Principal investigators Robert J. DeRubeis of Penn and Steven D. Hollon of Vanderbilt and their colleagues will present the work Thursday, May 23 at the annual conference of the American Psychiatric Association in Philadelphia.
"This will be a surprising, controversial finding for many psychiatric professionals," said DeRubeis, professor and chair of psychology at Penn. "Most believe quite strongly in the efficacy of medication, and psychiatric treatment guidelines call unequivocally for medication in cases of severe depression."
Compared to past research on severely depressed patients - those depressed nearly enough to require hospitalization - DeRubeis and Hollon's study was unusually comprehensive in its size, 240 patients in Philadelphia and Nashville, and in its duration, 16 months.
"We looked at depression somewhat differently than prior studies," said Hollon, professor of psychology at Vanderbilt. "The question that has most often been asked in studies is, 'What gets people better faster?' We asked, 'What will keep depression away over the long term?'"
The study by DeRubeis, Hollon and colleagues involved a four-month period of acute treatment followed by an additional year of treatment for those who showed improvement in the initial phase. Among those who continued into the second phase of the study, 75 percent of patients who underwent cognitive therapy avoided a relapse, compared to 60 percent of patients on medication and 19 percent of those receiving a placebo pill.
"Statistically, both cognitive therapy and medication were more effective than a placebo, and a brief course of cognitive therapy was better than a similarly brief course of medication in the yearlong continuation phase," DeRubeis said. "These results suggest that even after termination, a brief course of cognitive therapy may offer enduring protection comparable to that provided by ongoing medication."
DeRubeis, Hollon and colleagues also found that cognitive therapy enjoys a long-term cost benefit compared to drugs. During the 16 months, treatment with medication cost an average of $2,590, compared with $2,250 for cognitive therapy. This gap grew with time, since antidepressants must be administered continually to be effective.
"Some proponents of medication for severely depressed patients have suggested that cognitive therapy is impractical on the basis of cost," DeRubeis said. "Our study indicates that isn't true, especially over the long term."
Developed at Penn in the 1960s, cognitive therapy encourages depressed patients to challenge the judgments and misperceptions that underlie their despair - views such as "I'm a bad person and don't deserve to have any fun" or "I'll never get that job, so I won't even apply," DeRubeis said. Therapists explore these harmful ideas with patients, encouraging them to test the misperceptions that shape their negative feelings. Prior studies have shown that in most cases, even short-term cognitive therapy brings patients to regard the damaging hypotheses as invalid.
DeRubeis and Hollon's colleagues in the study include Jay D. Amsterdam and John P. O'Reardon of the Department of Psychiatry in Penn's School of Medicine; Paula R. Young, formerly of Penn's Department of Psychiatry; and Richard C. Shelton, Ronald M. Solomon and Margaret L. Lovett of Vanderbilt's Department of Psychiatry. The study was funded by the National Institute of Mental Health and GlaxoSmithKline.