The scientists compared the patient information to hospital discharge records and death registers from 1980 to 2000. According to the records, 128 of the people surveyed were admitted to a hospital after a suicide attempt.

“Severe acne is not a trivial condition,” wrote Anders Sundstrom and colleagues. “It is associated with an increased risk of attempted suicide.” Experts found the number of suicide attempts increased between about one and three years after the start of the treatment. But the highest risk appeared to be within six months after the treatment ended. Treatment typically lasted several months, with some patients needing repeated therapy, the report said.

The scientists could not say whether it was the condition or the treatment that is causing the suicide attempts among those using the drug. They even suspect that patients whose acne improved after treatment might still be upset if there were no major improvements in their social lives.

Sundstrom and colleagues emphasized that acne-related suicide attempts was a rare event: there was about one suicide attempt for every 2,300 people taking the acne drug. Among young adults in the US, there are about 13 suicides per every 100,000 people. Experts estimate that for every suicide, there are about 11 attempts.

“All patients with acne of a severity for which isotretinoin is (needed) should have psychosocial factors and suicidal intent monitored,” wrote Parker Magin and John Sullivan of the University of Newcastle and University of New South Wales in Australia, in an accompanying commentary. “Given the extended period of risk, families of patients may also have a role in this monitoring.” The study was paid for by the Swedish Research Council and was published Friday in the medical journal BMJ.