Effects of pharmaceutical promotion on adherence to the treatment guidelines for depression

We sought to examine the impact of direct-to-consumer advertising (DTCA) and pharmaceutical promotion to physicians on the likelihood that (1) an individual diagnosed with depression received antidepressant medication and that (2) antidepressant medication was used for the appropriate duration.

A quasiexperimental design was used to examine treatment patterns of 30,621 depressed individuals whose insurance claims were included in the MarketScan database from 1997 through 2000. The main explanatory variables were spending on DTCA, detailing to physicians, and free samples for 6 antidepressant medications.

Individuals diagnosed with depression during periods when class-level antidepressant DTCA spending was highest (cumulative spending more than US 18.5 million dollars) had 32% higher relative odds of initiating medication therapy compared with those diagnosed during periods when DTCA spending was lowest (P < 0.0001). Free samples of medications dispensed to physicians had no effect on odds of initiating antidepressant use. Class-level DTCA spending on antidepressants had a small positive effect on the duration of antidepressant use, whereas DTCA spending for the specific medication taken by an individual had no effect on treatment duration. Detailing spending at the class or product level had no significant effect on duration of treatment with an antidepressant medication.

Our results suggest that DTCA of antidepressants was associated with an increase in the number of people diagnosed with depression who initiated medication therapy. DTCA was associated with a small increase in the number of individuals treated with antidepressants who received the appropriate duration of therapy. Promotion to physicians was not associated with either the initiation of treatment with an antidepressant or with the duration of therapy.