Low prevalence of risk drinking in adolescents and young adults with autism spectrum problems.

Individuals with Autism Spectrum Disorder (ASD) have high rates of "comorbidity". Research on concurrent substance use (disorder) in ASD, however, is scarce and findings have been inconsistent. This study aims at assessing the prevalence of risk drinking in adolescent and young adult twins with and without autism spectrum problems. Data from a Swedish longitudinal nationwide twin study were analyzed. Across three age groups of 15- (N = 10,050), 18- (N = 7,931) and 24-year-olds (N = 2,882) prevalence rates of risk drinking were compared between twins with and without an ASD proxy diagnosis and between different ASD subgroups based on comorbid proxies for attention-deficit/hyperactivity disorder (ADHD) and/or Learning Disorder (LD). ASD, ADHD, and LD were assessed using the Autism-Tics, ADHD, and other Comorbidities inventory (A-TAC), and risk drinking was captured by the Alcohol Use Disorders Identification Test (AUDIT; age 18 and 24) and another set of self-report questions (age 15). In each age group, the prevalence of risk drinking in ASD was lower than in individuals without ASD, yet increasing continuously with age. Exploratory subgroup ASD analyses showed a trend towards risk drinking being more common among individuals with co-existing ADHD or LD problems than among those without "comorbidity", although sample sizes were too small to draw any certain conclusions. This study indicates low prevalence of risk drinking in adolescents and young adults with autism spectrum problems and highlights the need for further research on alcohol use in individuals with ASD and comorbid disorders.