Dong H, et al. - Longitudinal trajectories of injection drug use were investigated as well as their associated factors were determined. Researchers analyzed data from the Vancouver Injection Drug Users Study and AIDS Care Cohort to appraise Exposure to Survival Services study, two prospective cohorts involving people who inject drugs in Vancouver, Canada, between 1996 and 2017. Following a total of 2057 participants for a median of 113.4 months, they identified five trajectories: persistent high frequency injection (507, 24.6%); high frequency injection with late decrease (374, 18.2%); gradual cessation (662, 32.2%); early cessation with late relapse (227, 11.0%); and early cessation (287, 14.0%). Over the study period, nearly 25% of the participants remained high-frequency injectors.