Many studies have shown a link between eating disorders and obsessive-compulsive disorder (OCD). People with eating disorders are more likely to have OCD than the rest of the population and people with OCD are more likely to develop eating disorders than other people. Some researchers have even gone so far as to suggest that eating disorders should be regarded as a sub-group of OCD. A study of 2,971 female eating disorder inpatients compared those with OCD to those without and found that those with OCD suffered more severe eating disorder symptoms. However, in both the short and medium term both groups responded equally well to treatment.
Cumella, Edward J., Kally, Zina and Wall, A. David - Treatment responses of inpatient eating disorder women with and without co-occuring obsessive-compulsive disorder Eating Disorder March-April 2007, 15(2), 111-124