

Although most people who attempt suicide are not autistic,<ref name=":3" /> autistic people are about three times as likely as non-autistic people to make a [[suicide attempt]].<ref name=":2" /><ref name=":6">{{Cite journal |last1=Santomauro |first1=Damian F. |last2=Hedley |first2=Darren |last3=Sahin |first3=Ensu |last4=Brugha |first4=Traolach S. |last5=Naghavi |first5=Mohsen |last6=Vos |first6=Theo |last7=Whiteford |first7=Harvey A. |last8=Ferrari |first8=Alize J. |last9=Stokes |first9=Mark A. |date=November 2024 |title=The global burden of suicide mortality among people on the autism spectrum: A systematic review, meta-analysis, and extension of estimates from the Global Burden of Disease Study 2021 |url=https://pubmed.ncbi.nlm.nih.gov/39197224/ |journal=Psychiatry Research |volume=341 |pages=116150 |doi=10.1016/j.psychres.2024.116150 |issn=1872-7123 |pmid=39197224}}</ref> Less than 10% of autistic youth have attempted suicide,<ref name=":4" /> but 15% to 25% autistic adults have.<ref name=":3" /><ref name=":5" /> The rates of suicide attempts are the same among people formally diagnosed with autism and those who have typical intelligence and are believed to have autism but have not been diagnosed.<ref name=":3" /> The suicide risk is lower among [[cisgender]] autistic males and autistic people with [[intellectual disabilities]].<ref name=":3" /><ref name=":6" /> The rate of suicide results in a global [[excess mortality]] among autistic people equal to approximately 2% of all suicide deaths each year.<ref name=":6" />

===Sensory problems===
{{further|Sensory processing disorder}}
Unusual responses to [[Stimulus (physiology)|sensory stimuli]] are more common and prominent in individuals with autism, and sensory abnormalities are commonly recognized as diagnostic criteria in autism spectrum disorder (ASD), as reported in the DSM-5; although there is no good evidence that sensory symptoms differentiate autism from other developmental disorders.<ref>{{cite journal | vauthors = Rogers SJ, Ozonoff S | title = Annotation: what do we know about sensory dysfunction in autism? A critical review of the empirical evidence | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 46 | issue = 12 | pages = 1255–1268 | date = December 2005 | pmid = 16313426 | doi = 10.1111/j.1469-7610.2005.01431.x }}</ref> [[Sensory processing disorder]] is comorbid with ASD, with comorbidity rates of 42–88%.<ref name=Baranek2002>{{cite journal | vauthors = Baranek GT | title = Efficacy of sensory and motor interventions for children with autism | journal = Journal of Autism and Developmental Disorders | volume = 32 | issue = 5 | pages = 397–422 | date = October 2002 | pmid = 12463517 | doi = 10.1023/A:1020541906063 | type = Review | s2cid = 16449130 }}</ref> With or without meeting the standards of SPD, about 90% of ASD individuals have some type of atypical sensory experiences, described as both hyper- and hypo-reactivity.<ref>{{cite journal | vauthors = Balasco L, Provenzano G, Bozzi Y | title = Sensory Abnormalities in Autism Spectrum Disorders: A Focus on the Tactile Domain, From Genetic Mouse Models to the Clinic | journal = Frontiers in Psychiatry | volume = 10 | pages = 1016 | date = 28 January 2020 | pmid = 32047448 | pmc = 6997554 | doi = 10.3389/fpsyt.2019.01016 | doi-access = free }}</ref> The prevalence of reported "unusual sensory ''behaviors''" that affect functioning in everyday life is also higher, ranging from 45 to 95% depending on factors such as age, IQ and the control group used.<ref>{{cite journal | vauthors = Kojovic N, Ben Hadid L, Franchini M, Schaer M | title = Sensory Processing Issues and Their Association with Social Difficulties in Children with Autism Spectrum Disorders | journal = Journal of Clinical Medicine | volume = 8 | issue = 10 | page = 1508 | date = September 2019 | pmid = 31547076 | pmc = 6833094 | doi = 10.3390/jcm8101508 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Perez Repetto L, Jasmin E, Fombonne E, Gisel E, Couture M | title = Longitudinal Study of Sensory Features in Children with Autism Spectrum Disorder | journal = Autism Research and Treatment | volume = 2017 | pages = 1934701 | date = 27 August 2017 | pmid = 28932599 | pmc = 5592014 | doi = 10.1155/2017/1934701 | doi-access = free }}</ref>

