Purpose: This aims of the study were (i) to describe the exposure to antipsychotic medications over a 4-year period experienced by a cohort of children who initiated antipsychotic treatment before their 6th birthday; and (ii) to identify variables associated with the risk of antipsychotic exposure.

Methods: Children were identified who initiated an index episode of antipsychotic treatment before their 6th birthday in the fee-for-service Medicaid programme in Florida (USA).  With the use of claims data, the medication utilisation of these children was tracked during the year before and the 4 years following the start of their index episodes (pre-index and four post-index periods).  Generalised estimating equations were used to identify variables associated with the risk of additional days of antipsychotic exposure.

Results: 528 children were included in the cohort.  The mean total number of days of exposure was 821.9 (+/- 431.9), representing 56.3% of all days during the four post-index periods.  The mean days of exposure to combinations of antipsychotics and other classes of psychotherapeutic medications were 623.8 +/- 447.6 days.  Children with primary diagnoses of pervasive developmental disorders and affective disorders were at greater risk of additional days of exposure than children with attention deficit/hyperactivity disorder.  Exposure tended to be greater among children with indicators of clinical complexity including the presence of secondary diagnoses and the use of other classes of psychotherapeutic medications in addition to antipsychotics.

Conclusions: Exposure to antipsychotic mediations was extensive.  Although these children may have had complex and severe problems, additional research is urgently needed on the benefits and risks of long-term antipsychotic exposure among very young children.