A Food and Drug Administration federal panel Wednesday recommended the agency issue its strongest possible warning to alert patients and doctors that antidepressants can increase the risk of suicidal thoughts and behavior in young adults.

The panel called for placing the so-called "black-box" warning on product labels and in medication guides distributed to patients.

Since 2004, antidepressants have had a black-box warning about an increased risk of suicidal thoughts and behavior in children and adolescents. The recommendation to extend that warning to patients in their late teens and 20s came after a review of 372 clinical trials. The review found that the risks were related to age, and that the dangers seemed to disappear at age 25.

Still, some panel members said 25 seemed like an arbitrary cutoff.

"I am concerned that there is a false sense of security to some of these age brackets," said panel member Dr. Marcia Slattery, a University of Wisconsin psychiatrist. She said all patients taking antidepressants should be monitored for suicidal thoughts and behavior.

In the end, the panel decided to let the FDA decide the age limit of the warning. Patients younger than 25 account for about 8 percent of antidepressant prescriptions.

The panel's 6-2 vote came amid concerns that the black-box warnings might discourage young adults who need help from using the drugs. Several panelists called for balancing the warning with a statement underscoring the necessity to treat depression.

After the vote, FDA officials said they intend to expand the black-box warning to include young adults.

The FDA's review, which looked at 100,000 patients, found a small but significant risk of suicidal thoughts and behavior among 18- to 24-year-olds who took antidepressants. The agency said four of 1,000 patients were at increased risk.

The FDA study found no increased risk in patients ages 25 to 30. The drugs seemed to protect against suicidal thoughts and behaviors after age 30 and particularly after age 65, the agency said.

The FDA had no explanation for the apparent age-related effects.

Half the patients studied took the drugs for depression; the rest were testing the medicines for psychological disorders such as anxiety, or for behavior modification, including smoking cessation and obesity.

Across all the studies, eight people committed suicide, 134 attempted suicide and 528 thought about killing themselves or prepared to do so. The FDA said actual suicides were too infrequent to draw any association to the drugs.

The research focused on selective serotonin reuptake inhibitors Celexa, Lexapro, Luvox, Paxil, Prozac and Zoloft; serotonin-norepinephrine reuptake inhibitors Cymbalta and Effexor; and other antidepressants Remeron, Serzone and Wellbutrin.

The panel's decision applies to all antidepressants.

The vote came after an emotional hearing in which family members pleaded for strong warnings on drugs that they believed had caused loved ones' suicides.

"We deserve to be told all the side effects," said Kim Witczak of Minneapolis, whose husband, Woody, 37, hanged himself in 2003 after being prescribed Zoloft for insomnia.

But members of medical associations argued against the black box, saying it could lead indirectly to an increase in suicides because doctors might be afraid to prescribe the drugs for people who need them.