Mood and eating disorders in obese patients referred for bariatric surgery: prevalence rates and impact on post-surgical outcome.

Introduction Obese patients seeking bariatric intervention exhibit high rates of mental disorders and psychopathological traits that could impact weight and mental health outcomes after bariatric surgery. Objectives The first objective of these two studies was to report the lifetime prevalence of mood, eating, and anxiety disorders in two Italian samples of obese patients seeking bariatric surgery. In addition, we aimed to investigate in a prospective and naturalistic setting whether the presence of different psychiatric disorders or certain psychopathological traits were associated with post-surgical outcome. Methods In the first prospective study, clinical data and psychiatric comorbidities of obese bariatric patients (n=99) were collected during the presurgical evaluation by participating psychiatrists. After surgery, weight, obesity-related comorbidities and psychiatric status were monitored during a 1-year follow-up. In the second study, medical records from a different and larger sample of pre-bariatric patients (n=871) were retrieved and reviewed for psychiatric diagnoses and clinical information. Subsequently, patients will be contacted by telephone for a follow-up survey to collect data on post-surgical weight and psychiatric outcomes 5-15 years after surgery. Results The prevalence of psychiatric disorders was 80% in the first and 55% in the second study. Binge eating disorder (BED) was the most frequent single diagnosis in both studies (52% and 28%), followed by mood disorders, especially belonging to the bipolar spectrum (40% and 33%), and panic disorder (37% and 16%). In the first study, 34 patients completed follow-up; of these, 24% showed inadequate weight loss (i.e., excess BMI loss ≤53%) at 1 year. These patients had more frequent lifetime mood disorders (p=0.011) and BED (p=0.044) than subjects with adequate weight loss, and they scored higher on both clinician-administered and self-report scales assessing impulsivity and emotional dysregulation. The latter two psychopathological traits were found to be predictors of reduced weight loss at 1-year after surgery on logistic regression analysis. Conclusion Our study confirms the high rates of psychiatric comorbidities in bariatric patients. After surgery, patients with mood disorders and BED have been shown to exhibit worse weight outcomes than patients without these comorbidities. Furthermore, this is the first study to show an association between the presence of marked impulsivity, emotional dysregulation and inadequate weight loss after bariatric surgery. Future longer follow-up studies with larger samples are urgently needed.