Eating Disorders and Obsessive-Compulsive Disorder

Eating disorders and obsessive-compulsive disorder (OCD) share a number of common traits. In both, strong beliefs fuel ritualistic behaviors. And when the behaviors aren't performed, anxiety is very high. Many have wondered whether OCD and eating disorders share common origins as well as common symptoms (see complete symptoms of eating disorders and symptoms of OCD).

Links between Obsessive-Compulsive Disorder and Eating Disorders

OCD is common in eating disorders. In both anorexia and bulimia, OCD may be present in as many as 25% to 40% of cases. Many eating disorder behaviors look like compulsive behaviors driven by fears about body shape. The fear of gaining weight may lead to a powerful ritual of binging and purging (bulimia nervosa), or to restricting calories to an unhealthy level (anorexia nervosa).

But researchers have also found that those with eating disorders often have obsessive-compulsive behaviors that have nothing to do with food or body issues. Behaviors common in OCD that those with eating disorders might do include very frequent hand-washing due to a fear of germs, or insisting on checking that a door is locked many times before going to bed.

Evidence exists that OCD is associated with longer duration of eating disorders, even for those who do not resist treatment. It may be that ritualistic thoughts and behaviors indicate more firmly-set beliefs that take longer to challenge and change successfully.

Food-Related OCD Behaviors in Eating Disorders

The classic example of obsessions and compulsions in eating disorders is the woman (or man) with anorexia who organizes life around calorie counting. She will use much of her spare time thinking of how many calories she has eaten, how many she will eat, and in what forms she will eat them.

For example, she may always eat the same foods (perhaps an apple and a precisely-measured cube of cheese) in the same places (in the chair facing the window) at the same time (12:08 p.m., or some other exact minute). This person's obsession is with food and what it may do to her, and her compulsive behavior takes all the uncertainty out of eating. It therefore soothes fear.

Bulimic rituals can also be compulsive. For example, a person might eat only certain foods in a certain order. But again, these food-related compulsions can lead to others: Cleaning up after purging may include cleaning the toilet, the bathroom, and/or the sink. A shower may punctuate the entire process.

Newer Research on EDs and OCD

Early research testing those with eating disorders versus those with OCD alone suggests that those with eating disorders actually struggle with stronger tendencies toward perfectionism, overestimation of threats, and intolerance for uncertainty, among other traits. These are commonly thought to be associated with OCD; that those with disordered eating had even more deeply-entrenched leanings seems surprising. However, the sample of disordered-eating subjects in the study may have contained some who could also have been diagnosed with OCD; researchers did not have the data to determine this.

Further research on perfectionism hints that those with eating disorders may be more likely to have a diagnosis of obsessive-compulsive personality disorder (OCPD) rather than OCD. In OCPD, obsessions and compulsive behaviors are not as dominant as perfectionism. A person with OCPD demands that things be done "the right way" as defined by that person. Rules and control are paramount, whether there are repetitive and compulsive behaviors or not.