Alcohol use, especially at binge levels, is associated with sexual HIV-risk behavior, but the mechanisms through which alcohol increases sexual risk taking – specifically, how alcohol intoxication influences decisions about condom use – are not well understood. This study uses two methods – delay discounting, the devaluation of future consequences as a function of delay to their occurrence, and probability discounting, a process in which a consequence is devalued because it is uncertain or probabilistic – to examine those mechanisms.

Researchers supervised 23 non-dependent alcohol users (13 male, 10 female; with a mean age of 25.3 years old) who consumed alcohol (1 g/kg) or placebo orally in two separate experimental sessions. During the sessions, participants completed tasks examining delay and probability discounting of hypothetical condom-protected sex.

Results showed that alcohol decreased the likelihood that participants would wait to have condom-protected sex versus having immediate, unprotected sex. Alcohol also decreased the likelihood that participants would use an immediately available condom given a specified risk level of sexually transmitted infection. These findings suggest that delay and probability discounting are critical, but heretofore unrecognized, processes that may mediate the relations between alcohol use and HIV risk.