A growing body of research suggests that to treat major depression, changing the way people think about things is as effective as changing their body chemistry through drugs.

Now comes research by psychologists at Penn and Vanderbilt University that shows that cognitive therapy has long-lasting effects that may make it more cost-effective than medication in more serious cases of depression as well.

The study, conducted by Robert DeRubeis, professor of psychology here, and Steven D. Hollon, professor of psychology at Vanderbilt, tracked severely depressed patients—people depressed almost to the point of hospitalization—over 16 months. Subjects received four months of acute treatment—either medication or cognitive therapy sessions—followed by an additional year of follow-up treatment for those whose condition improved.

The study, presented at the American Psychiatric Association convention in May, showed that 75 percent of the patients receiving cognitive therapy avoided a relapse into depression, as opposed to 60 percent of those on medication and 19 percent of those who received a placebo.

“This showed that cognitive therapy was as effective as medication in the short term and that cognitive therapy provided a superior benefit over one year’s time than medication,” DeRubeis said.

It also provided a superior benefit to the wallet. “In the short run, cognitive therapy costs more,” DeRubeis said, “but over the entire 16 months, medication therapy was more expensive.”

The study further bolsters the case for cognitive therapy, which was invented by University Professor Emeritus of Psychology Aaron Beck in the 1960s.

It should also interest cost-conscious health insurers, who currently favor antidepressants because of their presumed cost advantage. “I think that HMOs and insurance companies will look at results like ours and see there are other options besides antidepressant medications [for treatment of depression], and this is [also] becoming clear for a number of other disorders,” such as panic disorder, obsessive-compulsive disorder, social phobia and even mild cases of schizophrenia, DeRubeis said.

But before managed-care plans rush to put all their clients on a cognitive therapy regime, DeRubeis advises that drugs still have their place. For starters, drugs don’t ask potentially disturbing questions about a patient’s innermost thoughts and attitudes.

Quality control is also an issue. “[Patients] can count on the fact that the medications are produced in the same way,” he said. “The quality of the therapist may vary, but the quality of the drugs is consistent”—although he adds that some therapists are better at prescribing drugs than others as well.

The next logical step for DeRubeis and Hollon is to study cognitive therapy’s effectiveness over an even longer term. The pair have recently received funding from the National Institutes of Health to begin a three-year comparative study of cognitive and drug therapies, in which patients will receive intensive treatment for 18 months and then no treatment at all for the remainder of the study.