The Link Between Anorexia Nervosa and Obsessive-Compulsive Disorder (OCD)

Exploring the Overlap in Thoughts, Behaviors, and Treatment Implications

Anorexia nervosa (AN) is often misunderstood as a disorder centered around food and weight — but for many individuals, it is deeply rooted in obsessional thinking, compulsive rituals, and a drive for perfection and control. These traits significantly overlap with Obsessive-Compulsive Disorder (OCD), a condition marked by intrusive thoughts and compulsive behaviors intended to reduce anxiety.

Research continues to reveal strong connections between anorexia and OCD — both in symptom expression and in underlying neurobiology. Understanding this relationship can help improve diagnosis, tailor treatment strategies, and reduce the suffering caused by these intertwined conditions.

What Is Obsessive-Compulsive Disorder (OCD)?

OCD is a psychiatric disorder characterized by:

• Obsessions: Recurrent, intrusive thoughts, images, or urges that cause distress (e.g., contamination, harm, order).

• Compulsions: Repetitive behaviors or mental acts performed to neutralize the distress caused by obsessions (e.g., hand washing, counting, checking).

OCD is not about being “tidy” or “neat” — it is a debilitating condition that can interfere significantly with daily life.

Anorexia Nervosa at a Glance

Anorexia nervosa is a serious eating disorder involving:

• Restriction of food intake leading to significantly low body weight.

• Intense fear of gaining weight, even when underweight.

• Distorted body image or self-worth excessively influenced by body shape and weight.

There are two subtypes:

• Restricting Type: Primarily restrictive behaviors.

• Binge-eating/Purging Type: Includes episodes of bingeing and/or purging.

Shared Features Between Anorexia Nervosa and OCD

1. Obsessional Thinking

• Individuals with anorexia often experience persistent thoughts about food, body shape, weight, and control.

• These thoughts are intrusive, anxiety-provoking, and difficult to dismiss — similar to classic OCD obsessions.

2. Compulsive Rituals

• Rigid food rules, meal-time rituals, and exercise routines are common in AN.

• Like compulsions in OCD, these behaviors serve to reduce distress — but are not rational or adaptive.

Examples include:

• Cutting food into precise shapes or sizes

• Eating foods in a specific order

• Excessive weighing or checking

• Compensatory behaviors like over-exercising or purging

3. Perfectionism and Cognitive Rigidity

• Both disorders are associated with maladaptive perfectionism and difficulty shifting mental sets (cognitive inflexibility).

• Many individuals experience black-and-white thinking — for example, “If I don’t follow my food plan perfectly, I’ve failed.”

4. Neurobiological Overlap

• Imaging studies suggest that both OCD and AN involve dysregulation in the cortico-striatal-thalamo-cortical circuit, which plays a role in habit formation and error detection.

• Serotonin imbalance is also implicated in both conditions, which may partially explain their high comorbidity and response to certain medications.

How Common Is the Co-Occurrence of OCD and Anorexia?

• Lifetime prevalence of OCD in individuals with anorexia is estimated between 25–69%, depending on the sample and subtype (Halmi et al., 2003; Kaye et al., 2004).

• OCD symptoms often precede the onset of anorexia, suggesting a potential risk factor.

• Comorbidity is more common in the restricting subtype of AN.

• Individuals with both OCD and AN often have longer illness duration, more severe symptoms, and greater treatment resistance (Meier et al., 2015).

Important Differences Between OCD and Anorexia

Despite the similarities, these are distinct diagnoses. Key differences include:

Feature Anorexia Nervosa OCD Primary Focus Food, body image, weight control Varied obsessions (e.g., contamination, morality) Insight Often limited insight or ego-syntonic (behaviors feel "right") Usually ego-dystonic (behaviors feel intrusive) Physical Consequences Severe malnutrition, organ damage, hormonal disruption Physical health may be less directly impacted Motivation Often tied to self-worth, identity, or fear of weight gain Driven by need to neutralize distress from intrusive thoughts

Treatment Considerations for Co-Occurring OCD and AN

When both disorders are present, treatment should be integrated, flexible, and trauma-informed. Key approaches include:

1. Cognitive Behavioral Therapy (CBT)

• CBT-E (Enhanced CBT for Eating Disorders) is the gold standard for AN and can be adapted to address OCD symptoms.

• Traditional CBT for OCD, which includes Exposure and Response Prevention (ERP), may be introduced once the patient is medically stable.

2. Nutritional Rehabilitation First

• In anorexia, malnutrition itself worsens OCD symptoms due to cognitive impairment and anxiety.

• Food reintroduction and weight restoration are prerequisites for effective psychological treatment.

3. SSRIs

• Selective Serotonin Reuptake Inhibitors (SSRIs), such as fluoxetine and sertraline, are commonly used in OCD and may reduce obsessional thoughts in AN.

• Higher doses may be needed for OCD-related symptoms and should be prescribed with caution in underweight patients (Kaye et al., 2001).

4. Family-Based Therapy (FBT)

• Especially effective in adolescents, FBT can help parents take the lead in supporting recovery, while also learning how to respond to obsessive-compulsive behaviors around food.

5. Targeting Perfectionism and Rigidity

• Skills from Dialectical Behavior Therapy (DBT) and Acceptance and Commitment Therapy (ACT) may help reduce rigidity and increase distress tolerance.

Final Thought

Anorexia nervosa and OCD often walk side by side — intertwined in thought patterns, compulsions, and coping strategies. Recognizing their overlap can improve diagnosis, reduce shame, and lead to more effective, individualized treatment.

If you or someone you love is living with both disorders, know that healing is possible. It begins with understanding the function behind the behavior — and offering tools to meet those needs in safer, life-affirming ways.

References

• Halmi, K. A., Tozzi, F., Thornton, L. M., Crow, S., Fichter, M. M., Kaplan, A. S., ... & Bulik, C. M. (2005). The relation among perfectionism, obsessive-compulsive personality disorder and obsessive-compulsive disorder in individuals with eating disorders. International Journal of Eating Disorders, 38(4), 371–374.

• Kaye, W. H., Bulik, C. M., Thornton, L., Barbarich, N., & Masters, K. (2004). Comorbidity of anxiety disorders with anorexia and bulimia nervosa. American Journal of Psychiatry, 161(12), 2215–2221.

• Meier, S. M., Bulik, C. M., Thornton, L. M., & Mattheisen, M. (2015). Comorbidity between eating disorders and anxiety disorders: Evidence from a Danish national register study. Psychological Medicine, 45(3), 524–534.

• Steinglass, J. E., Walsh, B. T., & Stern, Y. (2006). Set shifting deficit in anorexia nervosa. Journal of the International Neuropsychological Society, 12(3), 431–435.

• Kaye, W. H., Bailer, U. F., Frank, G. K., Wagner, A., & Henry, S. E. (2005). Brain imaging of altered reward and emotion in anorexia nervosa. CNS Spectrums, 10(8), 579–586.

• Zastrow, A., Kaiser, S., Stippich, C., Walther, S., Herzog, W., & Tchanturia, K. (2009). Neural correlates of impaired cognitive-behavioral flexibility in anorexia nervosa. American Journal of Psychiatry, 166(5), 608–616.