A National Institutes of Health-funded study of how policies restricting pharmaceutical promotions to physicians affect medication prescribing found that physicians in academic medical centers prescribed fewer promoted drugs – and more non-promoted drugs in the same classes – following policy changes restricting marketing activities.

The analysis covered 16.1 million prescriptions; while the decline observed was modest as a percentage of prescriptions, proportionally small changes can represent thousands of prescriptions.

“There has long been concern that drug marketing to physicians might influence their prescribing, including – and maybe especially – for psychiatric drugs,” says Michael Schoenbaum, Ph.D, senior advisor for mental health services, epidemiology and economics at the National Institute of Mental Health and coauthor of the paper.

During the period studied – January 2006 to June 2012 – 19 academic medical centers across five states (California, Illinois, Massachusetts, New York and Pennsylvania) instituted policies restricting “detailing,” a common promotional tool used by pharmaceutical marketers that can include free samples and meals. The study compared prescribing by the 2,126 physicians affiliated with the centers with restrictions with that of 24,593 physicians with similar backgrounds and prescribing habits in the same states.

The study authors reported changes in prescribing in terms of changes in the market share of detailed and non-detailed drugs. The mean market share of detailed drugs in academic medical centers prior to the restrictions was 19.3 percent. Over the period of study, the market share of detailed drugs prescribed declined by 8.7 percent in the restricted cohort, to a market share of roughly 17.6 percent. The changes were statistically significant for six of the eight drug classes studied and for all drugs in the aggregate.

More information on the study and analysis is available on the NIH website.