Factors that Contribute to Cannabis Abuse and/or Dependence among Young Adults
Cannabis use, abuse and dependence (CAD) among young adults is an important public health issue, and problem cannabis use has been reported as a risk factor for the use of other illicit drugs. In addition, twin studies have found heritability estimates for cannabis dependence that range from 45% to 58%. This study sought to determine the magnitude of the contribution from environmental variables to offspring cannabis dependence in a design that controls for familial vulnerability. Investigators used data from a study of 725 twin members of the Vietnam Era Twin Registry, 720 of their biological offspring (ages 18-32), and 427 mothers.
Findings show that after adjusting for genetic and shared environmental risk for CAD, cannabis abuse and dependence was significantly more likely among male offspring. Offspring CAD was associated with siblings’ use of illicit drugs (with or without cannabis, but not cannabis only), as well as friends’ and peers’ use of drugs. Female gender was associated with reduced risk of young adult CAD.
Scherrer J, Grant J, Duncan A, Pan H, Waterman B, Jacob T, Haber J, True W, Heath A, and Bucholz K. Measured environmental contributions to cannabis abuse/dependence in an offspring of twins design. Addictive Behaviors October 2008;33(10):1255-1266.
This study was partly funded by HSR&D. Dr. Scherrer was supported by an HSR&D Career Development Award and is part of the St. Louis VA Medical Center; Drs. Jacob and Haber are part of the VA Palo Alto Health Care System.