Matan1,
The issue is overall effectiveness, not in comparison to medication. The following is a quote from the book The Undiscovered Mind:
“One ‘striking’ finding, Elkin said, was the ‘relatively small percentage of patients who remain in treatment, fully recover, and remain completely well throughout the 18-month followup period.’ Only 24 percent of the patients recovered from their depression by the end of the 16-week treatment period and remained free of major symptoms for the next 18 months. The percentage of paitents on each regime who stayed well were as follows: cognitive-behavioral therapy, 30 percent; interpersonal therapy, 26 percent; placebo plus clinical management, 20 percent; imipramine, 19 percent.”
Thus, although CBT appears to be the best treatment for depression out there, it still only produces long-term results in 30% of cases (and I wonder what the effectiveness rate would be if we stretched that out to 3 years instead of 18-months).