Antidepressant use tied to suicide attempts.

PARIS -- A cohort study of 15,390 suicide-prone people in Finland found those who used antidepressants were much more likely to attempt suicide, but also much less likely to complete suicide or to die of any cause.

The use of antidepressants was associated with a 39% increase in suicide attempts, a 32% reduction in completed suicides, and a 49% drop in mortality, Dr. Jari Tiihonen reported at the annual congress of the European College of Neuropsy-chopharmacology.

Dr. Tiihonen, professor and chair of the department of forensic psychiatry at the University of Kuopio in Finland, said the results for patients aged 10-19 corresponded to those for the total study population with one exception. Adolescents were more than five times more likely to die while on paroxetine (relative risk 5.44).

By phrasing the central question addressed by the study as, "Is antidepressant use associated with increased risk of suicidal behavior?" he said in conclusion that the answer is, "Yes, because of the increased risk of attempted suicide ... but at the same time, no, because there is a decreased risk of completed suicide, and this is also very large."

Dr. Tiihonen and his colleagues took advantage of Finland's nationwide computerized database of medical records to conduct the study. The investigators collected data on 15,390 people in a national hospital register who had been hospitalized during 1997-2003 because of suicide attempts. They also gathered data on these patients from a national prescription register and a national mortality register. The average follow-up period was 3.4 years.

"Since prior suicide attempts are the most important risk factor for suicide, a large cohort of suicidal patients would be an obvious choice to investigate the association between antidepressant treatment and the risk of suicide," Dr. Tiihonen said.

The study recorded 602 suicides, 7,136 suicide attempts, and 1,583 deaths in the cohort. "The more prior suicide attempts, the more the risk of suicide goes up as well as the attempts," Dr. Tiihonen said of the population, which ranged from 10 to 100 years of age.

Among patients who attempted suicide during this time, the investigators determined that 3,224 took antidepressants and 3,912 did not. All classes of antidepressants were associated with increased risk of attempted suicide (adjusted relative risk 1.64), compared with no antidepressant use, he reported.

Completed suicides were significantly less common overall (adjusted relative risk 0.81) in those taking antidepressants, but the risk varied according to the specific antidepressant used. Patients on fluoxetine had the lowest adjusted relative risk (0.52) of suicide while those on venlafaxine had the highest (1.61).

"Venlafaxine is generally considered to be one of the most efficacious, and it is used for patients who are the most severely depressed and the most severely suicidal," Dr. Tiihonen said.

He attributed the significantly reduced risk of all-cause mortality to the impact of SSRIs. Patients on SSRIs had significantly lower mortality (relative risk 0.59), a benefit the investigators credited to significantly fewer cardiovascular and cerebrovascular deaths in this subgroup (relative risk 0.42).

In response to audience questions, Dr. Tiihonen said an analysis not presented at the meeting found that patients were at greatest risk of suicide immediately after starting their medications.

He also suggested that the disparity between attempted and completed suicides might occur because patients on antidepressants are more likely to overdose on pills, simply because they are available. According to Dr. Tiihonen, those not on antidepressants tended to use more violent methods, such as shooting or hanging themselves.

"Antidepressant use is not associated with increased risk of suicide," he said.

BY JANE SALODOF MACNEIL

Southwest Bureau