Assessing the prevalence of non-medical prescription opioid use in the Canadian general adult population: evidence of large variation depending on survey questions used

Shield KD, Ialomiteanu A, Fischer B, Rehm J. Assessing the prevalence of non-medical prescription opioid use in the Canadian general adult population: evidence of large variation depending on survey questions used. BMC Psychiatry. 2013; 13: 6.