How can we successfully recruit depressed people? Lessons learned in recruiting depressed participants to a multi-site trial of a brief depression intervention (the 'CLASSIC' trial)

Background: There are enormous problems in recruiting depressed people into randomised controlled trials (RCTs), with numerous studies consistently failing to recruit to target (Sully et al., Trials 14:166, 2013). Given the high prevalence of-and disability associated with-depression, it is important to find ways of effectively recruiting to RCTs evaluating interventions. This study aimed to test the feasibility of using a self-referral system to recruit to a brief intervention in a multi-site trial, the CLASSIC trial of self-confidence workshops for depression. In that trial, participants referred themselves to a depression intervention with a positive non-diagnostic title of 'self-confidence', given the close relationship of depression and self-esteem (Horrell et al., Br J Psychiatry 204:222-233, 2014).

Method: We analysed uptake and retention rates by recruitment to the study, attendance at the workshops and follow-up rates. However, because of the rapid rate of recruitment, we decided to pause the trial and revise our original single-site research protocol in months 5-6. We report findings under three main headings: recruitment rates for the 12 months of the project before and after the pause; data regarding attendance at the workshops before and after the pause; and the follow-up rates before and after the pause.

Results: We recruited 459 participants within 12 months, representing 38 participants recruited per month. Improved uptake of the intervention and retention after the development of multi-site research protocols are reported.

Discussion: Based on previous evidence from RCT recruitment among depressed participants, our recruitment rate demonstrates that a self-referral system using a non-diagnostic title of self-confidence is a successful recruitment method. The implications of rapid recruitment using a self-referral system are described, including the impact on uptake of the intervention as well as participant retention. Because of the potential for recruiting many participants quickly, research teams need to be adequately resourced and the oversight committees prepared to meet at shorter intervals with RCTs of brief interventions.

Short conclusion: Self-referral to a brief intervention for depression with a non-diagnostic title can be a very effective way of recruiting depressed people into trials. However, there are also some challenges.

Trial registration: ISRCTN, ISRCTN26634837 . Registered on 10 June 2010.