Differences in severity of heroin dependence by route of administration: the importance of length of heroin use

To explore differences in the severity of heroin dependence by route of adm inistration, we interviewed 909 heroin users in three Spanish cities. Depen dence was measured with the severity dependence scale (SDS). No major diffe rences in the severity of heroin dependence were detected among users with 5 or more years of heroin use (long-term users), but differences were found among newer users (SDS mean scores, 7.3 in heroin injectors; 7.9 in smoker s and 4.6 in sniffers; P = 0.006), especially those with fewer than 3 years of use. Similar differences by route of administration were found when fre quency of heroin use (days/month) was considered rather than severity of de pendence. However, in the latter case major differences were also found amo ng long-term users. These findings suggest that the route of administration probably influences the rate of progression to dependence but has little i nfluence on the long-run level of dependence. They also help explain some a spects of the transition between routes of heroin administration, which is occurring in different areas. (C) 2001 Elsevier Science Ireland Ltd. All ri ghts reserved.