Neuropsychological Functioning and Temperament in Obsessive-compulsive Disorder and Eating Disorders
Abstract: In recent years a growing body of evidence has led some researchers to hypothesize that eating disorders (EDs) are best conceptualized as a form of obsessive-compulsive disorder (OCD). This recent research highlights the functional, phenomenological, and neurobiological similarities between the two disorders as well as high levels of co-occurrence, patterns of familial transmission, and selective response to pharmacologic and behavioral treatments. However, few studies have compared EDs and OCD directly. This investigation sought to expand upon previous research by exploring temperament and neuropsychological variables, which may influence the phenomenology of these disorders and investigating whether those variables may represent a common underlying vulnerability. Three groups of approximately 20 women were recruited: an ED group, an OCD group, and a healthy control group. All participants were diagnosed using a semi-structured interview. They completed several self-report questionnaires as well as a battery of neuropsychological tests designed to assess inhibition, cognitive flexibility, decision-making and learning. The results suggest several temperamental similarities between ED and OCD groups including heightened levels of harm avoidance, attentional impulsivity, perfectionism, and emotional avoidance compared to controls. While there were notable similarities between the two clinical groups there were also differences. The ED group reported greater levels of body checking than the OCD group and while overall perfectionism was similar, the ED group evidenced greater concern over mistakes whereas the OCD group reported greater doubts about actions. Several neuropsychological similarities were also found between the two clinical groups, including comparable performance on tasks of response inhibition, cognitive flexibility, and verbal learning. While the ED group evidenced less advantageous decision-making compared to the OCD group, multivariate models including both temperament and decision-making indicated that temperament, but not decision-making, differentiated the two clinical groups. Overall, these results suggest important similarities in temperament and neuropsychological functioning between EDs and OCD, potentially reflecting a common underlying vulnerability. Findings also point to a few specific differences in personality and symptom expression, in addition to definitional Axis I symptoms, which elucidate important distinctions between these two groups.