Treatment of Obsessive-Compulsive Disorder with Comorbid Eating Disorders

by Rachel C. Leonard, Ph.D. and Bradley C. Riemann, Ph.D.

This article was initially published in the Summer 2013 edition of the OCD Newsletter

Obsessive-compulsive disorder (OCD) and eating disorders often co-occur, and while well-established treatments exist for each of these disorders on their own, there is little research to suggest what clinicians should do when faced with an individual who has both OCD and an eating disorder. Evidence-based treatments are typically examined using randomized controlled trials, which often include participants with only one disorder, follow disorder-specific treatment protocols, and have stringent guidelines regarding medication use throughout the research study. For OCD, evidence-based treatments include cognitive behavioral therapy (CBT) emphasizing exposure and response prevention (ERP), the use of serotonin reuptake inhibitors (SRIs; specifically clomipramine and selective SRIs), or a combination of these therapies (1). For eating disorders, evidence-based treatments include CBT emphasizing eating monitoring and cognitive restructuring (for both anorexia nervosa [AN] and bulimia nervosa [BN]), the use of fluoxetine (for BN), and weight restoration (for AN).

ERP is highly effective for OCD, either alone or in combination with SRIs(2), and has been used with some success to treat BN (3). Pilot studies also suggest that exposure techniques may be helpful for patients with AN (4), Emerging research now suggests that ERP may also be an option when simultaneously treating co-occuring OCD and eating disorders, supplemented with additional evidence-based interventions, such as medication management and weight restoration (for AN).

In a recently published article, Simpson et al.(5) described the application of ERP techniques to both OCD and eating disorder symptoms and presented the outcomes from patients treated with this approach in a residential treatment program at Rogers Memorial Hospital. Participants were 56 adults with OCD and a co-occurring eating disorder who were admitted to the program between June 2006 and July 2011, and who completed all measures of interest at admission and discharge. This included self-report assessments of OCD symptom severity (Yale-Brown Obsessive-Compulsive Scale – Self Report [Y-BOCS-SR]), eating disorder symptom severity (Eating Disorder Examination Questionnaire [EDE-Q]), and depression symptom severity (Beck Depression Inventory-II [BDI-II]). In addition, body mass index (BMI; kg/m2) was calculated at admission and discharge. The average duration of treatment was 57 days. Of the 56 participants, 23 were diagnosed with AN, 14 were diagnosed with BN, and 19 were diagnosed with eating disorder not otherwise specified (ED-NOS).

Patients received 15-20 hours per week of ERP for their OCD and eating disorder symptoms (see below for a description). Additional treatment elements included cognitive restructuring techniques, regular meetings with a dietician (to monitor adherence to the meal plan and monitor weight), psychiatric medications and meetings with a psychiatrist to monitor the use of medications, experiential therapy, and social work support. Social workers met with patients individually twice per week to provide supportive psychotherapy and discharge planning. They also conducted weekly family sessions for psycho-educational purposes and provided a weekly process group.

How is ERP Implemented for OCD and for Eating Disorders?

For OCD symptoms, a detailed exposure hierarchy tailored to each patient’s symptoms is created. Each exposure is designed evoke an obsessive thought, impulse, or image that will cause a challenging but manageable level of anxiety that the patient is asked to experience without engaging in any corresponding compulsions (i.e., rituals). The goal of exposure therapy is for the patient to experience habituation, which is a decrease in anxiety experienced due to the passage of time. Therefore, through repeated exposure trials, patients learn that their anxiety will decrease without the need to engage in avoidance behaviors or rituals. The exposure hierarchy contains a detailed list of exposures across a wide range of anticipated anxiety levels. Patients start with less challenging exposures and work up to more challenging exposures. For example, a patient with fears about contracting HIV through touching surfaces may start by working on an exposure to touch a table in her home that only her spouse has touched without then washing her hands and, over the course of treatment, work up to an exposure to shake hands with individuals at an HIV resource center without washing. In addition to specific exposure exercises, patients are asked to resist engaging in their rituals, especially when their anxiety is at a manageable level.

ERP procedures are used in a similar manner to address eating disorder symptoms. A hierarchy of feared foods is created, and as part of the patient’s meal plan, feared foods are incorporated gradually, starting with less feared foods and working up to more challenging foods. While this is similar to challenge foods incorporated into many treatment plans for individuals with eating disorders, exposures for those with both eating disorders and OCD are done in a very detailed and graduated manner consistent with an exposure hierarchy. In addition, exposures are included to address anxiety regarding eating situations, such as eating in public. Exposures may also be used to address concerns with body shape, such as viewing disliked body parts in a mirror, wearing normally fitting rather than loose clothing, or trying on swim suits at a local mall. Similar to ritual prevention for OCD, patients are expected to complete exposures without any compensatory behaviors related to their eating disorder, such as vomiting, restricting at a future meal, excessively exercising, overeating when faced with negative emotions, comparing their body to others’ bodies, covering up with a blanket, counting calories or other food quantities (e.g., grams of fat), or cutting their food into very small pieces. In addition to specific exposure exercises, patients are asked to resist engaging in their identified compensatory behaviors, especially when their anxiety is at a manageable level.

How Well Does this Approach Work?

Simpson and colleagues (6) found that participants entered treatment in the severe range on the measures of OCD symptom severity and depression symptom severity, and had scores indicative of significant eating disorder pathology. Participants experienced statistically significant and clinically meaningful reductions in OCD severity, eating disorder severity, and depression severity after receiving treatment.

Regarding improvement in OCD symptoms, 80% of participants responded to treatment (indicated by a reduction of 25 % on the Y-BOCS-SR) and 50% of participants had only mild or minimal OCD symptoms at discharge (indicated by a Y-BOCS-SR score of 12 or less). These rates of improvement are similar to those reported in studies of ERP that recruited patients with OCD and no comorbid eating disorder and with similar OCD severity at baseline (7). Participants with each of the three eating disorders experienced significant improvement in OCD symptoms; however, those with BN experienced significantly more improvement than did participants with AN. Participants with ED-NOS did not significantly differ from those with AN or BN, with change scores falling in between these two groups.

Participants also experienced significant decreases in eating disorder severity. This was the case for all three eating disorder diagnoses, although, as with OCD symptoms, participants with BN experienced significantly greater improvement in eating disorder severity than did those with AN. Those with ED-NOS improved more than those with AN and less than those with BN, but this difference was not significant in either comparison. Further, participants experienced significant improvements in depression severity, despite the severe level of depression symptoms at admission and the fact that depression was not an area of significant focus in treatment.

Conclusions and Implications

Due to the numerous treatment elements and naturalistic design, we cannot definitively conclude that the observed improvements were due to the ERP component rather than other aspects of treatment (e.g., structured eating, residential setting, social support, medication changes, etc.). However, it is unlikely that the results are due to medication, since the majority of participants (89%) were taking medication upon admission, with only a few participants beginning new classes of medications throughout the course of their treatment. In addition, there is a very low response rate in OCD to nonspecific interventions (8), suggesting that the improvement was due specifically to ERP. It is likely that some of the improvement in eating disorder symptoms was due to non-ERP treatment components.

These results suggest that the incorporation of ERP techniques as part of a multimodal treatment approach can be highly effective in improving symptoms of both OCD and eating disorders.


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  6. Simpson et al (2013).
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  8. Huppert, J. D., Schultz, L. T., Foa, E. B., Barlow, D. H., Davidson, J. R., Gorman, J. M., et al. (2004). Differential response to placebo among patients with social phobia, panic disorder, and obsessive-compulsive disorder. American Journal of Psychiatry, 161, 1485-1487. Simpson et al., 2008.