The rapid growth in the use of antipsychotic medications and their related costs have resulted in states developing programs to measure, monitor, and insure their beneficial relevance to public program populations. One such program developed in the state of Florida has adopted an evidence-based approach to identify prescribers with unusual psychotherapeutic prescription patterns and track their utilization and costs among Florida Medicaid patients. This study reports on the prescriber prescription and cost patterns for adults and children using three measures of unusual antipsychotic prescribing patterns: (1) two antipsychotics for 60 days (2AP60), (2) three antipsychotics for 60 days (3AP60), and (2) two antipsychotics for 90 or more days (2AP90). We find that over the four-year study period there were substantial increases in several aspects of the Florida Medicaid behavioral drug program. Overall, for adults and children, patient participation increased by 29 percent, the number of prescriptions grew by 30 percent, and the number of prescribers that wrote at least one prescription grew 48.5 percent, while Medicaid costs for behavioral drugs increased by 32 percent. But the results are highly skewed. We find that a relatively small number of prescribers account for a disproportionately large share of prescriptions and costs of the unusual antipsychotic prescriptions. In general, the top 350 Medicaid prescribers accounted for more than 70 percent of the unusual antipsychotic prescriptions, and we find that this disparity in unusual prescribing patterns appears to be substantially more pronounced in adults than in children prescribers. For just the top 13 adult and children prescribers, their practice patterns accounted for 11 percent to 21 percent of the unusual prescribing activity and, overall, these 13 top prescribers accounted for 13 percent of the total spent on antipsychotics by the Florida Medicaid program and 9.3 percent of the total expenditure by the state for all drugs. Our findings suggest that a strategy to monitor and ensure patient safety and prescribing patterns that targets a relatively small number of Medicaid providers could have a substantial benefit and prove to be cost effective.