A widely publicized warning by U.S. regulators a decade ago about risks for teens taking antidepressants led to plummeting prescriptions and increased suicide attempts, Harvard University researchers said.

As the public took the Food and Drug Administration's (FDA) 2004 warning to heart, adolescent attempted suicides increased 21.7 percent and a 31 percent decline in antidepressant use was seen two years later, according to research published last week in BMJ, formerly the British Medical Journal. Attempted suicides among those aged 18 to 29 increased 33.7 percent.

The effect of a regulatory warning that gained wide attention in the media shows the need for better communication by public health professionals, said Christine Lu, the study's lead author. The drop in antidepressant prescriptions among adolescents and young adults probably means depression went untreated, she said.