Since 94.1% of the CATS6,7,20 opioid dependent participants reported a period of daily injection, we operationalized having had such a period as the population’s normative opioid dependence endpoint (ODE). Comparisons of opioid dependent individuals who differed on daily injection status found substantial phenotypic differences (Supplementary Table 1 and Supplementary Methods). Comparisons of dependent individuals who never injected daily to non-dependent opioid misusers revealed fewer significant differences. Our GWAS analyses compared the ODE group (N=1167 opioid dependent daily injectors) to a group characterized as having opioid use with impeded progression (OUIP) that combined non-dependent opioid misusers (N=88; 69.3% reporting heroin use) and opioid dependent individuals without a history of daily injection (N=73).
