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June 26, 2023

Psychiatric Co-morbidities of Eating Disorders

Psychiatric Co-morbidities of Eating Disorders

One of the most challenging center situations faced by a medical provider can be discerning when an eating disorder is present if accompanied by a co-morbid psychiatric disorder.

At times, clients will struggle overtly with weight or eating issues in the face of known mental illnesses including anxiety, depression, obsessive-compulsive disorder (OCD), and substance use. In fact, diagnostic criteria for depression include changes in appetite, eating, and weight. Individuals with OCD or anxiety may limit their food intake or binge eat in response to their emotional and physiologic states. Substance use can also alter appetite leading to changes in eating and weight. When first getting to know a client, symptom overlap may make it difficult for a medical practitioner to ascertain if changes in weight or issues with eating are secondary to such psychiatric diagnoses, or if the client has a primary eating disorder with comorbid diagnoses.

The known comorbidity rates of eating disorders and other mental health concerns are very high. In a national study of adolescents aged 13-18, more than 50% of adolescents diagnosed with an eating disorder met the criteria for another mental health diagnosis (Swanson, et al., 2011). Review of a large center database in Sweden showed that more than 70% of adults diagnosed with an eating disorder had comorbid mental health concerns (Ulfvebrand, et al., 2015). Similarly, the prevalence of substance and alcohol use disorders is greater in individuals diagnosed with eating disorders than in non-center populations (Hudson, et al., 2007; Kessler et al., 2013; Root et al., 2010). High rates of self-harm, borderline personality disorder, PTSD, and ADHD are also seen in clients with eating disorders.

It can be helpful for the non-psychiatric medical provider to remember that primary eating disorders are ego states. Patients with anorexia nervosa have an ego-syntonic illness. In very simple terms, for these clients, the eating disorder is part of who they are, and they cannot comprehend the need to change their behavior. Patients with bulimia nervosa or binge eating disorder have an ego-dystonic disorder. These clients view their illness as problematic and they often have great shame about their behavior. In both instances, when presenting to a medical provider, the client will not disclose their eating disorder thoughts but will seek help for medical concerns caused by the eating disorder behaviors.

Initially, it may be challenging for a medical provider to identify the treatment needs of a person struggling with issues around eating, weight, and mental health. A multi-disciplinary team evaluation can be helpful. Often, family members or mental health providers become concerned that an eating disorder is present when a client is in appropriate care for their presenting mental health concerns, but not making progress in improving weight or medical complications. Many clients with eating disorders have predating mental health issues but the weight or eating concerns are new, often a sign of co-occurring illnesses.

In some instances, weight restoration may be necessary before co-morbid diagnoses can be clarified. In a hallmark study of the physical and psychological impact of starvation, Ancel Keys showed that starvation dramatically alters mood and personality (Keys, et al., 1950). Patients who are starving can be irritable and have obsessional thinking about food and weight. For some clients, thoughts and depression may improve with nutritional rehabilitation. For other clients, however, weight restoration may unmask severe accompanying depression and even suicidality. As some individuals recover from an eating disorder, the loss of behaviors once used to manage distress can lead to increases in other behaviors such as self-harming and substance use.

How do we help these complicated clients? First, assess for suicidality and self-harm at every visit. Never forget that suicide is still a major cause of death in clients with eating disorders. Second, monitor and treat all medical complications, especially those related to starvation. For the starving brain, it does not matter which diagnosis is primary. The starving client must be refed and medically stabilized before medications can be expected to work and before the client is well enough to actively engage in therapy. For clients with a history of substance use, ongoing supervision and frequent drug testing allow providers to monitor for use which might impair recovery during treatment. Comorbid mental health issues must be identified, addressed, and monitored in parallel to treatment for the eating disorder.

The article Psychiatric Co-morbidities of Eating Disorders originally appeared on page 13 and 14 in The GEORGIA Pediatrician.


Hudson, J. I., Hiripi, E., Pope, H. G., Jr., & Kessler, R. C. (2007). The prevalence and correlates of eating disorders in the National Comorbidity Survey Replication. Biol Psychiatry, 61(3), 348-358. doi:10.1016/j.biopsych.2006.03.040 Kessler, R. C., Berglund, P. A., Chiu, W. T., Deitz, A. C., Hudson, J. I., Shahly, V., . . . Xavier, M. (2013). The prevalence and correlates of binge eating disorder in the World Health Organization World Mental Health Surveys. Biol Psychiatry, 73(9), 904-914. doi:10.1016/j.biopsych.2012.11.020 Keys, A., Brozek, J., Henschel, A., Mickelsen, O., & Taylor, H. L. (1950). The Biology of Human Starvation. . Minneapolis, MN: The University of Minnesota Press. Root, T. L., Pisetsky, E. M., Thornton, L., Lichtenstein, P., Pedersen, N. L., & Bulik, C. M. (2010). Patterns of co-morbidity of eating disorders and substance use in Swedish females. Psychol Med, 40(1), 105-115. doi:10.1017/ S0033291709005662 Swanson, S. A., Crow, S. J., Le Grange, D., Swendsen, J., & Merikangas, K. R. (2011). Prevalence and correlates of eating disorders in adolescents. Results from the national comorbidity survey replication adolescent supplement. Arch Gen Psychiatry, 68(7), 714-723. doi:10.1001/archgenpsychiatry.2011.22 Ulfvebrand, S., Birgegard, A., Norring, C., Hogdahl, L., & von Hausswolff-Juhlin, Y. (2015). Psychiatric comorbidity in women and men with eating disorders results from a large center database. Psychiatry Res, 230(2), 294- 299. doi:10.1016/j.psychres.2015.09.008

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