Treating comorbid obsessive-compulsive disorder and eating disorders can be complex as OCD symptoms such as rigidity, perfectionism, and reassurance seeking can disrupt typical ED interventions such as meal planning. Additionally, the content of a patient’s obsessions in OCD can shift to different categories in their life, including ED recovery (e.g., intrusive thoughts that they are going to relapse). To address the challenges of treating comorbid OCD and EDs, it is important to promote flexibility in various aspects of meal planning such as incorporating a variety of foods, being flexible with meal times, meal prepping, and promoting mindfulness and self-compassion. Cognitive techniques such as cognitive restructuring can be used to help patients identify and challenge rigid and perfectionistic thinking. Gradual exposure to flexibility can also be used to help patients learn to tolerate and manage their anxiety. A collaborative approach involving patients in the meal-planning process can also be helpful in reducing rigidity and promoting a more active role in decision-making.

Some components of commonly used, empirically supported eating disorder treatments (CBT-E and FBT) may not be suitable for patients who also have OCD. These include aspects of parental control in FBT, collaborative weighing, self-monitoring and eating schedules/meal plans, and psychoeducation about food and weight. Achieving weight gain is particularly difficult in anorexia nervosa due to fear and preoccupation with weight, eating and “becoming fat.” Low body weight and malnourishment tends to increase anxiety and obsessionality, so weight gain early on is paramount, especially for individuals with this co-occurring presentation. Through clinical observations, patients have reported that FBT may aggravate OCD symptoms, such as preoccupation with numbers and exactness, and expanding obsessionality to concerns about exercise/movement and other topics within the morality domain of OCD. The lack of control and greater uncertainty that an adolescent experiences while completing FBT may be related to increased OCD symptomatology and poor treatment outcomes.