Psychiatric Factors and Weight Loss Patterns Following Gastric Bypass Surgery in a Veteran Population

Background Although pre-surgical psychological evaluations are commonly administered to patients considered for weight loss surgeries, the value of these evaluations for predicting weight loss success has been questioned. In this study, we addressed this issue by examining patient’s total number of psychiatric indicators rather than individual psychological factors as predictors of weight loss/weight regain. Methods Sixty adult veterans completed gastric bypass surgery or laparoscopic gastric banding after completing a multidisciplinary evaluation for surgical clearance, including a psychological assessment. Patients were subsequently followed for 24 month to examine changes in weight, body mass index, and risk of weight regain. Results Nearly three fourths of the sample carried either a single (40.0%) or multiple psychiatric diagnoses (33.4%). Nearly half (47.5%) of the sample ceased losing weight after 1 year, with 29.5% regaining weight after this point. Neither psychiatric nor biomedical factors effectively predicted 1-year weight loss totals; however, we observed a significant linear relationship between the number of psychiatric factors and post-1-year weight changes (r=0.33, p=0.01). After adjusting for demographic and biomedical factors, patients with two or more psychiatric diagnoses were found to be significantly more likely to experience weight loss cessation or weight regain after 1-year (OR= 6.4, 95% CI=1.3–12.4) relative to those with zero or one psychiatric diagnosis. Conclusions Assessing mental health factors in terms of the total number of psychiatric conditions improved the prediction of weight loss surgery outcomes in this veteran sample. An expanded model for understanding how psychological factors may affect weight loss surgery may improve the utility of pre-bariatric psychological assessments.