Curvilinear associations between sexual orientation and problematic substance use, behavioural addictions and mental health among young Swiss men

Background and aims: It is well documented that individuals with a minority sexual orientation face greater risks of problematic substance use (e.g. heavy episodic drinking, alcohol use disorder) and mental health problems. Far less is known about how that risk varies within this population and their risk of behavioural addictions. This study estimated the risks of problematic substance use, behavioural addiction and poor mental health across the spectrum of sexual orientation. Sample and method: A sample of young Swiss men (N = 5294; mean ag e= 25.5, SD = 1.25; representative of 21 of Switzerland's 26 cantons) completed a self-reporting questionnaire on sexual orientation (attraction, 5-point scale) and criterion variables: problematic substance use (e.g. alcohol, cigarettes, cannabis and other illegal drugs), behavioural addictions (gambling, gaming, cybersex, internet, smartphone, work, exercise) and indicators of mental health (e.g. depression, stress). Curvilinear associations between sexual orientation (heterosexual, mostly-heterosexual, bisexual, mostly-homosexual or homosexual individuals) and criterion variables were explored using fractional polynomial regressions. Results: Although there were differences across criterion variables, in general, the highest risks of problematic substance use, behavioural addictions and mental health problems were estimated for mostly-heterosexual, bisexual or mostly-homosexual men, followed by homosexual men, and with heterosexual men facing the lowest risk. Discussion and conclusion: Aggregating the spectrum of sexual orientations into two or three distinct groups blurs important internal group differences. Outcome-specific explanations beyond minority stress and biphobia are necessary to understand the pathways between sexual orientation and risky behaviours. Considering sexual orientation is important to provide targeted healthcare prevention and interventions.