The geography of antidepressant, antipsychotic, and stimulant utilization in the United States.

This paper analyzes local and regional geographic variability in the use of antidepressant, antipsychotic and stimulant medications in the United States. Using a data set that covers 60% of prescriptions written in the United States, we find that use of antidepressants in three digit postal codes ranged from less than 1% of residents to more than 40% residents. Stimulant and antipsychotic use exhibited similar levels of local geographic variability. A Kulldorf Spatial Scan identified clusters of elevated use of antidepressants (RR 1.46; p<0.001), antipsychotics (RR 1.42; p<0.001), and stimulants (RR 1.77; p<0.001). Using a multilevel model, we find that access to health care, insurance coverage and pharmaceutical marketing efforts explain much of the geographic variation in use.