Patient, Physician and Organizational Influences on Variation in Prescribing Behavior

Abstract   Physicians face the choice of over 20 ingredients when prescribing antipsychotic medications. Personalized prescribing is of great importance given considerable patient heterogeneity in antipsychotic treatment response. Using Pennsylvania’s Medicaid data, IMS Health’s HCOSTM database, and the AMA Masterfile, this paper studies variation in psychiatrists’ prescribing of antipsychotics and the influence of patient characteristics, physician characteristics, and organizational features on the diversity/concentration of antipsychotic prescribing. There was substantial variability in antipsychotic prescribing concentration, with share for most preferred ingredient ranging from 16%-85%. On average, psychiatrist prescribing behavior was relatively diversified; however, 11% of psychiatrists wrote an average of 55% of their prescriptions for their most preferred ingredient. Female physicians and those with smaller shares of disabled or serious mental illness patients had more concentrated prescribing behavior. Our findings indicate that even among specialties regularly prescribing a therapeutic category, some rely heavily on a small number of agents.