Effect of Psychopharmacotherapy on Body Mass Index Among Children and Adolescents with Bipolar Disorders.

OBJECTIVE: To assess the long-term effect of all treatment options for pediatric bipolar disorders on body mass index (BMI) and to explore individual characteristics associated with less BMI increase during psychotropic medication exposures. METHODS: A retrospective cohort study was conducted by using the 1995 to 2010 General Electric Electronic Medical Record database. Individuals aged 18 years or younger who had a new bipolar disorder episode were identified. Treatment exposure was defined based on the medication regimens patients received, which include atypical antipsychotic (AT) monotherapy, mood stabilizer (MS) monotherapy, antidepressant (AD) monotherapy, AT+MS polytherapy, AT+AD polytherapy, MS+AD polytherapy, and no treatment. Both treatment exposure and BMI were coded as time varying, which could change from month to month. According to the duration of treatment and the availability of BMI measures, individuals were followed for up to 3, 6, 9, and 12 months since the treatment initiation. Repeated-measures mixed models were applied to compare the impact of different medication regimens and the length of drug exposure on BMI after adjusting for the baseline BMI, sociodemographic factors, comorbidities, and psychotherapy. RESULTS: A total of 2299 treated and 4544 untreated children and adolescents who met the inclusion criteria were identified. Analysis using repeated-measures mixed models showed that those on AT monotherapy (the reference group) had a gradually diminished, but statistically significant, monthly increase in BMI during all durations of drug exposure (3 months: 0.36 kg/m2, 6 months: 0.20 kg/m2, 9 months: 0.17 kg/m2, and 12 months: 0.16 kg/m2). As compared with AT monotherapy, the magnitude of increase in BMI associated with MS, AD monotherapy, and no treatment was significantly less at all time points, indicating less steep slopes of BMI change over time compared with AT monotherapy, especially during the short-term exposure. The combinations of AT with other psychotropic medications (ATMS, ATAD) were associated with a similar BMI increase as AT monotherapy. Individual characteristics found to be associated with a less increase in BMI during psychotropic medication exposure were being younger and having a higher baseline BMI. CONCLUSION: The long-term use of atypical antipsychotics, both as monotherapy or in combination with other psychotropic medications in children and adolescents with bipolar disorder, was associated with a steady and cumulative increase in BMI.