Gregory Simon obtained a research grant from Lilly and consulting fees from Pfizer and Philip Wang, another researcher, was on the paediatric Food and Drug Administration's advisory committee that recommended that a so-called black box warning on suicide risk be placed on the labels of antidepressants.
The study, published in the American Journal of Psychiatry, reviewed records for 65,103 Group Health Cooperative members in Washington and Idaho.
The link between antidepressants and suicidal thoughts and self-destructive behaviour has been under discussion since March 2004 when the Food and Drug Administration warned doctors they should closely monitor patients on 10 drugs. In October 2004, the FDA also warned about use of the medicines for children and teenagers.
The risk of suicide attempts appeared to be greatest in the month before patients were first treated, according to the study. There was a smaller, significant increase in those attempts in the week after patients received antidepressants, and then a decline over the subsequent period, researchers said.
The drugs include in the original FDA warning were Effexor, Prozac, Pfizer Inc.'s Zoloft, GlaxoSmithKline Plc's Paxil, Solvay SA's Luvox, Biovail Corp.'s Wellbutrin, Forest Laboratories Inc.'s Celexa and Lexapro, Bristol-Myers Squibb Co.'s Serzone and Akzo Nobel NV's Remeron. Many of these drugs, such as Prozac, are now available in generic form.
Paul Seligman, director of the FDA Office of Pharmacoepidemiology and Statistical Sciences, said the agency is concerned about drug warnings discouraging the use of these products.
The researchers admitted there is still a possibility that antidepressants may prompt suicidal thoughts or attempts in a group of more vulnerable people. Teenagers, for example, were only a small portion of the study, with three suicides and 17 serious attempts, the researchers said.
Wayne Goodman, who was chairman of the FDA panel that reviewed the link between antidepressants and suicidal thoughts and behaviour in children and teenagers, claimed that the drugs work in adults but that young people might be more sensitive.
