Influence of depressive and eating disorders on short- and long-term course of weight after surgical and nonsurgical weight loss treatment.

Objective: To investigate the influence of depressive and eating disorders on short- and long-term weight loss after surgical and non-surgical weight-reduction treatment. Covariations between the disorders were considered.

Method: In a longitudinal naturalistic study, current diagnoses at baseline and lifetime diagnoses of depressive and eating disorders were assessed in participants who were undertaking a very-low-calorie diet (n = 250) and in bariatric surgery patients (n = 153). Lifetime diagnosis of a mental disorder was defined as presence of a mental disorder only in the past. Body weight was measured at baseline, 1 year after baseline, and 4 years after baseline. Mental comorbidity was assessed through use of standardized interviews at baseline. A structural equation modeling procedure was applied to test the associations between course of weight and mental disorders. Analyses were based on the intention to treat samples. Missing values were replaced by use of multiple imputation procedures.

Results: Neither depression nor eating disorders were associated with weight changes at the 1-year follow-up, but a specific effect emerged for bariatric surgery patients after 4 years: depression (current and lifetime) predicted smaller body mass index loss, whereas lifetime diagnosis of eating disorder was associated with greater weight loss.

Conclusions: Individuals who report depressive disorders prior to bariatric surgery should be monitored more closely in order to identify patients who would benefit from additional therapy with the goal of improving weight-loss outcome.