MONDAY, June 12, 2006 (HealthDay News) -- Countering recent reports that they might boost suicide risk in users, a major new study finds that antidepressants known as selective serotonin reuptake inhibitors (SSRIs) have actually saved thousands of lives by preventing suicides since they were introduced in 1988.
The benefits of SSRIs were particularly pronounced among females, said the authors of an independent study appearing in the June issue of the journal PLoS Medicine.
"As the number of [SSRI] prescriptions go up, the number of suicides are going down," said Dr. Julio Licinio, chairman of the department of psychiatry and behavioral sciences at the University of Miami Miller School of Medicine. "I don't see how these drugs could be causing suicide if the rates [of suicide] are actually going down."
Licinio was lead author of the study, which was conducted while he was at the University of California, Los Angeles.
The findings seemed to dovetail with other psychiatric workers' clinical experience.
"I've seen the SSRIs help people tremendously," said Helen Stavros, a clinical social worker in the department of psychiatry at Ochsner Health System in New Orleans. "I've never seen anyone become suicidal as a result of being on antidepressants." Stavros started working at Ochsner in 1987, shortly before the first-ever SSRI, Prozac, was approved.
Another expert called the finding interesting, but added a caution.
"The results of this study are consistent with previous reports. Fortunately, suicide rates have been declining since the early 1990's. While this correlates with the increased use of SSRI antidepressants, including fluoxetine, this finding does not, by itself, demonstrate a causal relationship," said Dr. David Fassler, a clinical professor of psychiatry at the University of Vermont College of Medicine in Burlington.
He added, "There are numerous other intervening variables, including socioeconomic factors, access to drugs, alcohol and firearms, and improvements in emergency medical care."
The past few years have witnessed a prolonged debate about the safety of antidepressant use, especially in children and teens.
In October 2004, the U.S. Food and Drug Administration directed manufacturers of SSRIs to revise their labeling to include a "black box" warning that alerts health-care providers to an increased risk of suicidality in children and teens.
In July 2005, the FDA issued a public health advisory that raised the possibility that the risk of suicidality also applied to adults taking SSRIs, after several studies pointed to that possibility.
Meanwhile, the European Medicines Agency (EMEA) ruled Thursday that children as young as eight can be given Prozac.
The group said that the drug was safe for young people to take, despite concerns that it can trigger suicidal feelings in patients. The ruling added that Prozac should only be given to children with moderate to severe depression who have not responded to several sessions of psychological therapy. It also said the drug should only be given in small doses and must be used alongside counseling.
British health authorities have also declared that all antidepressants except Prozac should not be used by children or adolescents.
Major depressive disorder, for which SSRIs are often diagnosed, afflicts about 10 percent of American men and 20 percent of American women during their lifetimes. At any one point in time, 3 percent of the population has the disorder (10 percent of the elderly).
For this study, the authors analyzed federal data on suicide rates since 1960, along with sales of fluoxetine (Prozac) since it became available in 1988. Analysis was continued through 2002.
"We used Prozac as a benchmark for the class of drugs," Licinio explained.
Between the early 1960s and 1988, suicide rates held relatively steady, fluctuating between 12.2 per 100,000 and 13.7 per 100,000.
Since 1988, however, suicide rates have been on a gradual decline, with the lowest point being 10.4 per 100,000 in 2000. During the same time frame, Prozac prescriptions rose, from 2,469,000 in 1988 to 33,320,000 in 2002.
Using mathematical modeling, the investigators estimated the rates of suicide if the pre-1988 trends had continued.
"On average, we estimated that there would have been an additional 33,600 suicides if the pre-1988 trends had been maintained," Licinio said. "We think that this [SSRIs] has had a substantial impact on the number of suicides."
With that in mind, moves to restrict the use of SSRI antidepressants could have a harmful effect, the authors stated.
"I don't think these claims that antidepressants increase suicide have a solid base," Licinio said. "If you have a drug that's supposed to be causing something, the more of the drug that's used, the more of the bad outcome you would have. What we show is the converse."
One troubling trend noted by the authors of the article is that the number of antidepressant prescriptions seem to be declining as a result of the recent controversy. That bothered other experts as well. "I see a lot of people being afraid of taking drugs when they could be really helpful to them," Stavros said.
Licinio is now planning a study to observe the effect of anti-depressants on suicidal thoughts and behaviors, because much of the available data comes from studies whose primary objective was something other than suicidality.
"Nobody, to my knowledge, has done this," he said. "Usually in science, the best idea is to test the point and not treat it as a by-the-way. Suicidality has [up until now] been assessed as a secondary factor."
Fassler agreed that more study is needed. "The finding is interesting, and somewhat reassuring, given the frequency with which these medications are currently used," he said. "Clearly, this is an area where additional research is warranted."
According to the authors, Eli Lilly -- the maker of Prozac -- was unaware of and not involved in the study, which was funded by a grant from the U.S. National Institutes of Health and the Dana Foundation. Licinio did, however, accept an offer to consult for Lilly after this research was accepted for publication.
For more on depression, head to the U.S. National Alliance on Mental Illness.