Founder of Health Rising and Phoenix Rising
Depression was CBT's original reason for being but a meta-analysis suggests that it's not even very good for that. The odd thing is that it seemed to work better than it does not.
Looking at the effect of CBT on adults' depression scores using either of these scales (i.e. by comparing scores pre vs. post therapy), the researchers found a linear and steady reduction in the therapy's apparent efficacy over time. Simply put, CBT doesn't seem to be helping reduce depression symptoms as much today as it used to when it was first developed in the 1970's.
So, why is CBT apparently losing it's power to help people with depression? Johnsen and Friborg can only speculate. One suggestion they have is that CBT is somehow losing its placebo effect over time:
In the initial phase of the cognitive era, CBT was frequently portrayed as the gold standard for the treatment of many disorders. In recent times, however, an increasing number of studies ... have not found this method to be superior to other techniques. Coupled with the increasing availability of such information to the public, including the Internet, it is not inconceivable that patients’ hope and faith in the efficacy of CBT has decreased somewhat, in recent decades. Moreover, whether widespread knowledge of the present meta-analysis results might worsen the situation, remains an open question."