An analysis of the slowdown in growth of spending for psychiatric drugs, 1986-2008

Abstract

Objective: This study analyzed recent trends in spending on psychiatric prescription drugs and underlying factors that served as drivers of these changes.

Methods: Data were collected from the MarketScan Commercial Claims and Encounters Database (1997-2008), Substance Abuse and Mental Health Services Administration spending estimates (1986-2005), and the Medical Expenditure Panel Survey (1997-2007). The trends in medication spending derived from the data were decomposed into three categories: percentage of enrollees who used psychiatric medications, days supplied per user, and cost per day supplied.

Results: The average annual rate of growth in expenditures per enrollee slowed from 18.5% in 1997-2001 to 6.3% in 2001-2008. A decline in the growth rate of cost per day supplied, from 8% to 2%, accounted for 49% of the overall decline in spending growth, and a decline in the growth of the percentage of enrollees who used medication, from 7% to 2%, contributed 41% to the overall decline. There was a smaller change in days supplied per user, from 3% to 2%, that contributed 10% to the overall decline. The increased entry of generic medications, which constituted 70% of all psychiatric prescriptions by 2008, particularly generic antidepressants, was a key contributor to the slower growth in costs.

Conclusions: Past high growth in psychiatric drug spending arising from growth in utilization of branded medications has declined significantly, which may have implications for access and new product investment.