Prevalence of obesity and weight change during treatment in patients with bipolar I disorder.

BACKGROUND: Obesity is a major public health concern in the United States and its prevalence is increasing. Individuals with bipolar disorder tend to be overweight, and their treatment may exacerbate obesity and increase the risk of concurrent medical disease in this population.

METHOD: This retrospective report from the Pittsburgh Study of Maintenance Therapies in Bipolar Disorder examines the prevalence of overweight (body mass index [BMI] = 25.0-29.9) and obesity (BMI > or = 30.0) in 50 consecutive subjects with bipolar I disorder (DSM-IV) and evaluates weight change during acute treatment and the first year of maintenance treatment.

RESULTS: At entry into the study, 34 (68%) of the patients in this sample with bipolar disorder were obese or overweight. The prevalence of obesity was high (16 [32%] of the 50 patients in our sample). The number of previous depressive episodes contributed to the likelihood of being overweight or obese at study entry. During the trial, most of the weight gain occurred during acute treatment rather than during maintenance treatment. During acute treatment, the amount of increase of BMI was positively related to the score on the Hamilton Rating Scale for Depression and negatively related to the score on Bech-Rafaelsen Mania Scale. There was a negative relationship between BMI and tendency to gain weight, during both acute and maintenance treatment.

CONCLUSION: The high prevalence of obesity in subjects with bipolar disorder emphasizes the need for specific treatment strategies and programs for weight control for these individuals. The minimal weight gain during the maintenance phase, the relationship of acute depressive episodes to weight gain, and the fact that stabilization on maintenance medication may facilitate the participation in specific interventions for weight loss provide additional support for the practice of maintenance treatment.