Delay-discounting among homeless, out-of-treatment, substance-dependent men who have sex with men.

ABSTRACT

BACKGROUND: Impulsivity is associated with substance use; however, to date, impulsivity has not been characterized among a sample of homeless, non-treatment seeking, substance-dependent men who have sex with men (MSM). OBJECTIVES: The aim of this study was to utilize the delay-discounting instrument to assess impulsive behaviors among a subsample of homeless, non-treatment seeking, substance-dependent men who have sex with men (S-D MSM) enrolled in a randomized, controlled, contingency management (CM) trial. METHODS: Twenty S-D MSM participants from the CM parent study were matched on age and ethnicity to 20 non-substance-dependent, non-homeless control participants using propensity scores (N=40) and were administered the delay-discounting procedure. RESULTS: Although discounting values decreased rapidly with time in both groups, the S-D MSM participants consistently discounted rewards more steeply than controls (p=.05), particularly at all intermediate measured timeframes. The S-D MSM participants also presented greater median discounting rates (k values) compared with the control group (m(S-D MSM)=2.39 (SD=3.72) vs. m(ctrl)=1.27 (SD=3.71), p≤.01). CONCLUSION: This work extends existing findings of increased delay-discounting among substance-dependent individuals to homeless, substance-dependent, non-treatment seeking MSM. SCIENTIFIC SIGNIFICANCE: A better understanding of the prevalence of delay-discounting type behaviors among homeless, substance-dependent MSM can be used to inform the development of tailored substance abuse interventions for this high-risk population.