Suicidal behavior among adults taking antidepressants drops almost as soon as they begin medication, researchers said on Sunday in findings that experts said confirm their effectiveness in older patients.

The decline was especially significant among patients taking newer drugs to treat depression, including selective serotonin reuptake inhibitors, or SSRIs, compared to those taking older medicines.

The findings, published in the January issue of the American Journal of Psychiatry, come as experts grapple with whether such drugs can provoke suicidal tendencies.

In 2004, the Food and Drug Administration concluded there was a higher risk of suicidal behavior among children and teenagers and ordered strong label warnings. In July, it said there may be a link in adults and urged close monitoring.

However, after reviewing more than 65,000 patient records from 1992 to 2003, researchers in Seattle found fewer suicide attempts or deaths after patients began medication.

In the six months after medication, there were 76 attempts severe enough to require a hospital visit compared with 73 attempts in the three months prior.

Adolescents showed more attempts than adults, but there was not enough data for a strong conclusion. About 6 percent of patients were 17 and younger, according to the study funded by the National Institute of Mental Health (NIMH).

Researchers reviewed records from the Group Health Cooperative health plan.

“The conventional wisdom that the first few weeks of treatment are especially risky doesn’t seem to be true,” said psychiatrist Gregory Simon, a researcher for the cooperative.

AT ODDS WITH THE FDA

His conclusion differs from the FDA’s, he said, because his team reviewed behavior in the time before treatment rather than once medication began, as in placebo-controlled trials.

Others questioned such a broad statement, saying the records included patients with previous suicidal behavior who could skew results. They also did not count thoughts or other symptoms not requiring hospitalization.

“If you’ve selected for people who’ve had a suicide attempt ... it’s not surprising the suicide rate goes down with treatment,” said University of Florida psychiatrist Wayne Goodman, an FDA advisor. “I think you have to be careful what conclusion you draw.”

Goodman and others said the findings confirm antidepressants help adults. They also welcomed the strikingly higher improvement among patients taking newer medications, such as Eli Lilly & Co’s Prozac.

Other antidepressants include GlaxoSmithKline Plc’s Paxil, Pfizer Inc’s Zoloft and Forest Laboratories Inc.‘s Celexa, among others.

To be sure, Simon said, suicide risk still exists and patients should be monitored closely.

FDA spokeswoman Susan Cruzan said the analysis would not affect current warnings, which offered “good information.” She added the FDA was continuing its review for adults.

SOURCE: American Journal of Psychiatry, January, 2006.