Addictions Counselor Practice Exam

Genetic factors contribute substantially to risk for substance use disorders. In this context, heritability describes how much of the difference in liability to addiction across individuals in a population is due to genetic differences. Research across twin and family studies consistently points to a substantial genetic influence, with estimates commonly in the 40–60% range. This means that about half of the variation in susceptibility in the population can be attributed to genetics, while the rest arises from environmental factors and gene–environment interactions. It’s important to note that this is a population-level statistic, not a precise prediction for any single person, and the exact percentage can vary by substance and population.