For now the warning labels--first required in 2004--apply only to children and adolescents.
The new recommendations come in the wake of an FDA review, released last week, of more than 372 studies of 11 drugs, including Zoloft, Prozac, Paxil and Lexapro.
The review found that the drugs may increase the risk of suicidal thoughts and suicide attempts among adults younger than 25. The study found that 4 percent of 18- to 24-year-olds who took the drugs reported suicidal thoughts or suicide attempts, as opposed to 2 percent of patients who took a placebo.
A 2004 FDA review found similar results for children and adolescents, leading to the original warning labels.
The results for older adults were mixed, and the new FDA report concludes that antidepressants may reduce the risk of suicidal thoughts for 25- to 64-year-olds, and may reduce the risk of both suicidal thoughts and behavior for people older than 65.
Researchers don't know exactly why antidepressants may increase suicidal thoughts in young people. However, they do know that the "rollback phenomenon" may contribute to increased suicide attempts. The rollback phenomenon occurs because antidepressants tend to increase patients' energy levels before improving their moods.
"If you have a very depressed unhappy person and you start them on medicine, the first one or two weeks on therapy when they're feeling a little better is when they're at highest risk of wanting to kill themselves," child psychiatrist Adelaide Robb told the NewsHour in a 2004 interview.
"And the reason is they finally have enough energy to get out of bed and go to the store and buy the Tylenol or the razor blades. Not because the medicine makes them worse, but because the medicine makes them well enough to finally do it."
Despite the FDA findings, the warning labels have been controversial from their inception. Some psychiatrists and other health-care providers worry that the warnings--called "black-box" warnings because they appear on drug labels in bold type inside black boxes--may scare patients and doctors away from effective treatment.
"There is a danger when we paint a medicine as so scary or so potentially dangerous that people avoid it," Carolyn Robinowitz, incoming president of the American Psychiatric Association, told Reuters.
Psychiatrists who oppose the warning labels point to a Centers for Disease Control statistic that found that the suicide rate among teenagers rose slightly in 2004 for the first time in a decade, according to the New York Times. And a recent study from the Netherlands found that the suicide rate among children and adolescents there had increased by more than 40 percent since 2003, when antidepressant prescription rates in that country began to drop.
Many psychiatrists think those findings suggest that the benefits of antidepressants outweigh the risks.
"Untreated depression causes more loss of life than any of the approved treatments," Robinowitz told USA Today. "A black box for adults creates a fear mentality, not only in patients but in doctors...It can limit access to needed care."
Proponents and critics of the black-box warnings--including family members of people who had committed suicide while taking antidepressants--spoke before an advisory panel today. FDA officials said they would ask the advisory panel for input on the agency's plans to add information about adult suicide risk to the drug labels.