• bariatric surgery
• bipolar disorder
• eating behaviours
• obesity

Background: Obesity is one of the most important multifactorial diseases of our time; it can be associated with many psychiatric disorders, one of the main is bipolar disorder (BD). Some of the elements that mediate the role of BD and obesity are problematic eating behaviours (PEB) such as emotional eating (EE), food addiction (FA), grazing (GZ) and night eating (NE). They are also studied in samples of candidates for bariatric surgery where they may affect their severe obesity. The main goal of the study is to investigate the presence of eating behaviours, in a sample of bipolar patients and in a sample of candidates for bariatric surgery, searching a correlation among them, the presence of impulsivity and BMI and analyzing the possible role of mood disorders. The secondary objective is to evaluate whether these features also occur in subjects who do not have a full-blown mood disorder but subthreshold symptoms of the mood spectrum.
Methods: 50 euthymic bipolar patients (BD) and 200 subjects undergoing psychiatric evaluation before bariatric surgery (BS) were recruited at the University Hospital of Pisa. Patients were clinically interviewed and diagnoses were made according to DSM-5 criteria by means of structured clinical interview (SCID-5). Anamnestic informations were collected and a battery of psychometric tests was administered: Emotional Eating Scale (EES), Yale Food Addiction Scale (YFAS), Eating Disorder Inventory (EDI-2), Eating Disorder Questionnaire (EDE-Q), Night Eating Scale (NES), Grazing Questionnaire (GQ), Mood Spectrum Self-Report (MOOD-SR), Barratt Impulsive Scale (BIS).
Results: The only PEB that correlated with BMI and with impulsivity was GZ. GQ correlated more strongly than the others with EDI-2 and EDE-Q. We divided BS in those with a mood disorder (MD, n=48) and those without (w/o MD, n=152), comparing scales between BD vs MD, BD vs w/o MD and MD vs w/o MD. We observed no difference for EE, FA, GZ in the three groups. Impulsivity was significantly greater in BD and MD vs w/o MD; NE was greater in BD and MD vs w/o MD while EDI-2 and EDE-Q were significantly greater in MD vs the other two groups. The correlation with MOOD-SR in the w/o MDs confirmed the connection of PEBs also with subthreshold symptoms of the mood spectrum, especially for the depressive or rhythmicity domains.
Conclusions: These evidences show that bipolar and severely obese people have a high prevalence of PEB. In BD, GZ and impulsivity have the greatest relevance while in BS the presence of a mood disorder led to higher scores in all scales. PEB could have a major influence on obesity in patients with mood disorders and aggravate their psychopathology. On the contrary, the presence of a mood disorder (even if subthreshold) in obese subjects is an element to be carefully researched in so far as it worsens the seriousness and the post-surgical bariatric course, mainly because of its greater susceptibility to elements such as emotional eating, food addiction, high impulsivity, grazing and night eating, which can worsen the seriousness of the clinical picture, affect the response to bariatric surgery and the subsequent prognosis.