Several studies have reported associated motor problems that include [[poor muscle tone]], [[Developmental coordination disorder|poor motor planning]], and [[toe walking]]; ASD is not associated with severe motor disturbances.<ref>{{cite journal | vauthors = Ming X, Brimacombe M, Wagner GC | title = Prevalence of motor impairment in autism spectrum disorders | journal = Brain & Development | volume = 29 | issue = 9 | pages = 565–570 | date = October 2007 | pmid = 17467940 | doi = 10.1016/j.braindev.2007.03.002 | s2cid = 9648682 }}</ref>

Many with ASD often find it uncomfortable to sit or stand in a way which neurotypical people will find ordinary, and may stand in an awkward position, such as with both feet together, supinating, sitting cross-legged or with one foot on top of the other or simply having an awkward gait. However, despite evidently occurring more often in people with ASD, all evidence is anecdotal and unresearched at this point. It has been observed by some psychologists that there is commonality to the way in which these 'awkward' positions may manifest.<ref>{{citation |author=Carry Terra |title=Adults on the Spectrum: These are your Feet on Asperger's}} http://www.aspiestrategy.com/2013/02/adults-on-spectrum-these-are-your-feet.html?m=1 {{Webarchive|url=https://web.archive.org/web/20160923123840/http://www.aspiestrategy.com/2013/02/adults-on-spectrum-these-are-your-feet.html?m=1 |date=2016-09-23 }}</ref>

===Sleep disorders===
Sleep disorders are commonly reported by parents of individuals with ASDs, including late sleep onset, early morning awakening, and poor sleep maintenance;<ref name=Canitano />  sleep disturbances are present in 53–78% of individuals with ASD.<ref name=Malow2012>{{cite journal | vauthors = Malow BA, Byars K, Johnson K, Weiss S, Bernal P, Goldman SE, Panzer R, Coury DL, Glaze DG | display-authors = 6 | title = A practice pathway for the identification, evaluation, and management of insomnia in children and adolescents with autism spectrum disorders | journal = Pediatrics | volume = 130 | issue = Suppl 2 | pages = S106–S124 | date = November 2012 | pmid = 23118242 | pmc = 9923883 | doi = 10.1542/peds.2012-0900I | s2cid = 15066964 }}</ref>  Unlike general pediatric [[insomnia]], which has its roots in behavior, sleep disorders in individuals with ASD are comorbid with other neurobiological, medical, and psychiatric issues.<ref name="Malow2012"/>

If not addressed, severe sleep disorders can exacerbate ASD behaviors such as [[self-injury]];<ref>{{cite web|title=Poor sleep in children with autism associated with problematic behavior during the day|url=http://www.truthlyapp.com/truths/495-poor-sleep-in-children-with-autism-associated-with-problematic-behavior-during-the-day|website=Truthly|access-date=5 February 2015|archive-url=https://web.archive.org/web/20150205231729/http://www.truthlyapp.com/truths/495-poor-sleep-in-children-with-autism-associated-with-problematic-behavior-during-the-day|archive-date=5 February 2015|url-status=usurped}}</ref> however, there are no [[Food and Drug Administration]]-approved pharmacological treatments for pediatric insomnia at this time.<ref name=Johnson2008>{{cite journal | vauthors = Johnson KP, Malow BA | title = Assessment and pharmacologic treatment of sleep disturbance in autism | journal = Child and Adolescent Psychiatric Clinics of North America | volume = 17 | issue = 4 | pages = 773–85, viii | date = October 2008 | pmid = 18775369 | doi = 10.1016/j.chc.2008.06.006 }}</ref>

