Genetic of addiction: common and uncommon factors.

Epidemiological studies strongly suggest that genetic factors operate at all steps of addictions, including vulnerability to initiation, continued use, and propensity to become dependent. Several studies have been popular to investigate the relative contributions of genetic and environmental factors, including the availability of and exposure to a substance, and shared and unique environments. The genetic influence on addiction has proved to be substantial, and heritabilities for most addictive disorders are moderate to high. In this work we evaluate the current status of data that analyzed genetic contribution in addictions.