Suicide Risk from Antidepressants Remains Unclear

Three new studies come to conflicting conclusions about risks for suicidal behavior associated with antidepressants such as Paxil, Prozac and Zoloft.

These and other selective serotonin reuptake inhibitor (SSRI ) medications have come under close scrutiny over the past year as isolated reports surfaced of adolescent users either killing themselves or attempting suicide while on the drugs.

However, these three new studies are not likely to clear up the confusion on this issue.

Together they "send a variable signal about increased suicidal behavior," said Dr. John Geddes, a professor of epidemiological psychiatry at the University of Oxford in England and co-author of an editorial accompanying the reports in the Feb. 19 issue of the British Medical Journal.

There is a "small but real risk" associated with their use, Geddes believes, and "the balance between benefits and risk probably is less favorable in the younger age group." However, SSRIs should not be ruled out automatically, but rather the balance should be weighed case by case, he said.

The possibility that antidepressant drugs, particularly SSRIs, increase the risk of suicide in younger people has become a hotly debated issue.

Last year, British authorities declared children and adolescents should be given no antidepressants other than Prozac. In October, the U.S. Food and Drug Administration told drug companies to put a "black box" warning label on the medications, cautioning doctors and consumers of the potential risk for suicidal thoughts or behavior in pediatric patients.

The three new studies approach the issue from different angles. The largest, conducted at the Medicines and Healthcare Products Regulatory Agency in London, looked at data on more than 146,000 people taking either SSRIs or older tricyclic antidepressants in the United Kingdom.

That study found "no evidence that the risk of suicide or non-fatal self-harm in adults prescribed SSRIs was greater than in those prescribed tricyclic antidepressants," its authors wrote. But they did note "some weak evidence" of such behavior in SSRI users aged 18 or younger.

A second study looked at data on more than 40,000 people taking part in 477 controlled trials. "We found no evidence that SSRIs increased the risk of suicide, but important protective or hazardous effects cannot be excluded," wrote the researchers, from the University of Bristol in England, who did the study. They, too, said they detected "weak" evidence of an increased risk of self-harm.

"Larger trials with longer follow-up are required to assess the balance of risks and benefits fully," they concluded.

The third study, amassed data on close to 88,000 participants enrolled in 702 clinical trials. It found a "significant increase in the odds of suicide attempts," which were found to be twice as likely in people taking SSRIs than in those taking a placebo.