Participants were interviewed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule DSM-IV version (AUDADIS-IV) (Grant et al., 2001), a fully-structured instrument designed for experienced lay interviewers. The AUDADIS covers non-medical cannabis use and also detailed questions on the criteria for DSM-IV cannabis abuse and dependence, combined through computer algorithms (Compton et al., 2004) to generate DSM-IV(American Psychiatric Association, 1994) diagnoses. (While the term “cannabis” includes marijuana and other forms, e.g., hashish, we use the term “marijuana abuse/dependence” throughout given the small proportion of hashish relative to all cannabis used in the U.S. (~1%) (Mehmedic et al.)). Good to excellent reliability and validity of marijuana abuse/dependence diagnoses (κ=0.62-0.78) in the AUDADIS-IV have been extensively documented in both U.S. and international samples, including clinical reappraisals conducted by psychiatrists in clinical and general population samples, and in several countries as part of the World Health Organization/National Institutes of Health International Study on Reliability and Validity (Chatterji et al., 1997; Cottler et al., 1997; Grant et al., 1995; Hasin et al., 1997; Nelson et al., 1999; Pull et al., 1997; Ustun et
