How many subjects with major depressive disorder meet eligibility requirements of an antidepressant efficacy trial?

OBJECTIVE: To evaluate the generalizability of the results of antidepressant efficacy trials by determining how many subjects with DSM-IV major depressive disorder who apply for entry into such trials are ultimately enrolled.
METHOD: The screening results of 378 subjects who inquired about participating in 1 of 2 separate antidepressant efficacy trials performed at Rhode Island Hospital between 1997 and 2002 were reviewed. The number of subjects who enrolled, as well as the reasons for exclusion of those who did not meet eligibility requirements, were determined.
RESULTS: Of the 378 inquiries, 186 subjects expressed interest and received a current major depressive disorder diagnosis. From this sample, 27 (14.5%) were ultimately enrolled in 1 of the 2 antidepressant trials. The most common reasons for exclusion were bipolar disorder (17.2%), drug or alcohol abuse (15.6%), mild depression (14.0%), medical contraindication (12.9%), and the use of prohibited psychotropic medications (12.4%).
CONCLUSION: The majority of subjects with major depressive disorder who apply to participate in an antidepressant efficacy trial do not meet eligibility requirements. When prescribing antidepressants, clinicians should bear in mind that the results of these trials may only be directly applicable to a small subset of patients treated in clinical practice.