Can the randomized controlled trial literature generalize to nonrandomized patients?

Abstract

To determine the extent to which published randomized controlled trials (RCTs) of psychotherapy can be generalized to a sample of outpatients, the authors matched information obtained from charts of patients who had been screened out of RCTs to inclusion and exclusion criteria from published RCT studies. Most of the patients in the sample who had primary diagnoses represented in the RCT literature were judged eligible for at least 1 RCT. However, many patients in the sample with substance use disorders or social anxiety disorder were not eligible for at least 2 RCTs. Common reasons that patients did not match with at least 2 published RCTs for psychotherapy included (a) patients were in partial remission, (b) patients failed to meet minimum severity or duration criteria, (c) patients were being treated with antidepressant medication, and (d) the disorder being studied was not primary (mostly for social anxiety patients). The implications of these findings for future research and clinical practice are discussed.