NCJ Number
183353
Journal
Addiction Volume: 94 Issue: 7 Dated: July 1999 Pages: 981-993
Date Published
July 1999
Length
13 pages
Annotation
This study estimated the contribution of genetic and environmental factors to adolescent tobacco, alcohol, and other substance use.
Abstract
The sample consisted of 327 monozygotic and 174 like-sex dizygotic twin pairs born in Minnesota and aged 17-18 years at the time of assessment. Biometrical methods were used to estimate the contribution of additive genetic, shared, and non-shared environmental factors to adolescent substance use. As part of a day-long psychological assessment, adolescent twins completed a computerized substance-use interview to determine whether they had ever used tobacco, alcohol, or other illicit drugs. The heritability for the liabilities to tobacco, alcohol, and other drug use was estimated to be 59 percent, 60 percent, and 33 percent among males, and 11 percent, 10 percent, and 11 percent among females; however, the gender differences were not statistically significant. Estimates of shared environmental effect were substantial and insignificantly higher among females (71 percent, 68 percent, and 36 percent, respectively) than among males (18 percent, 23 percent, and 23 percent, respectively). The covariation among the three substance use phenotypes could be accounted for by a common underlying substance-use factor. Estimates of the contributions of genetic, shared environmental, and non-shared environmental factors to variance in this factor were 23 percent, 63 percent, and 14 percent, respectively. These findings add to the growing behavioral genetic literature that indicates adolescent initiation of substance use, a powerful predictor of adult substance use, is influenced primarily by environmental rather than genetic factors. 5 tables, 2 figures, and 48 references