Genetic and Familial Environmental Influences on the Risk for Drug Abuse: A National Swedish Adoption Study.
CONTEXT: Prior research suggests that drug abuse (DA) is strongly influenced by both genetic and familial environmental factors. No large-scale adoption study has previously attempted to verify and integrate these findings. OBJECTIVE: To determine how genetic and environmental factors contribute to the risk for DA. DESIGN: Follow-up in 9 public databases (1961-2009) of adopted children and their