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Study also highlights some concerns in reporting mechanisms.

Ottawa, February 17, 2005 - Basing their conclusions on an exhaustive review of published randomized controlled trials of selective serotonin reuptake inhibitors (SSRIs), a group of investigators led by Dr. Dean Fergusson, a scientist at the Ottawa Hospital Research Institute (OHRI) and an associate professor at the University of Ottawa, has found that anti-depressants contribute to a two-fold increase in the risk of suicide attempts.


Intrigued by a lengthy and well publicized debate questioning a link between anti-depressants and risk of suicide, Dr. Fergusson quickly realized that, given his extensive background in epidemiologic and analytic research, he could likely contribute to the answer. The study never questioned the value of these medications, but his findings, published in the most recent edition of the BMJ, inspire some concern and strongly encourage a closer monitoring of individuals who take these widely prescribed drugs.

The research included a review of studies of all SSRIs - a class of anti-depressant drugs which are widely prescribed and have been used to treat an ever-expanding list of clinical conditions. The research team reviewed randomized controlled trials comparing an SSRI with either placebo or an active, non-SSRI control. The study excluded abstracts, crossover trials, and all trials whose follow-up was less than one week. As a result, 702 trials were included in the study (representing 87, 650 patients with a wide range of clinical conditions) looking at both fatal and non-fatal suicide attempts. The overall rate of suicide attempts was 3.9 (95% confidence interval 3.3 to 4.6) per 1000 patients treated in clinical trials. When they used study duration as exposure time, Dr. Fergusson and his team found an incidence of 18.2 suicide attempts per 1000 patient. For the trials conducted in patients diagnosed with depression, the overall rate of suicide attempts was 4.9 (95% confidence interval 4.2 to 5.6 per 1000 patients).

Overall, the study noted a significant increase (more than twofold) in the odds of suicide attempts for patients receiving SSRIs compared with placebo or therapeutic interventions other than tricyclic antidepressants - another class of drugs. When compared to tricyclics, no increase in risk was found. Although it might appear small, the incremental risk remains a very important population issue because of the widespread use of SSRIs. While other studies have suggested a possible link, this review is now the most elaborate and comprehensive research identifying a very real correlation.

Dr. Fergusson's study also observed several major methodological limitations in the published trials and he adds that stronger and better reporting mechanisms might be in order.

It is still important to note, however, that these medications have very important benefits that should not be discounted. Anyone taking these drugs, who may have concerns, should first consult a physician or pharmacist.

"This study is important for two reasons," noted Dr. Fergusson. "First, it provides the most comprehensive and conservative evidence to date on the association between SSRIs and suicide risk. Second, it highlights deficiencies in trial design and the reporting of rare but serious harms."

"Dr. Fergusson and colleagues' study is timely and highly significant in that it raises concern about the relationship between uncommon but very important adverse events of attempted suicide and commonly prescribed antidepressant medications," said Dr. Robert Swenson, Deputy Head of Psychiatry at The Ottawa Hospital, Associate Professor of Psychiatry at the University of Ottawa and a Clinician Investigator at the Ottawa Hospital Research Institute. Dr. Swenson was also quick to remind us of the importance of these medications. "If antidepressant medication is helpful for their condition, people should not stop it. If they have concerns about their medication or their condition is worsening, they should talk to their doctor or pharmacist right away."

"This important study has highlighted the increased risk of suicide attempts in patients treated with SSRIs across a wide range of clinical indications," said Dr. Jeremy Grimshaw, Director of the Clinical Epidemiology Program at the OHRI. "It provides important information that will allow physicians and patients to make more informed decisions about the benefits and risks of SSRIs."

Also involved in the research were: Steve Doucette (research associate OHRI), Kathleen Cranley Glass (associate professor, McGill University), Stan Shapiro (professor, McGill University), David Healey (professor, University of Wales College of Medcine), Paul Hebert (senior scientist, OHRI), Brian Hutton (research associate, OHRI).

The Ottawa Hospital Research Institute is the research arm of The Ottawa Hospital and a major partner of the University of Ottawa Faculties of Medicine and Health Sciences.

The study was funded in part by the Canadian Institutes of Health Research.

For more information, please contact:

Nathalie Trepanier
Communications Manager
(613) 798-5555 ext. 19691
Fax: (613) 761-4920

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