Background: Approximately 20% of bariatric surgery candidates are excluded for reasons of mental health. All bariatric patients undergo a pre-operative assessment of suitability, including a mental health assessment. There are no NICE guidelines as to what level of mental illness is considered an exclusion; it is generally regarded that unstable mental health is a contraindication to surgery. The main reason is concern regarding adherence to essential lifestyle changes post-surgery.
Methods: We retrospectively analysed data from 100 consecutive patients who had bariatric surgery at Kings College Hospital in 2017. Patients were divided into groups based on their pre-operative history of mental illness. We also analysed whether they had been actively treated for mental health problems. The primary outcome looked at was percentage weight loss at 12 months.
Results: The main finding was that patients with a single mental illness diagnosis (depression or anxiety) lost significantly less weight, compared to those with no history of mental illness (23.4% vs. 29.2%; P=0.005). Conversely, those with multiple or more complex mental health diagnoses, such as bipolar and/or schizophrenia, achieved good weight loss comparable to the group without mental health diagnoses. Further analysis revealed that the groups with untreated mental health diagnoses appeared to lose less weight following bariatric surgery, compared to patients being actively treated.
Conclusion: The study indicates that not all mental health diagnoses are associated with a worse outcome following bariatric surgery. It is untreated pre-operative mental illness who have the worst weight loss outcomes. Patients with treated mental health diagnoses, have similar outcomes to those without a mental health diagnosis. These results suggest more attention needs to be given to whether a mental health condition is being actively treated. The results also potentially indicate a need to revise guidelines on suitability for bariatric surgery, in relation to mental health.