Diversity in randomized clinical trials of depression: A 36-year review.

Historically, authors reporting the results of randomized clinical trials (RCTs) to address mental health problems have insufficiently described sample characteristics pertaining to the ethnic/racial, linguistic, socioeconomic, and immigrant backgrounds of participants. RCTs have also had inadequate representation of participants from diverse backgrounds. This study reports on the trends in the reporting and representation of various sample demographic characteristics in RCTs of psychotherapy and other psychosocial interventions for depression over a 36-year period, and on the extent to which ethnicity, in particular, is considered in the analyses of treatment effects. A total of 342 trials (85.1% comprised of adult samples), representing 61,283 participants, are summarized in the review. Reporting for ethnicity and socioeconomic indicators improved over time, and RCTs for depression have also increasingly included significant numbers of ethnic minority and low-income groups. However, trials are far more likely to exclude, rather than include, linguistic minorities, and have not enrolled a meaningful number of Asian American, Native Hawaiian/Pacific Islander, Native American/Native Alaskan and multi-ethnic participants. Finally, treatment effects are almost never presented separately across racial/ethnic groups and ethnicity moderation analyses are only sporadically conducted. These findings have implications for generalizability, policy, journal reporting guidelines, and dissemination and implementation.