Editing Retrograde amnesia (section)

=== Nutritional deficiency ===
RA has been found among alcohol-dependent patients who have [[Korsakoff's syndrome]].<ref name="De_Bellis_2000">{{cite journal | vauthors = De Bellis MD, Clark DB, Beers SR, Soloff PH, Boring AM, Hall J, Kersh A, Keshavan MS | title = Hippocampal volume in adolescent-onset alcohol use disorders | journal = The American Journal of Psychiatry | volume = 157 | issue = 5 | pages = 737–44 | date = May 2000 | pmid = 10784466 | doi = 10.1176/appi.ajp.157.5.737 | s2cid = 1668456 }}</ref> Korsakoff's syndrome patients develop retrograde amnesia due to a [[thiamine]] deficiency (lack of vitamin B1).<ref name="McEntee_1990">{{cite journal | vauthors = McEntee WJ, Mair RG | title = The Korsakoff syndrome: a neurochemical perspective | journal = Trends in Neurosciences | volume = 13 | issue = 8 | pages = 340–4 | date = August 1990 | pmid = 1699320 | doi = 10.1016/0166-2236(90)90146-2 | s2cid = 31404753 }}</ref> Also, chronic alcohol use disorders are associated with a decrease in the volume of the left and right hippocampus.<ref name="De_Bellis_2000"/>

These patients' regular diet consists mostly of hard alcohol intake, which lacks the necessary nutrients for typical development and maintenance.<ref name="McEntee_1990" /> Therefore, after a prolonged time consuming primarily alcohol, these people undergo memory difficulties and ultimately develop RA. However, some of the drawbacks of using Korsakoff patients to study RA is the progressive nature of the illness and the unknown time of onset.<ref name="Squire_1995"/>