BROOMFIELD, COLO. — The steep rise in antidepressant prescribing over the last several decades and the temporally associated decline in suicide rates in many Western countries are not causally related, Annette Erlangsen, Ph.D., said at the annual conference of the American Association of Suicidology.
Her 5-year study of the entire older population of Denmark—with accompanying data on individual prescriptions filled for antidepressants—showed that the vast bulk of the drop in the Danish suicide rate during the follow-up period involved the 96% of Danes not on an antidepressant.
“These findings do not provide information on whether SSRIs [selective serotonin reuptake inhibitors] or other types of antidepressants prevent suicides on an individual level,” said Dr. Erlangsen of Pennsylvania State University, University Park.
“Nevertheless, our results show that the increased use of SSRIs has not had an impact on the change in the total suicide rate during the second part of life. SSRIs have not worked as a prevention strategy on a universal level,” she added.
She presented a 5-year follow-up covering the years 1996–2000 involving all of the nearly 2.5 million Danes aged 50 years or older. She also restricted her study, which was based upon Danish national health registry data, to older Danes because suicide rates are highest in seniors, who also consume proportionately the largest amount of SSRIs.
During the study period, 1,430 older Danish men and 710 older women committed suicide. The suicide rate fell from 35.4/100,000 among older men in 1996 to 27.1/100,000 in 2000. Similarly, the annual suicide rate among older women dropped from 14.4 to 11.3/100,000.
A key finding in this study was that 90% of the decline in the suicide rate among older men and 76% of the decline in women was accounted for by individuals not on antidepressant, she continued. The suicide rate in persons on an antidepressant was far higher than in those who weren't.
The rate did decline over time in antidepressant-treated patients, but only minimally—to a far lesser degree than in older Danes not on such therapy.
The suicide rate in individuals on tricyclic antidepressants proved similar to that in SSRI-treated patients. This was a surprising finding in light of the tricyclics' notorious lethality in overdose.
The suicide rate actually rose slightly over time among Danes on atypical antidepressants. The most likely explanation is that these newer medications were largely reserved for patients who'd already failed to respond to other antidepressant classes.