Consistent with previous studies of adolescent alcohol use, genetic influences were found to be important and no gender differences in aetiology were found [3]. Genetic estimates were slightly higher than has been reported, but as the genetic aetiology of adolescent alcohol use has not been studied previously in UK-based samples, it is not clear whether this effect is specific to alcohol use within the CaStaNET sample or to the United Kingdom in general. However, the prevalence rates in CaStaNET were consistent with those reported in large studies of alcohol use in the United Kingdom [2]. Genetic influences were slightly stronger for quantity of alcohol use (a2 = 0.61) than alcohol problem use (a2 = 0.46). This may be because alcohol problem use was assessed as whether the problem use had occurred twice in the last year (rather than the regularity of it occurring), and this may be more influenced by environmental opportunities to drink to excess.
