Addiction is a diverse group of common, complex diseases that are linked to some degree by common genetic and environmental etiologic factors. They are often chronic, with relapsing-remitting courses.
Genetic studies and other analyses that clarify the origin of addiction help destigmatize addiction and lead to more rapid treatment. Knowledge of genetic factors in etiology and treatment response may allow individualization of prevention and treatment and identification of new therapeutic targets.
Both genetic and environmental variables contribute to the initiation of substance use and the transition from use to addiction. Addictions are moderately to highly heritable. Family, adoption, and twin studies show that an individual’s risk tends to be proportional to the degree of genetic relatedness to an addicted relative.
The heritability of addictive disorders ranges from 0.39 for hallucinogens to 0.72 for cocaine. From a developmental perspective, an important view of the shifting balance in the importance of genetic and environmental influences has been obtained. The Virginia Twin Study showed that in early adolescence, the onset and use of nicotine, alcohol, and cannabis are more strongly determined by family and social factors, but that these gradually become less important during young and middle adulthood, when the effects of genetic factors become maximal, and decrease somewhat with age.
Clin Pharmacol Ther.: Genes and Addictions
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