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July 19, 2019

OCD and Eating Disorders: Untangling the Diagnostic Web

The Veritas Collaborative Symposium on Eating Disorders offers medical, mental, behavioral and other healthcare professionals the opportunity to learn from renowned experts in the eating disorder field. Steven Tsao, Ph.D., a keynote speaker at this year’s symposium, walks us through the complex comorbid relationship between obsessive-compulsive disorder (OCD) and eating disorders and how to properly diagnose and treat these two disorders.

Rachel* is preoccupied with thoughts of heart disease, restricts her diet to “healthy” foods, exercises most days of the week for an hour, and frequently weighs herself to see if she’s nearing overweight status. When her planned meals get changed suddenly, she becomes overwhelmed with anxiety and seems driven to find a way to atone for such changes by altering her exercise routine, even on days that she doesn’t want to work out. She frequently asks friends and family about her health, hoping to feel reassured, but routinely ends up feeling unfulfilled by their responses instead. She’s lost weight and says it feels better to be underweight than risk being “fat.”

Does Rachel have an eating disorder? Does Rachel have OCD? Does she have both?

Even for experienced clinicians, these distinctions can seem blurry and difficult to tease apart. Many patients with eating disorders report very high anxiety and use rigid, repeated, and at times, senseless behaviors to help cope with such distress. Determining an accurate diagnosis and a clear understanding of the function of these behaviors can be a tricky endeavor, fraught with pitfalls, but it is also imperative to ensure that the right treatment interventions are used to help patients like Rachel.

There are a few strategies to help distinguish OCD and eating disorders, but it should be pointed out that for those suffering like Rachel and their loved ones, nothing will replace a thorough evaluation by a trained professional.

First, identifying the fear that lies at the core of Rachel’s anxiety can help shine a light in one direction. Most people with eating disorders express high anxiety around gaining weight or being fat, with core fears around being judged, rejected, or devalued for such physical changes. Most people with OCD describe core fears of dying or living a meaningless existence due to overwhelming doubt, ruined relationships, or inability to contribute to society. Thus, determining if a patient’s anxiety is focused on the consequences of weight, shape, and body image is a reasonable start to clarifying the diagnostic picture.

Second, the level of conviction that patients like Rachel hold about their beliefs can shed further light on an accurate diagnosis. For people with eating disorders, their beliefs about how they gain weight, the importance that weight or shape has upon their self-worth and their worth to others, and the predictive power weight gain has about their future often feel in-line with their overall belief system. In other words, they see these thoughts as accurate descriptions of the way the world works. For people with OCD, they often recognize that their worries are senseless, excessive, or unlikely to occur. They describe these thoughts as being different from their genuine selves and recognize them as glitches in their otherwise rational thought patterns. However, it should be noted that such insight can vacillate from being very rational in some moments to seemingly delusional when experiencing an acute obsession.

Lastly, the role of malnutrition and semi-starvation should be considered as it can further muddy the waters. Studies have shown that a semi-starved state of chronic malnutrition can in and of itself produce obsessive thinking about food, ritualized eating behaviors, and mood swings including anxiety. As such, helping underweight patients reach a reasonable level of physical health is an important step in determining whether these seemingly psychiatric symptoms remit with proper nutrition.

While there are no easy answers or fool-proof shortcuts to distinguishing OCD and eating disorders, untangling these two disorders is an important step towards ensuring appropriate treatment. While the suggestions outlined here are a good start towards separating these illnesses, a thorough evaluation by a trained professional is the only way to truly ensure an accurate diagnosis. If you are in search of a knowledgeable professional that specializes in OCD, please use the Find Help tool at the International OCD Foundation website (

*Name changed for privacy

About the Author

Dr. Steven Tsao is the co-founder of the Center for Anxiety & Behavior Therapy, a specialty center in suburban Philadelphia focused on evidence-based care and treatment dissemination. He has been invited to give talks, workshops, and in-service trainings on managing OCD in eating disorder populations across various levels of care. Dr. Tsao will be a keynote speaker at the 8th Annual Veritas Collaborative Symposium on Eating Disorders, presenting Obsessed and Hungry: Recognizing and Managing OCD in Eating Disorder Treatment.