Studies have found abnormalities in the physiology of melatonin and circadian rhythm in people with autism spectrum disorders (ASD).<ref>{{Cite journal |last=Wu |first=Zhou-yue |date=October 2020 |title=Autism spectrum disorder (ASD): Disturbance of the melatonin system and its implications |journal=Biomedicine & Pharmacotherapy |volume=130|doi=10.1016/j.biopha.2020.110496 |pmid=32682113 |doi-access=free }}</ref> Some evidence suggests that [[melatonin]] supplements improve sleep patterns in children with autism but robust, high-quality studies are overall lacking.<ref>{{cite web|title=Melatonin supplementation associated with improved sleep and behavior in children with autism|url=http://www.truthlyapp.com/truths/496-melatonin-supplementation-associated-with-improved-sleep-and-behavior-in-children-with-autism|website=Truthly|access-date=5 February 2015|archive-url=https://web.archive.org/web/20150205230007/http://www.truthlyapp.com/truths/496-melatonin-supplementation-associated-with-improved-sleep-and-behavior-in-children-with-autism|archive-date=5 February 2015|url-status=usurped}}</ref><ref>{{cite web|title=More Evidence that Melatonin Eases Autism-Associated Insomnia|url=http://www.autismspeaks.org/science/science-news/more-evidence-melatonin-eases-autism-associated-insomnia|website=Autism Speaks|access-date=5 February 2015|archive-date=5 February 2015|archive-url=https://web.archive.org/web/20150205234816/http://www.autismspeaks.org/science/science-news/more-evidence-melatonin-eases-autism-associated-insomnia|url-status=live}}</ref>

===Strabismus===
According to several studies, there is a high prevalence of [[strabismus]] in autistic individuals, with rates 3–10 times that of the general population.<ref>{{Cite medRxiv | vauthors = Williams ZJ |title=Prevalence of Strabismus in Individuals on the Autism Spectrum: A Meta-analysis |year=2021 |medrxiv=10.1101/2021.07.13.21260452v1}}</ref>

===Tinnitus===
According to one study, 35% of people who are autistic would be affected by [[tinnitus]], which is much higher than in the general population.<ref>{{cite journal | vauthors = Danesh AA, Lang D, Kaf W, Andreassen WD, Scott J, Eshraghi AA | title = Tinnitus and hyperacusis in autism spectrum disorders with emphasis on high functioning individuals diagnosed with Asperger's Syndrome | journal = International Journal of Pediatric Otorhinolaryngology | volume = 79 | issue = 10 | pages = 1683–1688 | date = October 2015 | pmid = 26243502 | doi = 10.1016/j.ijporl.2015.07.024 }}</ref>

===Tourette syndrome===
The prevalence of [[Tourette syndrome]] among individuals who are autistic is estimated to be 6.5%, higher than the 2% to 3% prevalence for the general population. Several hypotheses for this association have been advanced, including common genetic factors and [[dopamine]], [[glutamate]] or [[serotonin]] abnormalities.<ref name=Zafeiriou/>

===Tuberous sclerosis===
[[Tuberous sclerosis]] is a rare genetic disorder that causes benign [[tumor]]s to grow in the brain as well as in other vital organs. It has a consistently strong association with the autism spectrum. One to four percent of autistic people also have tuberous sclerosis.<ref>{{cite journal | vauthors = Smalley SL | title = Autism and tuberous sclerosis | journal = Journal of Autism and Developmental Disorders | volume = 28 | issue = 5 | pages = 407–414 | date = October 1998 | pmid = 9813776 | doi = 10.1023/A:1026052421693 | s2cid = 36023695 }}</ref> Studies have reported that between 25% and 61% of individuals with tuberous sclerosis meet the diagnostic criteria for autism with an even higher proportion showing features of a broader [[pervasive developmental disorder]].<ref name="autism-prevalence">{{cite journal | vauthors = Harrison JE, Bolton PF | title = Annotation: tuberous sclerosis | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 38 | issue = 6 | pages = 603–614 | date = September 1997 | pmid = 9315970 | doi = 10.1111/j.1469-7610.1997.tb01687.x }}</ref>

=== Turner syndrome ===
[[Turner syndrome]] is an [[intersex]] condition wherein a person is born [[Phenotype|phenotypically]] female but with only one X chromosome or with X/XX [[Mosaic (genetics)|mosaicism]] instead of XX or XY chromosomes. One study found that 23% of girls with Turner syndrome who were included met criteria for a diagnosis of an autism spectrum disorder and the majority had "significant social communication difficulties."<ref>{{cite journal | vauthors = Wolstencroft J, Mandy W, Skuse D | title = Mental health and neurodevelopment in children and adolescents with Turner syndrome | journal = Women's Health | volume = 18 | pages = 17455057221133635 | date = December 6, 2022 | pmid = 36472167 | pmc = 9730007 | doi = 10.1177/17455057221133635 }}</ref>

===Vitamin deficiencies===
{{Expand section|date=November 2018}}
[[Vitamin deficiencies]] are more common in autism spectrum disorders than in the general population.

