Editing Informed consent (section)

==Assessment==
Informed consent can be complex to evaluate, because neither expressions of consent, nor expressions of understanding of implications, necessarily mean that full adult consent was in fact given, nor that full comprehension of relevant issues is internally digested.<ref>{{cite journal | vauthors = Murray B | title = Informed Consent: What Must a Physician Disclose to a Patient? | journal = AMA Journal of Ethics | date=Jul 2012 | url = https://journalofethics.ama-assn.org/article/informed-consent-what-must-physician-disclose-patient/2012-07 | volume = 14 | issue = 7 | pages = 563–566 | doi=10.1001/virtualmentor.2012.14.7.hlaw1-1207 | pmid = 23351294 | access-date = 13 Sep 2020| doi-access = free | url-access = subscription }}</ref> Consent may be implied within the usual subtleties of human communication, rather than explicitly negotiated verbally or in writing. For example, if a doctor asks a patient to take their blood pressure, a patient may demonstrate consent by offering their arm for a blood pressure cuff. In some cases consent cannot legally be possible, even if the person protests he does indeed understand and wish. There are also structured instruments for evaluating capacity to give informed consent, although no ideal instrument presently exists.<ref>{{Cite journal |last=Sturman |first=E |date=November 2005 |title=The capacity to consent to treatment and research: A review of standardized assessment tools |url=https://linkinghub.elsevier.com/retrieve/pii/S0272735805000498 |journal=Clinical Psychology Review |language=en |volume=25 |issue=7 |pages=954–974 |doi=10.1016/j.cpr.2005.04.010|pmid=15964671 |url-access=subscription }}</ref>

Thus, there is always a degree to which informed consent must be assumed or inferred based upon observation, or knowledge, or legal reliance. This especially is the case in sexual or relational issues. In medical or formal circumstances, explicit agreement by means of signature—normally relied on legally—regardless of actual consent, is the norm. This is the case with certain procedures, such as a "[[do not resuscitate]]" directive that a patient signed before onset of their illness.<ref>{{Cite journal |last=Woodruff |first=William A. |title=Letting Life Run Its Course: Do-Not-Resuscitate Orders and Withdrawal of Life-Sustaining Treatment |url=https://scholarship.law.campbell.edu/cgi/viewcontent.cgi?referer=&httpsredir=1&article=1085&context=fac_sw |journal=Scholarly Works |pages=7 |via=Scholarly Repository @Campbell University School of Law}}</ref>

Brief examples of each of the above:
# A person may verbally agree to something from fear, perceived social pressure, or psychological difficulty in asserting true feelings. The person requesting the action may honestly be unaware of this and believe the consent is genuine, and rely on it. ''Consent is expressed, but not internally given.''
# A person may claim to understand the implications of some action, as part of consent, but in fact has failed to appreciate the possible consequences fully and may later deny the validity of the consent for this reason. ''Understanding needed for informed consent is present but is, in fact (through ignorance), not present.''
# A person signs a [[legal release]] form for a [[medical procedure]], and later feels he did not really consent. Unless he can show actual misinformation, the release is usually persuasive or conclusive in law, in that the clinician may rely legally upon it for consent. ''In formal circumstances, a written consent usually legally overrides later denial of informed consent (unless obtained by misrepresentation)''.
# Informed consent in the U.S. can be overridden in emergency medical situations pursuant to [[21CFR50.24]], which was first brought to the general public's attention via the controversy surrounding the study of [[Polyheme]].