LAUSR

Purpose Overdose-focused harm reduction can be incorporated into treatment to prevent overdose and improve bystander response after treatment. This study sought to examine harm reduction knowledge among persons who inject drugs (PWID) and those using by other methods (non-PWID) to inform overdose-related psychoeducation during substance use disorder (SUD) treatment. Methods Injection drug use history in the 30 days before residential SUD treatment was characterised among 248 PWID and 409 non-PWID who participated in the Safety and Health Intervention Project and used (via any route) substances that can be injected. We compared patterns of substance use, overdose experience, and knowledge of naloxone and cardiopulmonary resuscitation (CPR) in PWID and non-PWID using simple statistics (frequencies and chi-squared or Fisher’s exact tests). Results PWID were more 2.6 times more likely than non-PWID to use prescription opioids in the year prior to treatment (74.0% vs. 28.0%, p<0.0001) and 8.4 times more likely to use street opioids (i.e., heroin, 91.2% vs. 10.9%, p<0.0001). Consistent with a higher risk for overdose when injecting, PWID more commonly experienced overdose in the month prior to treatment (10.9% versus 1.7% of non-PWID, p<0.0001). PWID had more commonly heard of naloxone (85.1% PWID vs. 35.0% of non-PWID, p<0.0001) and correctly identified the purpose of naloxone (80.2% of PWID and 30.8% of non-PWID, p<0.0001) compared to non-PWID. Nearly all participants had heard of CPR (99.2% PWID vs. 98.5% non-PWID, p=0.7) and correct identification of its purpose did not differ by group (54.8% PWID vs 57.2% non-PWID, p=0.6). Conclusions PWID more often had recent overdose experiences, but had greater knowledge of naloxone than non-PWID. Significance Approximately 40%–60% of persons relapse within the first year after SUD treatment. Despite the lower risk of overdose, non-PWID may benefit from SUD treatment-based overdose bystander education, given the lack of prior exposure.