Editing Eating disorder (section)

=== Genetics ===
Numerous studies show a [[genetic predisposition]] toward eating disorders.<ref name="RB">{{cite journal |vauthors=Klump KL, Kaye WH, Strober M |title=The evolving genetic foundations of eating disorders |journal=The Psychiatric Clinics of North America |volume=24 |issue=2 |pages=215–25 |date=June 2001 |pmid=11416922 |doi=10.1016/S0193-953X(05)70218-5}}</ref><ref>{{cite journal |vauthors=Mazzeo SE, Bulik CM |title=Environmental and genetic risk factors for eating disorders: what the clinician needs to know |journal=Child and Adolescent Psychiatric Clinics of North America |volume=18 |issue=1 |pages=67–82 |date=January 2009 |pmid=19014858 |pmc=2719561 |doi=10.1016/j.chc.2008.07.003}}</ref> Twin studies have found a slight instances of genetic variance when considering the different criterion of both anorexia nervosa and bulimia nervosa as endophenotypes contributing to the disorders as a whole.<ref name="CT2" /> An individual who is a first degree relative of someone who has had or currently has an eating disorder is seven to twelve times more likely to have an eating disorder themselves.<ref name="CT5">{{cite journal |vauthors=Patel P, Wheatcroft R, Park RJ, Stein A |title=The children of mothers with eating disorders |journal=Clinical Child and Family Psychology Review |volume=5 |issue=1 |pages=1–19 |date=March 2002 |pmid=11993543 |doi=10.1023/A:1014524207660 |s2cid=46639789}}</ref> Twin studies also show that at least a portion of the vulnerability to develop eating disorders can be inherited, and there is evidence to show that there is a genetic locus that shows susceptibility for developing anorexia nervosa.<ref name="CT5" /> About 50% of eating disorder cases are attributable to genetics.<ref>{{cite journal |vauthors=Trace SE, Baker JH, Peñas-Lledó E, Bulik CM |s2cid=33773190 |title=The genetics of eating disorders |journal=Annual Review of Clinical Psychology |volume=9 |pages=589–620 |date=2013 |pmid=23537489 |doi=10.1146/annurev-clinpsy-050212-185546}}</ref> Other cases are due to external reasons or developmental problems.<ref>{{Cite book |title=College of the Overwhelmed: The Campus Mental Health Crisis and What to Do About It |vauthors=Kadison R |publisher=Jossey-Bass |year=2004 |isbn=978-0-7879-8114-3 |location=San Francisco |page=[https://archive.org/details/collegeofoverwhe0000kadi/page/132 132] |url=https://archive.org/details/collegeofoverwhe0000kadi/page/132}}</ref> There are also other neurobiological factors at play tied to emotional reactivity and impulsivity that could lead to binging and purging behaviors.<ref>{{Cite book |title=Mental Health Issues & the University Student |vauthors=Iarovici D |publisher=Johns Hopkins University Press |year=2014 |isbn=978-1-4214-1238-2 |location=Baltimore |page=[https://archive.org/details/mentalhealthissu0000iaro/page/104 104] |url=https://archive.org/details/mentalhealthissu0000iaro/page/104}}</ref>

[[Epigenetics]] mechanisms are means by which environmental effects alter gene expression via methods such as [[DNA methylation]]; these are independent of and do not alter the underlying DNA sequence. They are heritable, but also may occur throughout the lifespan, and are potentially reversible. Dysregulation of [[dopaminergic]] [[neurotransmission]] due to epigenetic mechanisms has been implicated in various eating disorders.<ref name="RC">{{cite journal |vauthors=Frieling H, Römer KD, Scholz S, Mittelbach F, Wilhelm J, De Zwaan M, Jacoby GE, Kornhuber J, Hillemacher T, Bleich S |title=Epigenetic dysregulation of dopaminergic genes in eating disorders |journal=The International Journal of Eating Disorders |volume=43 |issue=7 |pages=577–83 |date=November 2010 |pmid=19728374 |doi=10.1002/eat.20745 |doi-access=free}}</ref> Other candidate genes for epigenetic studies in eating disorders include [[leptin]], [[pro-opiomelanocortin]] (POMC) and [[brain-derived neurotrophic factor]] (BDNF).<ref>{{cite journal |vauthors=Campbell IC, Mill J, Uher R, Schmidt U |title=Eating disorders, gene-environment interactions and epigenetics |journal=Neuroscience and Biobehavioral Reviews |volume=35 |issue=3 |pages=784–93 |date=January 2011 |pmid=20888360 |doi=10.1016/j.neubiorev.2010.09.012 |s2cid=24599095}}</ref>

There has found to be a genetic correlation between anorexia nervosa and OCD, suggesting a strong etiology.<ref name="cab">{{cite journal |vauthors=Levinson CA, Brosof LC, Ram SS, Pruitt A, Russell S, Lenze EJ |date=August 2019 |title=Obsessions are strongly related to eating disorder symptoms in anorexia nervosa and atypical anorexia nervosa |journal=Eating Behaviors |volume=34 |pages=101298 |doi=10.1016/j.eatbeh.2019.05.001 |pmc=6708491 |pmid=31176948}}</ref><ref name=":19">{{cite journal | vauthors = Meier M, Kossakowski JJ, Jones PJ, Kay B, Riemann BC, McNally RJ | title = Obsessive-compulsive symptoms in eating disorders: A network investigation | journal = The International Journal of Eating Disorders | volume = 53 | issue = 3 | pages = 362–371 | date = March 2020 | pmid = 31749199 | doi = 10.1002/eat.23196 | s2cid = 208214719}}</ref><ref name=":24">{{cite journal | vauthors = Lee EB, Barney JL, Twohig MP, Lensegrav-Benson T, Quakenbush B | title = Obsessive compulsive disorder and thought action fusion: Relationships with eating disorder outcomes | journal = Eating Behaviors | volume = 37 | pages = 101386 | date = April 2020 | pmid = 32388080 | doi = 10.1016/j.eatbeh.2020.101386 | s2cid = 218585620}}</ref> First and second relatives of probands with OCD have a greater chance of developing anorexia nervosa as genetic relatedness increases.<ref name=":24"/>