* ''[[Vitamin D]]'': [[Vitamin D deficiency]] was concerned in a German study 78% of hospitalized autistic population. 52% of the entire ASD group in the study was severely deficient, which is much higher than in the general population.<ref name="Vitamin D Deficiency in Adult Patie">{{cite journal | vauthors = Endres D, Dersch R, Stich O, Buchwald A, Perlov E, Feige B, Maier S, Riedel A, van Elst LT | display-authors = 6 | title = Vitamin D Deficiency in Adult Patients with Schizophreniform and Autism Spectrum Syndromes: A One-Year Cohort Study at a German Tertiary Care Hospital | journal = Frontiers in Psychiatry | volume = 7 | pages = 168 | year = 2016 | pmid = 27766084 | pmc = 5052261 | doi = 10.3389/fpsyt.2016.00168 | doi-access = free }}</ref> Other studies also show a higher rate of vitamin D deficiencies in ASDs.<ref name="Vitamin D Deficiency in Adult Patie"/>
* ''[[Vitamin B12]]'': The researchers found that, overall, B12 levels in the brain tissue of autistic children were three times lower than those of the brain tissue of children not affected by ASD. This [[vitamin B12 deficiency|lower-than-normal B12]] profile persisted throughout life in the brain tissues of patients with autism. These deficiencies are not visible by conventional blood sampling.<ref>{{Cite web | url=https://www.autismspeaks.org/science/science-news/study-vitamin-b12-levels-low-brains-affected-autism-or-schizophrenia | title=Science Blog &#124; Autism Speaks | access-date=2018-12-20 | archive-date=2018-08-05 | archive-url=https://web.archive.org/web/20180805052509/https://www.autismspeaks.org/science/science-news/study-vitamin-b12-levels-low-brains-affected-autism-or-schizophrenia | url-status=live }}</ref><ref>{{cite journal | vauthors = Zhang Y, Hodgson NW, Trivedi MS, Abdolmaleky HM, Fournier M, Cuenod M, Do KQ, Deth RC | display-authors = 6 | title = Decreased Brain Levels of Vitamin B12 in Aging, Autism and Schizophrenia | journal = PLOS ONE | volume = 11 | issue = 1 | pages = e0146797 | year = 2016 | pmid = 26799654 | pmc = 4723262 | doi = 10.1371/journal.pone.0146797 | doi-access = free | bibcode = 2016PLoSO..1146797Z }}</ref> As for the classic deficiency of vitamin B12, it would affect up to 40% of the population, its prevalence has not yet been studied in autism spectrum disorders. Vitamin B12 deficiency is one of the most serious.<ref>{{Cite web | url=https://www.ars.usda.gov/news-events/news/research-news/2000/b12-deficiency-may-be-more-widespread-than-thought/ | title=B12 Deficiency May be More Widespread Than Thought : USDA ARS | access-date=2018-12-20 | archive-date=2016-08-04 | archive-url=https://web.archive.org/web/20160804120552/http://www.ars.usda.gov/is/pr/2000/000802.htm | url-status=dead }}</ref>
* ''[[Vitamin B9]]'' (folic acid): Studies have been conducted regarding folic acid supplementation in autism in children. "The results showed that folic acid supplementation significantly improved certain symptoms of autism such as sociability, verbal / preverbal cognitive language, receptive language, and emotional expression and communication. In addition, this treatment improved the concentrations of folic acid, homocysteine and redox metabolism of standardized glutathione."<ref>{{cite journal | vauthors = Sun C, Zou M, Zhao D, Xia W, Wu L | title = Efficacy of Folic Acid Supplementation in Autistic Children Participating in Structured Teaching: An Open-Label Trial | journal = Nutrients | volume = 8 | issue = 6 | pages = 337 | date = June 2016 | pmid = 27338456 | pmc = 4924178 | doi = 10.3390/nu8060337 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Frye RE, Slattery J, Delhey L, Furgerson B, Strickland T, Tippett M, Sailey A, Wynne R, Rose S, Melnyk S, Jill James S, Sequeira JM, Quadros EV | display-authors = 6 | title = Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial | journal = Molecular Psychiatry | volume = 23 | issue = 2 | pages = 247–256 | date = February 2018 | pmid = 27752075 | pmc = 5794882 | doi = 10.1038/mp.2016.168 }}</ref>
* ''[[Vitamin A]]'': Vitamin A can induce mitochondrial dysfunction. According to a non-specific study on ASD: "Vitamin A and its derivatives, retinoids, are micronutrients necessary for the human diet in order to maintain several cellular functions of human development in adulthood as well as during aging ... Although it is either an essential micronutrient, used in clinical applications, vitamin A has several toxic effects on the redox environment and mitochondrial function. A decline in the quality of life and an increase in the mortality rate among users of vitamin A supplements have been reported. Although the exact mechanism by which vitamin A causes its deleterious effects is not yet clear ... Vitamin A and its derivatives, retinoids , disrupt mitochondrial function by a mechanism that is not fully understood."<ref name=pmid26078802>{{cite journal | vauthors = de Oliveira MR | title = Vitamin A and Retinoids as Mitochondrial Toxicants | journal = Oxidative Medicine and Cellular Longevity | volume = 2015 | pages = 140267 | year = 2015 | pmid = 26078802 | pmc = 4452429 | doi = 10.1155/2015/140267 | doi-access = free }}</ref>
* ''[[Zinc]]'': [[Zinc deficiency]] incidence rates in children aged 0 to 3, 4 to 9 and 10 to 15 years were estimated at 43.5%, 28.1% and 3.3% for boys and at 52.5%, 28.7% and 3.5% among girls.<ref>{{cite journal | vauthors = Yasuda H, Tsutsui T | title = Assessment of infantile mineral imbalances in autism spectrum disorders (ASDs) | journal = International Journal of Environmental Research and Public Health | volume = 10 | issue = 11 | pages = 6027–6043 | date = November 2013 | pmid = 24284360 | pmc = 3863885 | doi = 10.3390/ijerph10116027 | doi-access = free }}</ref>
* ''[[Magnesium]]'':  Incidence rates of [[magnesium deficiency]] in children aged 0 to 3, 4 to 9 and 10 to 15 years were estimated at 27%, 17.1% and 4.2% for boys and at 22.9%, 12.7% and 4.3% among girls.
* ''[[Calcium]]'': Incidence rates of [[Hypocalcaemia|calcium deficiency]] in children aged 0 to 3, 4 to 9 years and 10 to 15 years were estimated at 10.4%, 6.1% and 0.4% for boys and at 3.4%, 1.7% and 0.9% among girls.

