A large Finnish study has found that suicidal individuals taking antidepressant medications appear to have an increased risk of additional suicide attempts, but a reduced risk of dying from suicide or any other cause.
A large risk factor for suicidal behavior is major depression. However, medications used to treat depression have also been linked to suicidal attempts and behavior, especially among children and adolescents taking a type of antidepressant known as selective serotonin reuptake inhibitors (SSRIs).
The issue is difficult to study because the number of completed suicides is relatively low; an effective study would have to include tens of thousands of patients and last for several years. Finnish epidemiological studies are typically viewed as robust given national registries and databases of all residents and incidents of care.
“Because previous suicide attempts are the most important risk factor for predicting suicide, a large cohort of suicidal patients would be an obvious choice to investigate the association between antidepressant treatment and the risk of suicide,” the authors write.
The study is reported in the December JAMA issue of Archives of General Psychiatry.
Jari Tiihonen, M.D., Ph.D., University of Kuopio and Niuvanniemi Hospital, Kuopio, Finland, and colleagues analyzed data from all individuals hospitalized in Finland for suicide attempts between 1997 and 2003. Information about 15,390 hospitalized individuals—including age, sex, location, dates of admission and discharge, number of previous hospitalizations for attempted suicide and antidepressant prescriptions—was gathered through Finnish national registries and databases. The patients were followed for an average of 3.4 years to see if they attempted suicide again, completed suicide or died from another cause.
Among the 7,466 males and 7,924 females in the study, 602 suicides, 7,136 suicide attempts leading to hospitalization and 1,583 deaths were recorded during follow-up. The risk of completed suicide was 9 percent lower among those taking any antidepressants than among those not taking antidepressants. However, the association varied by antidepressant—individuals taking an SSRI known as fluoxetine had a 48 percent lower risk of suicide (6.7 deaths per 1,000 total years that individuals took the drug) compared with those not taking medication (11 deaths per 1,000 years), while those taking venlafaxine hydrochloride, another SSRI, had a 61 percent increased risk (22.5 suicide deaths per 1,000 total years of medication use). The risk of death from any cause was 31 percent to 41 percent lower among those taking antidepressants.
Those taking SSRIs had a 61 percent reduced risk of death compared with those taking no antidepressants, a fact that could be attributed to a reduction in deaths related to cardiovascular disease and stroke.
Patients taking any kind of antidepressant had a 36 percent increased risk of a subsequent suicide attempt leading to hospitalization (204.7 per 1,000 total years of taking medications) compared with those taking no antidepressants (106.2 per 1,000 years); a slightly greater increase in risk was observed among those age 10 to 19 years (132.7 per 1,000 years for those taking antidepressants vs. 82.9 for those not taking antidepressants).
Among those who had ever taken antidepressants, current antidepressant use was associated with a 39 percent increase in risk of attempted suicide but a 32 percent decrease in risk of completed suicide and a 49 percent reduced risk of death from any cause.
“This opposite type of effect on fatal vs. nonfatal suicidal behavior may be explained by an increased risk of intoxication because of easy availability of means (antidepressant medication), resulting in an increase in nonfatal suicidal behavior, and by a decrease in the incidence of violent and more fatal methods of suicide attempts, such as hanging and shooting,” the authors write.
The article may be found in the Archives of General Psychiatry, 2006;63:1358-1367