The Definition and Prevalence of Pediatric Psychotropic Polypharmacy

OBJECTIVES: Using increasingly stringent criteria, this study evaluated the prevalence of psychotropic polypharmacy among children on the basis of duration of overlap between two or more psychotropic medications. METHODS: The prevalence of psychotropic polypharmacy was defined as receiving ≥ 14 days, ≥ 30 days, ≥ 60 days, and ≥ 90 days of overlapping psychotropic prescription fills. Descriptive analysis was used to compare the prevalence findings on the basis of multistate Medicaid data involving children six to 18 years of age. A sensitivity analysis was also conducted to explore the extent to which the cross-sectional operational definitions of polypharmacy used in the published literature identified patients who were prescribed psychotropic combinations on a long-term basis. RESULTS: The analysis revealed that 282,910 children had at least one psychotropic prescription fill in 2005. Of these patients, 28.8% received psychotropic combinations for at least 14 consecutive days. The observed rate of polypharmacy dropped to 27.2% with 30 days of overlap and to 20.9% with 60 days of overlap. Using a 60-day overlap in psychotropic drugs as a cutoff between short-term and long-term polypharmacy, analyses showed that 14%-46% of patients identified by cross-sectional definitions as receiving polypharmacy had likely received combination treatment on a temporary rather than on a long-term basis. In addition, cross-sectional definitions failed to identify 18%-44% of patients classified as receiving long-term polypharmacy (≥ 60-day overlap). CONCLUSIONS: The observed rate of polypharmacy dropped with increasingly stringent operational definitions for polypharmacy. The findings suggest that considerable differences arise when comparing rates of polypharmacy across studies with inconsistent operational definitions.