Twin studies provide substantial evidence that genetic factors contribute to the etiology of SUDs. Across studies, the weighted mean estimates of SUD heritability—the proportion of variability in risk in a population due to genetic differences between individuals—range from 40% to 70% across different psychoactive substances3–5. The abuse of cocaine may be more heritable than that of other substances. Otherwise, heritability estimates for SUD for most other psychoactive substances in populations of European origin fall largely between 40 and 55%—similar to or greater than that seen for most common chronic biomedical diseases afflicting Western populations.
