A comparison of depressed patients in randomized versus nonrandomized trials of antidepressant medication and...

Clinicians and researchers have questioned whether participants in randomized control trials (RCTs) are representative of patients in the broader clinical population.

We compared the demographic, clinical, and personality characteristics of patients (N=256) with major depressive disorder (MDD) receiving antidepressant medication or interpersonal therapy as part of an RCT investigation (n=105) versus in a clinic (n=151). The RCT and clinic protocols were identical with the exception of recruitment procedures (advertisement versus physician referral) and assignment to treatment (randomized versus nonrandomized).

No significant differences emerged between the RCT participants and clinic patients for sex, age, marital status, and education. Overall, clinic patients were no more severely depressed compared to RCT participants; there was, however, a significant interaction effect. Response rates were significantly higher for RCT participants versus clinic patients. Those participating in the RCT scored significantly higher on a personality scale assessing preference for novel experiences compared to those in the clinic.

Differences in clinical and personality variables between those receiving treatment for MDD as part of an RCT versus in a clinic exist; however, the clinical significance of these differences remains in question, as these variables were unrelated to treatment outcome.