Antidepressant Dosages Complicate Suicide-Prevention Assessment

Maria Oquendo, M.D., an associate professor of clinical psychiatry at Columbia University, and colleagues launched a study to find the answer. They focused on the fates of 136 persons who had been hospitalized for major depression but who were treated naturalistically in their communities after that, either by primary care physicians or by psychiatrists.

Oquendo told Psychiatric News that the exact number of patients treated by each type of physician was not known but that “a substantial number—at least 50 percent—were probably seen by psychiatrists.”

Oquendo and her coworkers assessed the 136 subjects at three months, one year, and two years after hospital admission for the presence of major depression, the adequacy of antidepressant treatment for it, and any suicidal acts they had committed. The adequacy of antidepressant treatment was measured with the Antidepressant Treatment History Form. It is used to score the adequacy of treatment trials for major antidepressant medication categories on a scale of 0 to 5. A score of 3 or above is considered adequate treatment unless the patient responds to a lower dose. The investigators then attempted to see whether subjects receiving medication adequate for their depression were shielded from suicide.

The investigators, however, could not come up with an answer, they reported in the October American Journal of Psychiatry. So many of the subjects were receiving what was considered inadequate treatment for their depression that it was not possible to measure whether adequate treatment protected against suicide. Of those who were treated, the mean rating for treatment adequacy was 2.5, below the minimum for adequate treatment. In fact, 18 of the 136 subjects—13 percent—received no antidepressant medication during the study period.

Nonetheless, of the 21 subjects who made a suicide attempt during the two-year study, nine were getting what seemed to be adequate antidepressant medication for their needs. So it looks as though, even when depressed individuals are receiving antidepressant medications that appear to be sufficient to combat their depressions, they may still be physiologically treatment resistant and thus at suicide risk.

The next step in determining whether antidepressants can protect against suicide prompted by major depression, Oquendo and her colleagues explained in their study report, is not a naturalistic study like the one they just conducted, but one in which researchers measure the levels of antidepressants in subjects’ blood.

Oquendo, in fact, is already investigating whether medications can protect against suicide linked to bipolar disease, she told Psychiatric News. This investigation, she explained, is large, controlled, and prospective, and compares the efficacy of lithium and valproate in the prevention of suicidal behavior in patients with bipolar illness. “We will be following patients for two years and monitoring their clinical status and blood levels carefully,” she said.

The study was funded by grants from the National Institute of Mental Health.