Alcohol consumption, sex, and use of psychotropic substances among male Hong Kong-mainland China cross-border substance users

The study investigated the prevalence and associated factors for co-occurrence of psychotropic substance use, alcohol consumption and sexual activities among substance users. Totally, 1167 Hong Kong Chinese males aged 18–30 having used substances in mainland China in the last year were identified. Of them, 72.5% and 42.7% respectively reported having consumed alcohol and engaged in sexual activities in conjunction with the last episode of substance use. Among those using substances exclusively in mainland China, multivariate analyses showed that having friends who frequently used substances in China (OR = 3.18) and being accompanied by friends in the last episode of substance use (OR = 2.31) were associated with alcohol consumption; older age (OR = 2.01), higher education level (OR = 2.31), alcohol consumption (OR = 2.72), belief that substance use increased sexual potency (OR = 2.81) and use of multiple types of psychotropic substances in China (OR = 2.94) were significantly associated with having sex in conjunction with the last episode of using psychotropic substances. Cross-border psychoactive substance use often co-occurs with alcohol and sex. High levels of risk are involved. Different types of preventive programs need to be integrated.