Analysis of data from a prospective New Zealand birth cohort of nearly 1000 individuals has shown that family history is a strong predictor of AUD and is associated with a more recurrent course and worse impairment [15]. It is well known that an important risk factor is having an alcoholic parent. It has now been firmly established, largely through numerous studies in thousands of twin pairs and some adoption studies, that the heritability (the genetic component of the variance) of all addictive substances lies between 40–70%; the heritability of alcoholism is around 50% [1,16]. Therefore genetic and environmental risk factors for the development of alcoholism are equally important. Interestingly, results from twin studies suggest a theoretical dissection of genetic risk in that there may be two pathways for genetic influence: an early onset pathway driven in part by genetic risk for externalizing disorders and a later, adult onset pathway driven by genetic risk factors that are specific for AUD [17,18].
