The results of any attempt to rate the effectiveness of clinical methods--as opposed to the individual effectiveness of practitioners--is best summed up by the dodo bird in Alice's Adventures in Wonderland: "Everybody has won and all must have prizes." In 1936, Saul Rosenzweig invoked the dodo's words to describe the equivalent success of diverse psychotherapies. It has since been called the "dodo bird verdict" and has proven to be one of the most replicated findings in the psychotherapy literature--no approach can reliably make a greater claim to effectiveness than any other.
Perhaps the best publicized study to confirm this idea that all techniques are created equal is the landmark 1989 Treatment of Depression Collaborative Research Project, widely viewed as the most ambitious and methodologically sophisticated outcome study ever undertaken. This NIMH-funded project, which involved both psychiatrists and psychologists at multiple cites around the country, randomly assigned 250 depressed participants to four different treatments: Aaron Beck's cognitive therapy--an approach that seeks to reduce depressive symptoms by challenging irrational and distorted attitudes; Gerald Klerman and Myrna Weissman's interpersonal therapy--which focuses on developing more effective strategies for dealing with "here and now" interpersonal problems; treatment with antidepressant medication; and, finally, a placebo approach called "clinical management," which included a pill placebo plus support and encouragement. After all the effort that went into designing a study that represented the state-of-the-art in outcome research, the investigators were stunned by their own findings. Overall, the four treatments--including placebo--worked with about the same effectiveness.
Recent advancements in statistical methodology, particularly metanalytic studies, which allow researchers to comb through the vast clinical literature and draw conclusions from huge collections of data, lend even further credence to the dodo bird verdict. In psychotherapy researcher Bruce Wampold's comprehensive 1996 review of the therapy-outcome literature, some 277 studies conducted from 1970 to 1995 were analyzed--with particular attention given to the presumably more methodologically sophisticated research of recent years--to determine which therapeutic models have yielded the most robust results. This comprehensive review once again verified that no approach has reliably demonstrated superiority over any other. "Why," Wampold asks, "[do] researchers persist in attempts to find treatment differences, when they know that these effects are small?"
The Client as Partner
So, if empirically supported treatments aren't what makes psychotherapy beneficial to clients, what is? Even though Rosenzweig addressed this question 65 years ago, his conclusion still applies today. Writing in the American Journal of Orthopsychiatry, he argued that all approaches appear to be equally effective, so there must be some larger common factors in operation that overshadow any presumed differences between techniques. What are these factors? The answer isn't really a mystery. The real key to the success or failure of therapy, as Rosenzweig and many other therapists over the years have argued, is the resources a client brings into the room.