What is a common risk factor for substance use disorders?

• A. Genetic predisposition.
• B. Regular exercise.
• C. Strong social support.
• D. High socioeconomic success.

Answer: (B)

Genetic predisposition is a well-established risk factor for substance use disorders. Family, twin, and adoption studies show substantial heritability, with genetics accounting for a meaningful portion of the risk—often around 40–60% depending on the substance. This means that having a family history increases vulnerability due to inherited differences in brain reward pathways, impulse control, and stress response. Importantly, genes interact with the environment: exposure to substances, peer influence, trauma, and chronic stress can amplify or mitigate risk. Protective factors like regular exercise and strong social support help reduce the likelihood of misuse, while high socioeconomic status is not itself a risk factor. In short, a genetic predisposition most commonly contributes to risk for substance use disorders.