Psychiatric Comorbidity Among Eating Disorders and Obsessive-Compulsive Disorder and Underlying Shared Mechanisms and Features: An Updated Review

Eating disorders (EDs) are highly comorbid with obsessive-compulsive disorder (OCD), with comorbidity rates as high as 41%. In the current review, we summarize the literature regarding the prevalence of ED-OCD comorbidity. We also identify and review the literature assessing shared features (i.e., shared characteristics or symptoms) and mechanisms (i.e., variables that may explain ED or OCD symptoms) of EDs and OCD. Potential shared features of EDs and OCD include age of onset, course of illness, obsessions, compulsions and ritualistic behaviors, and thought action fusion. Shared mechanisms that may explain ED-OCD comorbidity include genetic and neurobiological mechanisms, anxiety and fear, repetitive negative thinking, perfectionism, intolerance of uncertainty, distress tolerance, and impulsivity. Based on these shared features and mechanisms, a theoretical conceptualization of ED and OCD comorbidity is developed, and outline considerations for assessment, differential diagnosis, treatment, and future research regarding ED-OCD comorbidity are described.