The findings are published in Alcoholism: Clinical and Experimental Research.
Lead study author Richard R. Rose of Indiana University stated, "The key finding was that the more drinking-related problems experienced by an adolescent at age 18, the greater the likelihood that adolescent would be diagnosed with alcoholism seven years later, at age 25." He went on to explain, "The analysis of co-twins ruled out factors such as parental drinking and household atmosphere as the source of the association, because twins jointly experience these." Rose said that because twin teens in the study had the same parental, environmental and genetic factors, the results provide strong evidence that drinking behavior at age 18 is a strong predictor for drinking behavior at age 25.
The study involved 597 twins enrolled in long-term Finnish study of twins. At age 18 the twins took the Rutgers Alcohol Problem Index (RAPI), which is a self-administered questionnaire designed to measure alcohol drinking related problems. Rose said the RAPI is one of the most widely used assessments of problematic teen drinking. Study participants were later interviewed in-person at age 25 to assess alcohol dependence.
The study found that 52% of teens had RAPI scores reflecting problematic drinking at age 18, and those results held at age 25 when the young adults were tested for alcohol dependence. 46.2 % met the criteria for alcohol dependence and 1.5% for alcohol abuse. RAPI scores in late teen years "robustly predict alcohol diagnoses in early adulthood. Accordingly, our results also provide new evidence that one pathway to problem drinking in early adulthood is a direct one from problem drinking in adolescence," according to the study. Rose says the findings show that teen drinking problems can chart a course to problems with alcohol in young adulthood.
