Treatment of obesity with liraglutide in bipolar disorder: a case report

Bipolar disorder (BD) is a chronic, severe mental illness frequently complicated by metabolic disturbances such as obesity, insulin resistance and dyslipidaemia. We report the case of a 57-year-old man with Bipolar I Disorder and class III obesity (BMI 47.7 Kg/m²) whose mood episodes were tightly linked to weight fluctuations. patients' psychiatric history began in 1986 with a manic episode and recurrent depressive and manic relapses over nearly four decades, often provoked by weight-loss attempts. In February 2024, he was admitted for initiation of liraglutide under close psychiatric monitoring, given prior episodes of mania triggered by dietary interventions. At baseline, he exhibited moderate illness severity (CGI = 4), insulin resistance (HOMA-IR = 6.19), dyslipidaemia and sedentary habits. Liraglutide was titrated from 0.6 mg to 1.8 mg over three weeks. During the weight-loss intervention, and temporally after liraglutide titration to 1.8 mg/day, he developed a manic episode (YMRS = 30), prompting an increase in risperidone and addition of gabapentin alongside continuation of mood stabilizers. His manic symptoms remitted within one week, allowing discharge with liraglutide 1.8 mg, risperidone 3 mg, valproic acid and lamotrigine. Over subsequent outpatient follow-up at the target liraglutide dose (3 mg/day), he lost 6.5 kg more (total Δ weight = - 7 kg), his HOMA-IR improved to 5.78 and glycemic and lipid parameters stabilized without further mood destabilization. This case illustrates the bidirectional interplay between metabolic regulation and mood stability in BD, highlights the need for close psychiatric monitoring during structured weight-loss interventions in clinically vulnerable patients, and supports integrated multidisciplinary care when initiating anti-obesity treatments in patients with severe mental illness.