Voucher-based Reinforcement Therapy (VBRT) for Homeless, Out of Treatment, Substance-dependent Men who have Sex with Men

Background: Methamphetamine use is endemic among urban gay and bisexual men and other men who have sex with men (MSM), and is correlated with increased rates of HIV and STIs. Homelessness, psychiatric and substance use comorbidities make this population especially vulnerable. VBRT has been shown to be an effective method for reducing drug use and increasing prosocial behaviors. The purpose of this study is to investigate the effectiveness of VBRT among homeless, substance-dependent MSM participating in community HIV prevention programs.

Methods: A randomized control trial of 131 participants assigned to either VBRT or the control condition. Both receive points for attendance, while VBRT participants receive additional points for engaging in drug and alcohol abstinence, and healthy/pro-social behaviors. Assessments conducted at baseline and 7, 9 and 12-month follow-up.

Results: Preliminary analysis shows VRBT participants were 42% more likely to test negative for amphetamines/methamphetamines, alcohol, cocaine and PCP compared to control [OR=1.42 (95%CI=1.22-1.65)]. VBRT participants achieved a higher proportion of clean UA samples (µ_VBRT=60%) than control (µ_ctrl=51%; t₍₁₂₅₎=1.86,p=.065 n.s. trend); and achieved a higher Treatment Effectiveness Score [µ_VBRT=31.4 (24.4)] than control (µ_ctrl=23.0(20.8); t₍₁₂₅₎=2.09, p=.04). Participants in the VRBT condition engaged in more targeted behaviors [µ_VBRT=36.7(28.4)] than those in the control condition (µ_ctrl=20.5 (18.9), t₍₁₂₅₎=2.11, p=.037).

Conclusions/Implications: These preliminary findings support the hypothesis that VBRT can significantly reduce substance use, moving participants toward lower HIV risk behaviors.