The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) is a two-wave face-to-face survey conducted by the National Institute on Alcohol Abuse and Alcoholism. Wave 1 was conducted from August 2001 to September 2003 and included 43 093 respondents, aged 18 years or older. The sample represented the civilian, non-institutionalized adult population of the USA. The sample has been described previously by Grant et al. (2003). Of these, 39 959 were eligible for follow-up in wave 2 and 34 653 completed wave 2 interviews from August 2004 to September 2005. PTSD was assessed only in wave 2. The wave 2 response rate was 86.7% (Grant et al. 2005).
