Risk Factors for Mild, Moderate, and Severe Alcohol Use Disorder (AUD) in a sample of adult substance users: Implications for DSM-5 AUD Classification

Though risk factors of Alcohol Use Disorder (AUD) have been well-studied, information is lacking on whether clinical characteristics differentiate between the three levels of severity (mild, moderate, severe) that were established for the first time in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). Therefore, in this study, we examined the association between alcohol consumption, mental and physical health, and functional impairment with the three DSM-5 AUD severity levels among adults age 18+ (N=588) pre-screened for problems with at least one substance. Participants recruited between 2016-2019 completed measures of AUD, harmful alcohol use, psychiatric conditions, and mental, physical, and social functional impairment. For each predictor, a multinomial logistic regression model was used to evaluate the association with a four-level AUD outcome (mild, moderate, severe, vs none), controlling for sociodemographic characteristics and other substance use. Twelve-month prevalence of none, mild, moderate, and severe DSM-5 AUD was 34.0%, 12.2%, 13.4%, and 40.3%, respectively. Participants reported a mean of 11.3 (SD=9.90) days of alcohol use in the past month, nearly half (48.0%) perceived to have a major problem with alcohol, and 61.4% met the threshold for harmful drinking. Multinomial logistic regression demonstrated that compared to the reference group (no AUD), all three AUD severity levels were associated with drinking frequency, problematic, and harmful alcohol use. However, only severe AUD was associated with personality disorders: (AOR=1.91, 95% CI=1.28, 2.86), MDD (AOR= 2.44, 95% CI= 1.62, 3.66) or PTSD (AOR= 1.65, 95% CI= 1.00, 2.71),. Similarly, only severe AUD was associated with impaired physical (AOR= 1.63, 95% CI= 1.01, 2.61), mental (AOR= 1.80, 95% CI= 1.16, 2.79), and social functioning (AOR= 1.87, 95% CI= 1.39, 2.51). This study adds to existing literature on clinical correlates of AUD by further elucidating the risk factors of the different AUD severity groups, while also highlighting an important, differential observation wherein measures of psychiatric disorders and functional impairment were only associated with severe AUD. The study suggests that the DSM-5 category of severe AUD most closely corresponds to AUD cases often found in secondary or tertiary treatment settings, and that cases of mild or moderate AUD may warrant less intensive treatment approaches. Future investigations should seek to examine the validity of the DSM-5 AUD three-level severity distinction by using longitudinal designs to evaluate change in mental health and functioning over time, along with their association with AUD severity classification.