Background: Double-blind placebo-controlled trials are the academic standard for clinical psychopharmacology research.
Aims: To identify the potential defects of current double-blind procedures in trials involving antidepressants and to investigate whether safeguards for blindness protection are used.
Method: We reviewed the literature and devised a short seven-item checklist for evaluating the quality of blindness protection. We performed a computerised search for 1998 to identify the placebo-controlled studies that evaluated the efficacy of an antidepressant. The checklist was used to assess all traceable antidepressant trials published in 1998.
Results: Relevant criticisms question the blindness procedures. The available methods which may bolster blindness are very seldom used.
Conclusions: Improvement in the blindness procedures used for antidepressant trials is necessary, feasible and measurable.