OBJECTIVES : - To compare the prevalence of adverse events (AEs) among children and adolescents taking single and multiple antipsychotics (APs).

METHODS : - A retrospective observational cohort study was conducted using 2016-2018 Mississippi Medicaid administrative claims data. Inclusion criteria were prescription fills for APs during study period, age 18 years or less, continuous enrollment 6 months pre- and 12 months post-AP start date. Multiple AP users were defined as those who had at least 45 days of continuous use of 2 or more APs. Beneficiaries were excluded if they had AP use in the 6 month baseline period. Logistic regression and generalized linear models were used to assess the relationships among type of AP use (multiple or single) and AEs.

RESULTS : - The study cohort included 124 multiple AP users and 821 single AP users. During the 12-month post-period, 13.6% of the single AP users had an AE compared to 19.3% of the multiple AP users. The most common AE was suicidal ideation (9.0% for single AP users and 16.1% for multiple AP users). Controlling for age, gender, race, and pharmacy plan, multiple AP users had 2.16 times the odds [95% CI: (1.19-3.90)] of suicidal ideation as single AP users. Multiple AP users had higher rates for tachycardia (2.1% for single AP users and 4.0% for multiple AP users [OR = 1.73, 95% CI: 0.58 – 5.92] and any AE [Odds Ratio (OR) = 1.51, 95% CI: 0.89 – 2.57], but these were not statistically significant.

CONCLUSIONS : - Children and adolescents taking multiple APs have significantly greater odds of suicidal ideation compared to those taking a single AP. Even though the analysis was limited by low sample size, the results highlight the safety concerns associated with multiple AP use. Further research needs to be conducted in a larger sample to confirm these findings.