Talking with a psychotherapist is as effective in treating many forms of depression as prescribing a powerful antidepressant drug, according to a major new federal study.
Conducted by the National Institute of Mental Health, the study is the first to measure the effects of two types of psychotherapy -- cognitive behavior and interpersonal -- against drug treatment and a control group. The control group received a placebo, or sugar pill, plus about half an hour per week of "supportive discussion," but not psychotherapy, with a psychiatrist.
At the end of treatment, there were "no significant differences" in reduction of symptoms or "in overall functioning" between patients on the antidepressant imipramine or either form of psychotherapy, the researchers reported in a paper prepared for release Tuesday at the 139th annual meeting of the American Psychiatric Association at the Washington Convention Center.
Although numerous studies have shown that psychotherapy "works" for many types of mental disorders -- from mild or moderate anxieties to phobias and sexual dysfunction -- evaluating psychotherapy is difficult. Several hundred forms of therapy are practiced by thousands of psychotherapists, whose education ranges from medical degrees and doctorates in psychology to master's degrees in social work.
The NIMH study is unique because it examined a large number of depressed patients (some 250 men and women) at three different research sites (George Washington University, the University of Pittsburgh and the University of Oklahoma). The therapists also received special training sessions to standardize the types of treatment performed. About 70 percent of the participants were women. (Approximately 66 percent of depression patients are female.) Participants ranged in age from 21 to 60, with an average age of 35. Ninety percent were white, and 75 percent had attended at least one year of college. They underwent treatment for 16 weeks for at least 50 minutes a week.
In general, the findings suggest that psychotherapy is as good at treating less severe forms of depression as the widely used drug imipramine, an antidepressant with a proven track record for controlling depression. No one knows exactly how imipramine works, but it seems to raise levels in the brain of the neurochemicals norepinephrine and serotonin. People who are depressed have lower levels of these chemicals.
But there were differences in how fast each treatment worked. For instance, imipramine "was somewhat more rapid than the other treatments in reducing depressive symptoms," report psychologist Irene Elkin, coordinator of the study, and her colleagues Tracie Shea, Dr. Stanley Imber, Dr. Stuart Sotsky and John Watkins.
These differences were particularly pronounced between eight and 12 weeks of therapy. But by 16 weeks, "the psychotherapies had caught up with the impiramine condition."
The findings, which researchers cautioned are "still initial," also suggest that one form of therapy, interpersonal, may be particularly effective in treating severe depressions.
Interpersonal therapy focuses on the patient's relationships with other people, such as family members and business associates. A short-term therapy of 12 to 16 weeks, it is oriented toward symptom relief and resolution of the immediate interpersonal difficulties. It is not geared toward personality change. The idea is to develop more successful ways of relating to other people.
Cognitive behavior therapy, on the other hand, seeks to unravel faulty or distorted patterns of thinking, which practitioners of this therapy consider the basis of depression. Also short-term, it is oriented toward reversing extremely negative feelings about oneself, the world and the future. Patients are taught to see the world around them differently. For instance, a move to a new city is to be viewed not as a loss but as an adventure.
The researchers found some differences in results of the psychotherapies at different sites, Elkin said. The results of the impramine were more consistent throughout the varied locations.
"We do not yet know how much variation in results for the two psychotherapies may be due to therapist factors, to patient factors, sites factors or aspects of the patient-therapist match," Elkin said. "Those are questions that we plan to pursue since they are essential to an understanding of the findings for the psychotherapy conditions."
All therapies -- even the placebo combined with just 30 minutes of supportive talking with a psychiatrist -- helped alleviate less severe depression, the study found.
"The pill placebo . . . group did surprisingly well for the less severely depressed patients," Elkin said. Overall, "more than half of all patients achieved recovery in the two psychotherapy treatment groups" and the imipramine group, compared with 29 percent in the placebo group.
The results suggest that the administration of a placebo combined with supportive discussions "may be sufficient to bring about significant reduction in symptoms in the less severely depressed," she said. "But it is not for those who are more severely depressed."