Dominant situational determinants of sexual risk behaviour in gay men

Objective: To examine the interplay between situational, social and psychological factors in gay men's decisions about HIV risk behaviour, using multiple hypothetical situations. Method: The sample included 79 gay men from Sydney recruited through flyers, press advertisements or personal contact at gay venues. Subjects were presented with 20 hypothetical situations graphically on a computer, which included different levels of attraction to partner, intoxication, attractiveness to partner, condom availability, desire for anal sex by subject, insistence of partner on using a condom and time constraints in each situation. Subjects used a computerized graphic rating scale to indicate the likelihood of unprotected anal sex in each situation, the frequency with which they had experienced the hypothetical situation in real life and satisfaction with their response. The probability of having unsafe anal sex in any given situation was the dependent variable. All other variables were predictors. Results: A vector of predictors accounted for 30% of the variance (r = 0.54). Ratings of the probability of anal sex increased with the frequency that subjects had experienced hypothetical situations in real life, attraction to partner, attractiveness to partner and time elapsed since real life experience similar to the hypothetical one. Ratings of the probability of anal sex decreased with condom availability. Conclusions: Our results suggest that interventions must address the way that individuals interact with their partner and their environment in order to be successful.