By: National Institute on Drug Abuse
"Why do some people become addicted while others don't? Family studies that include identical twins, fraternal twins, adoptees, and siblings suggest that as much as half of a person’s risk of becoming addicted to nicotine, alcohol, or other drugs depends on his or her genetic makeup. Pinning down the biological basis for this risk is an important avenue of research for scientists trying to solve the problem of drug addiction."
