The U.S. Food and Drug Administration (FDA) ordered drug makers yesterday to add new warnings to all antidepressant medications, saying the drugs increase the risk of suicidal thinking or behavior in some young adults up to age 25.

The FDA ordered the makers of 36 antidepressant drugs, such as Zoloft, Prozac and Paxil, to add the precautionary warnings to the prescription information. The expanded warnings will appear in a black box displayed prominently on the prescribing information. Antidepressant drug labels have included similar warnings for adolescents and children since 2005. The so-called “black box label” is the strongest caution that FDA regulators can impose.

This past December, an FDA expert advisory panel advised of the new warnings after an investigation into antidepressant drugs that found that in most instances, depression and other mental health issues are responsible for the majority of suicide attempts, not the use of antidepressants. The labeling changes follow the recommendations of the advisory panel, which included psychiatrists and consumer representatives. That panel heard scientists as well as dozens of other people who told of loved ones who had committed suicide after having been prescribed antidepressants.

The drug agency reached its conclusions after analyzing nearly 300 studies of antidepressants, which in total included over 75,000 adult research subjects. The analysis found no increased risk of completed suicides in people taking antidepressant medications.

However, among 19- to 24-year-olds taking the antidepressants, 21 people did attempt suicide. This resulted in the panel concluding that antidepressants presented twice the risk in young adults of the same age who took placebo pills.

The panel also found that antidepressants appear to reduce the risk of suicide in adults older than 64.

The FDA reminded people who currently taking antidepressants that they should not stop taking them based upon this new warning, but instead consult their doctors if they have any concerns.