Dec. 7, 2000 -- While people who are being treated for depression are more likely to take their own lives than are the rest of the population, their rate of suicide is actually much lower than researchers have believed for the past 30 years, conclude the authors of a new study.
The researchers, from the Mayo Clinic in Rochester, Minn., also found that the risk of suicide is highest for people who have been hospitalized, and lowest for those treated in an outpatient setting, such as in a therapist's office. They also stress that while suicide is a rare event, most people who commit suicide have never received any mental health care.
Historically, psychiatrists and other mental health professionals have followed the findings of a 1970 study, which calculated that depressed people had a 15% chance of dying as a result of suicide during their lifetimes. Although this initial study referred only to people who had been hospitalized, the statistic was widely reported and eventually came to be applied to all people with depression. Another study published in 1990 drew the same conclusion.
But this rate seemed too high to John Michael Bostwick, MD, a consulting psychiatrist at the Mayo Clinic, so he decided to investigate further. Bostwick reviewed studies that reported suicide rates among people with depression, including both the 1970 and 1990 studies. He concluded that the method used to arrive at the 15% was incorrect, and applied a different strategy.
Bostwick also decided that the rate was inaccurate these days because the diagnosis of depression is applied far more broadly than it once was, and now includes people who are less severely ill.
Bostwick also tried to determine what would make the suicide rate higher or lower for patients with depression. What he found was an 8.6% chance of suicide among depressed persons who had been hospitalized after a suicide attempt or for suicidal thoughts; a 4% chance that depressed persons who had been hospitalized -- but not for suicidal behaviors -- would kill themselves; and only a 2% chance that someone with depression being treated as an outpatient would commit suicide at some point in their lives. The rate of suicide in the entire population is 1%.
"Any suicide is one too many, but that does not mean we can't get more realistic about who is at risk," Bostwick tells WebMD. "We don't want to minimize any of this, but we are also selling medications based on these statistics. And there is a lot to suggest that we need to put our efforts toward the two-thirds of people who kill themselves who have never had any contact with mental health professionals."
Adds Bostwick: "the point is ... we can go around and around on this, but the number is incorrect, it is too broad and it is misquoted." He says it is time to change the numbers in the textbooks, and several depression experts who spoke to WebMD agree.
Donald W. Black, MD, professor of psychiatry at the University of Iowa School of Medicine, is an author of one of the textbooks that has quoted the 15% figure. After reading the paper, Black reviewed a passage himself and determined that he would need to make a correction to the text, which is in revision now.
When asked if his care of patients would change based on a lower number, Black replied, "absolutely not." He says he agrees with Bostwick that no matter what the suicide rate is, an accurate and thorough examination to determine someone's chance of committing suicide is an essential part of treatment.
"Depressed patients still have a much higher risk for suicide and suicidal behavior than the general population," says Black. "The greatest task of all psychiatrists is to ensure the safety of their patients. It doesn't reassure me. Every psychiatrist I know has had patients who killed themselves and we know personally what a tragedy it is."
"The main point is that the risk of suicide with depression is real, substantial, and higher than a nondepressed sample but not as high as previously reported because of the populations studied," says Andrew A. Nierenberg, MD, associate director of the Depression Clinical and Research Program at Massachusetts General Hospital, and an associate professor at Harvard Medical School, both in Boston.
But even though the rates are lower than previously believed, he emphasizes that we should never lose sight of the fact that "depression can be fatal."