Introduction: Obesity-associated psychopathological co-morbidities have a negative impact on quality of life. Roux-en-Y gastric bypass surgery (RYGB) has been shown to ameliorate psychological health, however, the underlying mechanisms are not fully understood. Changes in gastrointestinal and central neuroendocrine signalling have been postulated as mediators of psychological and eating behaviour changes following RYGB. Here we assess the impact of subcutaneous infusions of three anorexigenic gut hormones glucagon-like peptide-1, oxyntomodulin and peptideYY (GOP) on the psychological health of obese diabetic patients.
Method: In this prospective cohort study, 27 obese diabetic patients were recruited and randomized to GOP (n=16) or saline (n= 11) infusion for 4 weeks. We also studied 16 patients who underwent RYGB. A set of validated questionnaires were used to measure psychological health, eating psychopathology, and quality of life pre- and post-intervention. Results were analysed using two-way ANOVA followed by post-hoc analysis using the Bonferroni method to correct for multiple corrections.
Results: Both GOP and RYGB showed an improvement of health-related quality of life related to weight loss. There was a significant increase in restrained eating and a significant reduction in external eating in the GOP group, an improvement on reward and punishment sensitivity assessed by the Behavioural Inhibition System and Behavioural Activation System (BIS/BAS) scales after GOP compared with the saline group. There was a significant improvement in the RYGB group the Power of Food Scale, a questionnaire that measures an individuals motivation to consume highly palatable foods. These results emphasise the effectiveness of the surgical intervention in ameliorating obesity-related symptoms whilst providing substantial long-lasting weight-loss effects.
Conclusion: The improvement in the reward sensitivity post-GOP warrants further research using longer-term studies. The augmented secretion of anorexigenic hormones post RYGB in its own may not be the only mediator for the favourable improvement in psychological health seen after RYGB.