The use of antidepressants in the USA doubled between 1996 and 2005, notes a new report, though rates remain low among ethnic minorities.

The study, published in the August issue of Archives of General Psychiatry and sponsored by the Agency for Healthcare Research and Quality, noted that 18,993 people aged six and older were included in the 1996 survey and 28,445 in the 2005 poll. Between 1996 and 2005, the rate of antidepressant treatment increased from 5.84% to 10.12% or from 13.3 million to 27 million individuals.

The authors, Mark Olfson of the New York State Psychiatric Institute, and Steven Marcus of the University of Pennsylvania, Philadelphia, said that “significant increases in antidepressant use were evident across all sociodemographic groups examined, except African Americans, who had comparatively low rates of use in both years (1996, 3.61%; 2005, 4.51%)". They added that although antidepressant treatment increased for Hispanics, it remained comparatively low (1996, 3.72%; 2005, 5.21%).

Among antidepressant users, the percentage who were also prescribed antipsychotic medications increased between 1996 and 2005 (5.46% vs 8.86%), but fewer also underwent psychotherapy (31.5% vs 19.87%). The authors write that together with an increase in the number of antidepressant prescriptions per user (an average of 5.6 vs 6.93 per year), “these broad trends suggest that antidepressant treatment is occurring within a clinical context that places greater emphasis on pharmacologic rather than psychologic dimensions of care”.

Interestingly, the report states that "although there was little change in total promotional spending for antidepressants between 1999 ($0.98 billion) and 2005 ($1.02 billion), there was a marked increase in the percentage of this spending that was devoted to direct-to-consumer advertising”, from 3.3% ($32 million) to 12 ($122 million).

The report concludes that several factors may have contributed to the overall increase in prescriptions – major depression may have become more common (and more socially acceptable) and several new antidepressants were approved by the US Food and Drug Administration to treat depression and anxiety disorders during the study period. In addition, clinical guidelines have been published that support the use of these medications for a variety of conditions.