Seniors are nearly five times more likely to commit suicide in the first month after they start taking antidepressants such as Prozac, Paxil or Zoloft, a Canadian study concludes.

But it also found that the overall risk of suicide among seniors taking antidepressants is low, and that the risk with new drugs is high for just the initial month of taking the medications.

SSRIs such as Prozac are a newer class of antidepressant.
SSRIs such as Prozac are a newer class of antidepressant.

Researchers compared seniors taking a newer class of antidepressants known as selective serotonin re-uptake inhibitors, or SSRIs with those taking older drugs for depression called tricyclics like Elavil.

Using Ontario coroners' reports, prescription records and data from hospitals, the team concluded the risk of suicide was higher among those 66 or older taking an SSRI, but only during the first month on the treatment.

"I think what people need to appreciate is that a very small segment of the population that takes these drugs may experience more suicidal thoughts or new suicidal thoughts, and they need to watch for that," said Dr. David Juurlink, one of the authors of the study at the Institute for Clinical Evaluative Sciences in Toronto.

Older people are at high risk of suicide and they are often taking SSRIs, but historically the population has been understudied, he said. Earlier studies concluded there's an increased prevalence of suicidal thoughts among children and teens taking SSRIs.

Unlike previous studies, Juurlink's team looked at suicides, rather than suicide attempts.

One suicide was committed for every 3,300 people that started an antidepressant, they report in the May issue of the American Journal of Psychiatry.

The study's authors caution that patients should not go off these drugs without first talking to their doctors. Those contemplating being treated for depression shouldn't be dissuaded from seeking treatment based on the results, they added.

"You know, we found that two-thirds of people that committed suicide were not on any type of antidepressant," said Jurrlink. "To me, [that] highlights the undertreatment of depression in seniors."

It's possible the drugs are both underprescribed for people with severe depression and overprescribed for those with very minor depression, he said. "We need to be a bit more judicious in how we use these drugs. They are a treatment for depression, not for feeling a little blue now and again."