It has been found that special diets that are inappropriate for children with ASD usually result in excessive amounts of certain nutrients and persistent vitamin deficiencies.<ref name=pmid26052041>{{cite journal | vauthors = Stewart PA, Hyman SL, Schmidt BL, Macklin EA, Reynolds A, Johnson CR, James SJ, Manning-Courtney P | display-authors = 6 | title = Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive | journal = Journal of the Academy of Nutrition and Dietetics | volume = 115 | issue = 8 | pages = 1237–1248 | date = August 2015 | pmid = 26052041 | doi = 10.1016/j.jand.2015.03.026 }}</ref>

===Other mental disorders===
[[Phobia]]s and other [[psychopathological]] disorders have often been described along with ASD but this has not been assessed systematically.<ref>{{cite journal | vauthors = Matson JL, Nebel-Schwalm MS | title = Comorbid psychopathology with autism spectrum disorder in children: an overview | journal = Research in Developmental Disabilities | volume = 28 | issue = 4 | pages = 341–352 | year = 2007 | pmid = 16765022 | doi = 10.1016/j.ridd.2005.12.004 | citeseerx = 10.1.1.697.4938 }}</ref>

==Notes==
{{reflist|group=note}}

== References ==
{{reflist|30em}}

{{Pervasive developmental disorders}}

[[Category:Autism]]
[[Category:Epidemiology]]
[[Category:Public health]]