The alleged bias in efficacy trials of antidepressant medications is contradicted by the findings of a study published in the March American Journal of Psychiatry. Recent reports in the professional and lay press have charged that design flaws in efficacy trials invalidate the positive results. The critiques also suggest that psychotherapy and even placebos are equally effective for acute and maintenance treatment of unipolar depression.

Frederick M. Quitkin, M.D., and his colleagues at the Columbia University College of Physicians and Surgeons in New York City examined the studies criticized in the recent reports. After evaluating the methodology of those studies and doing an aggregate analysis of their findings, the New York investigators concluded that they are valid. They pointed out that arguments in the recent critiques cite outdated literature citations and analyze the study results inadequately.

However, Quitkin and his colleagues agreed with the critics who warn about the threat of bias to the integrity of efficacy research. For example, it is possible for investigators to pierce the double blind when rating responses to medications. Guessing that a research subject has received active medication is especially likely to occur when the response is strong. If clinical outcomes are ambiguous, they noted, a reasonable scientist "may use different criteria when assessing patients guessed to be taking drug or placebo."

But psychotherapy efficacy studies are subject to similar types of bias because of the investigator’s allegiance to a particular form of therapy, they suggest. "Investigators of all allegiances should not be complacent about the possibility of bias affecting their studies."

The criticism of drug studies, particularly in the popular press, is cause for concern, according to the New York researchers. They warn that the critical reports may discourage depressed people from seeking effective treatment.

Quitkin and his colleagues recommend that, rather than examining old studies, investigators of various theoretical orientations should collaborate on "mega-trials." Findings from those large-scale studies could form the basis for developing clinical guidelines.