CHICAGO (AP) _ A study of nearly 2,800 British adults and children bolsters the evidence that patients are prone to suicidal impulses when they are first put on antidepressants. But it found no difference in risk between newer and older drugs.
The study looked at four drugs and found that suicidal thoughts or attempts were four times more likely during the first 10 days of treatment than they were after three months. Suicide was almost 40 times more common early on than later in treatment, though there were only 17 suicides, all in patients older than 19.
But the study is unlikely to resolve the debate over whether the drugs themselves increase the suicide risk.
And it may not soothe skeptics who maintain that newer drugs such as Paxil and Prozac that increase brain activity of the mood-regulating chemical serotonin are particularly risky for children. The study found no clear-cut evidence to support that idea, and the researchers did not specifically compare children on antidepressants with those not taking medication.
Some doctors argue that patients just starting on antidepressants are usually in the deepest throes of depression _ which itself can cause suicidal behavior _ and that the risks subside as the drugs take hold. Others say a medication-induced mood boost may give a profoundly depressed person just enough energy to act on suicidal thoughts.
But some relatives of people who have committed suicide blame the drugs themselves, and British health authorities have said that most serotonin-affecting antidepressants are unsuitable for children. GlaxoSmithKline, the maker of Paxil, has been hit with a lawsuit accusing it of suppressing studies indicating the drug might increase suicidal tendencies in children.
The U.S. Food and Drug Administration is investigating and earlier this year issued a public health advisory asking makers of 10 drugs to add or strengthen suicide-related warnings on their labels. Doctors were warned to watch patients on antidepressants carefully, especially when they first start taking the drugs.
The FDA advisory includes Paxil and Prozac but not the two other drugs studied _ amitriptyline and dothiepin, older medications that work differently. The newer drugs have gained favor in part because they have fewer side effects.
The study, by Drs. Herschel and Susan Jick and James Kaye at Boston University, appears in Wednesday's Journal of the American Medical Association. It was funded by the Boston Collaborative Drug Surveillance Program, which received consultation fees from Glaxo in connection with other research. The authors said Glaxo had no role in the current study's design.
The data ``simply means that antidepressants are being prescribed for the right indication, and that they do not immediately eliminate suicide risk,'' Drs. Simon Wessely and Robert Kerwin of London's Institute of Psychiatry said in a JAMA editorial. Still, careful monitoring of youngsters is essential, they said. Wessely has received funding from pharmaceutical companies including Prozac maker Eli Lilly and Co.
The researchers looked at 2,791 first-time users ages 10 to 69 of any of the four drugs from 1993 to 1999.
Suicidal tendencies were 29 percent more common among Paxil users than among dothiepin users studied. Kaye said that finding was statistically insignificant and could reflect doctors' tendency to prescribe the newest drug for more serious cases. Still, he said it ``doesn't exclude the possibility'' that Paxil is more risky.
Dr. David Fassler, a Vermont psychiatrist not involved in the research, said the study leaves key questions unresolved: ``This study isn't specific to children and adolescents, and that's been the area of most recent concern.''