The Effectiveness of Voucher-based Reinforcement Therapy on Homeless, Non-treatment Seeking, Substance-dependent MSM

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Date(s) - Aug 7, 2008
12:00 PM - 1:00 PM

St. Anne’s Conference Center


Presented by: 

Rhodri Dierst-Davies

M.P.H. Friends Research Institute, Inc.


Hosted by the Los Angeles Collaborative HIV/AIDS Public Health Research Center :

Mr. Dierst-Davies will present preliminary findings from the VIPS (Voucher-based Incentives in a Prevention Setting) study, which is investigating the effectiveness of Contingency Management (CM) among homeless, out-of-treatment, substance-dependent MSM who participate in a community-based HIV prevention program. Participants (N=131) were randomized into either the CM (n=64) or control (n=67) condition. Those in the CM condition had greater overall attendance than control participants (51% vs. 44%). CM participants achieved a higher mean proportion of urine samples negative for several substances (amphetamines, methamphetamines, alcohol, cocaine and PCP) than control participants (14.2 (S.D.=11.0) vs.10.4 (S.D.=9.7); p=.039), and greater mean Treatment Effectiveness Score than control participants (29.6 (S.D.=22.9) vs. 22.4 (S.D.=20.1), p=.06 n.s. trend). CM participants also had more 3-consecutive clean UA samples in a row compared to controls (2.43 (S.D.=3.37) vs.1.45 (S.D.=2.66), p=.068 n.s. trend). Similarly, participants in the CM condition engaged in more targeted behaviors than control participants (41.5 (S.D.=37.1) vs. 26.2 (S.D.=22.8), p=.005). These preliminary findings support the hypothesis that CM can reduce alcohol and drug use and increase prosocial behaviors, thereby, contributing to the impact of lower-intensity health education/risk reduction programs.