The Impact of Psychopharmacotherapy on Body Mass Index (BMI) of Children and Adolescents with Bipolar Disorder

Objectives: To assess the impact of psychopharmacotherapy on BMI among bipolar children and adolescents with bipolar disorders, and to assesses the change of BMI after the treatment discontinuation.

Methods: This retrospective cohort study used General Electric electronic medical records to identify children and adolescents with bipolar diagnosis (18 years or younger) and prescribed atypical antipsychotics (AT), mood stabilizers (MS) or antidepressants (AD). A minimum of 6 months of baseline period was applied prior to the first bipolar diagnosis defined as the index diagnosis date. After excluding individuals who had bipolar diagnosis or psychotropic prescription during the baseline period, and without body mass index (BMI) measures in the pre-index or follow-up period; the individuals in the study cohort were followed up to 3, 6, 9 and 12 months to determine the effect of treatment regimens on Body Mass Index (BMI). Those who discontinued the treatment within the 12 month post index period were continuously followed for an additional 3, 6, 9, and 12 months to observe whether the BMI patients gained during the treatment could return to the baseline. The repeated measures mixed models were applied to account for the nesting effect of multiple BMI measures available to each individual, and estimate the effect of treatment and subsequent discontinuation on BMI after adjusting for the baseline BMI, socio-demographics, comorbidities and psychotherapy.

Results: The cohort consisted of 2,299 individuals in the treatment and 1,265 individuals in the discontinuation phase of the study. MS monotherapy regimen was associated with a steady increase in BMI over time (3 months: 0.11 kg/m2, 6 months: 0.09 kg/m2, 9 months: 0.09 kg/m2 and 12 months: 0.089 kg/m2. As compared to children and adolescents who were on MS monotherapy, those who were on AD monotherapy, AT+MS, AT+AD or MS+AD had similar pattern of change of BMI. AT monotherapy was the only regimen associated with more BMI gain (3 months: 0.244 kg/m2, 6 months: 0.10 kg/m2, 9 months: 0.07 kg/m2, 12 months: 0.05 kg/m2) at all time points than MS monotherapy. After the treatment discontinuation, most patients’ BMI stayed on the level during the treatment and did not return to the baseline level. The proportion of children and adolescents who were overweight/obese (≥85 percentile), 12 months after treatment discontinuation, was significantly higher (53.49%) than that at the start of the treatment (51.03%). The change in BMI after the treatment discontinuation was neither associated with the type of treatment the individuals received in the treatment phase nor was it associated with time elapsed from the treatment discontinuation. Being older and having lower BMI at the end of the treatment was associated with relative more reduction of BMI after the treatment discontinuation at all follow-up periods.

Conclusion: Significant increase in BMI among children was observed in all children and adolescent who were on all psychotropic regimens. The magnitude of BMI increase was positively associated with the duration of the exposure. Atypical antipsychotics was the treatment associated with the most significantly increase in BMI. BMI gained during treatment is, on average, not reversible after discontinuation of treatment. Extra effort is needed to minimize the weight gain during the treatment to prevent the long term cardiovascular consequence of being overweight and obese.