Patients aged 70 and older who continued to take the antidepressant that initially helped them to recover from their first depressive episode were 60 percent less likely to experience a new depressive episode than those who stopped taking the medication, according to a study published in the New England Journal of Medicine. The study, which was funded by the National Institutes of Mental Health, showed that continuing this initial medication for a two-year period after a patient was symptom-free was effective in preventing the recurrence of depression.

"Most geriatric psychiatrists would not have thought that elderly [patients] who experienced one episode of depression were candidates for longer-term maintenance treatment," said Charles Reynolds, a physician at the University of Pittsburgh and one of the study's authors. "These data allow us to go one step further and suggest that those with single episodes fare considerably better if they continue use of the medicine that made them well."

The randomized, double-blind trial assigned 116 elderly patients to one of four treatment regimens -- either paroxetine (a selective serotonin reuptake inhibitor) or placebo combined with either monthly psychotherapy or clinical-management sessions -- and followed them for two years or until the recurrence of depressive symptoms. Among those who received paroxetine, 63 percent remained in remission, and among those who received paroxetine plus interpersonal psychotherapy (IPT), 65 percent remained in remission. IPT alone, noted the study, was not statistically effective in preventing a recurrence of depression.