Does the overvaluation of shape and weight predict initial symptom severity or treatment outcome among patients with binge eating disorder

Binge eating disorder (BED), currently a provisional diagnosis in the fourth edition of the Diagnostic and Statistical Manual (DSM) of Mental Disorders (American Psychiatric Association, 1994), is characterized by recurrent binge eating episodes in the absence of extreme weight-control behaviors. The two formally recognized eating disorders in DSM-IV, anorexia nervosa and bulimia nervosa, include a criterion for the overvaluation of shape or weight, or an “undue influence of body weight or shape on self-evaluation” (American Psychiatric Association, 1994).1 While a similar criterion is not currently included for the diagnosis of BED, studies implicate the overvaluation of shape and weight as a critical clinical distinction between binge eaters and obese individuals without the disorder.2 With the fifth edition of the DSM scheduled for publication in 2012, several recent studies have examined the potential utility of the overvaluation of shape and weight as an indicator of clinical status for individuals with BED, as well as the ability of this construct to inform the revision of diagnostic criteria for BED. Previous research observed significant relationships between the overvaluation of shape and weight, eating disorder pathology, and psychosocial functioning among patients with BED.3–8 These findings have led to questions of whether the overvaluation of shape and weight should be a required diagnostic criterion for BED, or rather a diagnostic specifier that conveys additional clinical information about symptom severity. Although a number of studies have examined the presenting clinical characteristics of individuals with BED in relation to the overvaluation of shape and weight, only one study has evaluated the effect of this construct on treatment outcome. Masheb and Grilo (2008) categorized patients with BED into those with “clinical” versus “subclinical” overvaluation of shape and weight, and examined whether these subtypes predicted or moderated response to guided self-help treatments based on cognitive behavioral therapy (CBT) or behavioral weight loss.9 Post-treatment, participants with clinical overvaluation reported higher levels of eating disorder pathology as measured by global score on the Eating Disorder Examination-Questionnaire (EDE-Q) than those participants with subclinical overvaluation. While overvaluation of shape and weight significantly predicted one aspect of treatment outcome in this study, the construct was not found to moderate the effects of either guided self-help intervention. The purpose of the current study was: (1) to replicate previous research relating the overvaluation of shape and weight to eating disordered and other psychiatric symptoms (i.e., depression, self-esteem, and eating disorder pathology); and (2) to determine whether overvaluation affected treatment outcome among a sample of patients with BED enrolled in a randomized controlled trial.10 Based on the extant literature, we hypothesized that patients with BED endorsing overvaluation of shape and weight would report greater depression and eating disorder pathology, and lower self-esteem than patients without overvaluation. We also hypothesized that, in keeping with the findings of Masheb and Grilo (2008), patients with BED endorsing overvaluation of shape and weight would show smaller improvements from the treatment interventions, consisting of group behavioral treatment plus individual CBT and/or fluoxetine, than those without overvaluation.