Cognitive Behavioral Therapy, Ketamine, and Combination Treatment for Depression: Impressions of Credibility in Participants with Self-Reported Depressive Symptoms.

Ketamine, a novel treatment for depression, has generated considerable interest and research. Few experiments address lay impressions of the credibility of ketamine treatment relative to another popular intervention for depression, CBT. Over 500 participants with depressive symptoms read descriptions of CBT, ketamine, and a treatment that combined the two. Descriptions included pros and cons of each approach. Participants found the combination treatment more credible than ketamine but no better than CBT alone. They rated the credibility of CBT alone significantly higher than ketamine alone. Participants with psychotherapy experience tended to view ketamine as less credible than those who did not report previous psychotherapy. Depression scores did not covary with credibility ratings for any treatment. Despite media coverage and Internet claims, potential clients are cautious about ketamine. These results suggest that providing descriptions of treatments might help reveal important information about their credibility to potential clients. Extended work assessing impressions of many approaches to the treatment of psychopathology and other problems appears justifiable. Given established links between credibility and treatment outcome, additional research on individual differences in perceptions of ketamine and varied treatments for depression seems warranted.