Antidepressant Efficacy Trials: Questions Raised

Article excerpt

NEW YORK -- Participants in antidepressant efficacy trials are not representative of patients in clinical practice, Dr. Mark Zimmerman said in a poster presentation at the annual meeting of the American Psychiatric Association.

Individuals in the community who would be excluded on the basis of comorbidity or suicidality differ significantly from study populations in demographic, clinical, and psychosocial aspects. This discrepancy raises questions of how the findings of such trials should be interpreted and how antidepressants should be labeled and promoted, he said.

"Antidepressant efficacy trials [AETs] are generally limited to the subset of patients with the greatest likelihood of demonstrating drug-placebo differences, yet medications are approved and marketed without acknowledging the generalizability issue," said Dr. Zimmerman of Brown University, Providence, R.I.

Earlier research that applied common AET exclusion criteria to clinical samples found that although there was variability in the conditions set by different trials, individuals who would have been allowed to participate represented a minority of the patients treated for major depressive disorder in a community-based outpatient practice.

Dr. Zimmerman and his associates compared the demographic, clinical, and psychosocial characteristics of patients who would have been included in most AETs with the characteristics of those who would have been excluded on various grounds.

Patients were evaluated with diverse instruments, including the Schedule for Affective Disorders and Schizophrenia, the Hamilton Rating Scale for Depression, and the Structured Interview for DSM-IV Personality Disorders.

The study population--599 individuals who had been seen in the outpatient practice of Rhode Island Hospital's department of psychiatry--had the following characteristics: Two-thirds were female, 88% were white, and 77% were educated at the high school level or above.

Based on four exclusion criteria (score less than 20 on the Hamilton Rating Scale for Depression, significant suicidal ideation, current substance abuse or dependence, and concurrent anxiety disorder), 79% (476 patients) would not have been allowed to participate in an AET. …