The Comorbidity and Trauma Study (CATS), a collaboration of investigators at Washington University School of Medicine, the Queensland Institute of Medical Research, and the National Drug and Alcohol Research Centre of the University of New South Wales, examined genetic and environmental factors contributing to liability for heroin dependence using a case-control design. A description of the methods used for data collection has been given in previous reports of phenotypic data (Shand et al. 2010). In addition to case and control subjects recruited after funding was obtained, we include here 25 cases and 25 neighborhood controls from the CATS pilot study for whom other protocols were identical and assessment was comparable.
