Researchers estimate that after the availability of the new generation of drugs for depressiondepression, there were 33,600 fewer suicide deaths than would have otherwise been expected between 1988 and 2002. They use mathematical probability modeling to come up with the figure.
Researcher Julio Licinio, MD, who led the study while at UCLA, is now chairman of the department of psychiatry and behavioral science at the University of Miami's Leonard M. Miller School of Medicine.
"The overall message is that on a population level these drugs are safe," he tells WebMD. "They have been prescribed in huge numbers and suicides have been going down."
The study joins a growing body of research challenging claims that the widely-prescribed selective serotonin reuptake inhibitor (SSRI) antidepressants are linked to an increased risk of suicidal thoughts and behaviors.
Researchers analyzed suicide data from the CDC and the U.S. Census Bureau from the early 1960s until 2002. They looked at deaths from suicides and did not include suicidal behaviors or suicidal feelings or thoughts in their analysis.
They found that while suicide rates remained fairly steady for the 15 years prior to introduction of Prozac (fluoxetine) in 1988, they dropped steadily over the next 14 years as sales of the drug increased.
Prozac was the first SSRI antidepressant to be sold in the U.S. and it is still the most widely prescribed antidepressant. Sales of Prozac skyrocketed from 2.5 million prescriptions in 1988 to around 33 million in 2002.
The study reports that between 12.7 and 13.7 suicides occurred among every 100,000 people in the U.S. from the early 1960s until 1988. Suicides steadily declined after that to a low of 10.4 per 100,000 in 2000.
Licinio and colleagues developed a mathematical model designed to estimate the impact of SSRI use on suicides. Based on suicide figures prior to the introduction of the antidepressants, the researchers concluded that there was a cumulative decrease in expected suicides of 33,600 from 1988 through 2002.
Early Monitoring Important
While the findings suggest SSRI use has resulted in a decrease in suicides among the population at large, they say nothing about whether the drugs pose a risk for specific subpopulations of users.
Seattle-based psychiatrist Gregory E. Simon, MD, MPH, tells WebMD that it would take much larger studies than are likely to be performed to answer that question. Simon is a researcher for Group Health Cooperative, a nonprofit private insurer in the Pacific Northwest.
Other studies have suggested that if there is an increase in suicide risk associated with SSRI use, it is greatest in the early days and weeks of treatment. For that reason, the FDA has called for close monitoring of newly-treated patients.
Simon agrees that close monitoring is important -- but not because the antidepressants are dangerous. Rather, it is important, he says, because finding an antidepressant that works often takes time.
"Unfortunately, many people who start taking these drugs stop within a week or so because they don't seem to be working," Simon says.
Careful early monitoring could boost the effectiveness of antidepressant treatments from 40% to 50% up to around 75%, he says.
Closer monitoring of patients when they start SSRIs is a positive outcome of the suicide-risk controversy, Licinio says.
"It used to be that people were put on these drugs and told to come back in a few months, but that is not happening so much anymore," Licinio says. "These drugs do change mood and behavior among very vulnerable people, so close monitoring is important."