Psychological Predictors of Alcohol Use and Misuse in Adults with Autism Spectrum Conditions

Background: Alcohol misuse is associated with a variety of adverse physical, psychological and social consequences. The limited existing research on substance use (including alcohol use) in adults with autism spectrum conditions (ASC) has yielded mixed findings, with some studies concluding that autism is a protective factor against substance use and others suggesting that autism may increase an individual’s risk for substance misuse. Qualitative and anecdotal evidence suggests that demographic factors, co-morbid mental health difficulties and autistic traits may contribute to alcohol use in this population.

Objectives: This study sought to quantitatively investigate psychological predictors of alcohol use and misuse in a sample of adults with ASC using a web-based cross-sectional survey.

Methods: Participants were 237 adults with ASC who were recruited via social media, internet forums and clinical databases. An online survey was used to obtain data on demographic information, autistic traits, depression, anxiety, social anxiety, mental wellbeing and alcohol use. All relevant constructs were measured using gold-standard, well-validated self-report measures. The sample was divided into three groups (non-drinkers, non-hazardous drinkers and hazardous drinkers) and multinomial logistic regression models were used to explore associations between alcohol use and independent variables.

Results: Thirty percent of participants were classified as non-drinkers, 54.8% as non-hazardous drinkers and 15.2% as hazardous drinkers. Using comparative data from the general population, the proportions of non-drinkers and hazardous drinkers among autistic adults were higher than those for neurotypical adults (20.9% and 14% respectively; X²(1)=69.15, p <.001). Compared to autistic non-hazardous drinkers, autistic non-drinkers were more likely to be female (OR: 2.57; 95% CI: 1.32-5.00) and had higher levels of autistic traits (OR: 1.02; 95% CI: 1.00-1.04), depression (OR: 1.05; 95% CI: 1.00-1.09), anxiety (OR: 1.06; 95% CI: 1.01-1.12) and social anxiety (OR: 1.01; 95% CI: 1.00-1.02). Compared to autistic non-hazardous drinkers, autistic hazardous drinkers also had higher levels of autistic traits (OR: 1.02; 95% CI: 1.00-1.04), depression (OR: 1.09; 95% CI: 1.04-1.16), anxiety (OR: 1.10; 95% CI: 1.03-1.17) and social anxiety (OR: 1.02, 95% CI: 1.00-1.03) and lower levels of mental wellbeing (OR: 0.95; 95% CI: 0.91-0.99). These results demonstrate a U-shaped pattern among autistic adults, with both non-drinkers and hazardous drinkers scoring higher than non-hazardous drinkers on levels of autistic traits, depression, anxiety and social anxiety.

Conclusions: Non-hazardous use of alcohol is associated with fewer autistic traits and positive mental health outcomes in adults with ASC, while abstinence and hazardous alcohol consumption are associated with more autistic traits and higher levels of depression, anxiety and social anxiety. Alcohol use in adults with ASC is multifaceted and complex and this group should not be considered a homogenous population. Screening for alcohol use should form part of routine healthcare assessments for ASC given that a significant proportion of these individuals may be misusing alcohol. An individualised approach should be taken to explore the unique contribution of factors involved in alcohol use for those identified to be at-risk, paving the way for tailored treatment and support.