The potential impact of recruitment method on sample characteristics and treatment outcomes in a psychosocial trial for women with co-occurring substance use disorder and PTSD

Background: Recruitment method can impact the sample composition of a clinical trial and, thus, the generalizability of the results, but the importance of recruitment method in substance use disorder trials has received little attention. The present paper sought to address this research gap by evaluating the association between recruitment method and sample characteristics and treatment outcomes in a substance use disorder trial. Methods: In a multi-site trial evaluating Seeking Safety (SS), relative to Women's Health Education (WHE), for women with co-occurring PTSD (either sub-threshold or full PTSD) and substance use disorders, one site assessed the method by which each participant was recruited. Data from this site (n = 106), which recruited participants from newspaper advertising and clinic intakes, were analyzed. Results: Participants recruited through advertising, relative to those from the clinic, had significantly higher levels of baseline drug use and higher rates of meeting DSM-IV-TR criteria for full PTSD. Results suggest that the effectiveness of SS in decreasing PTSD symptoms was greater for participants recruited through advertising relative to those recruited from the clinic. Conversely, the results revealed a significant treatment effect in the clinic-recruited participants, not seen in the advertising-recruited participants, with SS, relative to WHE, participants being more likely to report past week drug use during the follow-up phase. Conclusion: Recruitment method may impact sample composition and treatment effects. Replication of this finding would have important implications for substance use disorder efficacy trials which often utilize advertising to recruit participants. (C) 2011 Elsevier Ireland Ltd. All rights reserved.