Alcohol-induced blackouts at age 20 predict the incidence, maintenance and severity of alcohol dependence at age 25: a prospective study in a sample of young Swiss men.

Background And Aims: Alcohol-induced blackout (AIB) is a common alcohol-related adverse event occurring during teenage years. Although research provides evidence that AIB predicts acute negative consequences, less is known about the associations of AIB with chronic consequences, such as alcohol dependence (AD). This study estimated the associations between an experience of AIB at age 20 and the incidence, maintenance and severity of AD at age 25 among Swiss men.

Design: Prospective cohort study with 5.5 years separating baseline and follow-up.

Setting: Switzerland.

Participants: Swiss male drinkers (n = 5469, age 20 at baseline) drawn from the Cohort Study on Substance Use Risk Factors (C-SURF).

Measurements: Self-report questionnaires assessing AIB, AD, alcohol (drinking volume, binge drinking), cigarette and cannabis use, several risk factors (sensation-seeking, family history of problematic alcohol use, age of first alcohol intoxication) and socio-demographic variables.

Findings: Generalized estimating equation models with and without adjustment for risk factors, including alcohol use and socio-demographics, showed that AIB at age 20 significantly predicted the incidence of AD at age 25 in men without AD at age 20 [odds ratio (OR) = 2.52, 95% confidence interval (CI), unadjusted = 2.04, 3.11, P < 0.001; fully adjusted, OR = 1.47, 95% CI = 1.13, 1.91, P = 0.004], maintenance of AD in men with AD at age 20 (unadjusted, OR = 1.82, 95% CI = 1.12, 2.95, P = 0.015; fully adjusted, OR = 1.66, 95% CI = 1.00, 2.76, P = 0.048] and AD severity [unadjusted incidence rate ratio (IRR) = 1.89, 95% CI = 1.69, 2.11, P < 0.001; fully adjusted, IRR = 1.20, 95% CI = 1.10, 1.31, P < 0.001].

Conclusions: Among Swiss men, alcohol-induced blackout at age 20 predicts the development, maintenance and severity of alcohol dependence at age 25.