Dong H, Hayashi K, Singer J, et al. - The longitudinal trajectories of injection drug use were examined and the associated factors were sought. Using the Vancouver Injection Drug Users Study and AIDS Care Cohort to evaluate the Exposure to Survival Services study, researchers obtained data of two prospective cohorts including 2,057 participants who reported having used illicit drugs via injection in the past 6 months at the baseline visit in Vancouver, Canada between 1996 and 2017. During a median follow up 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%). The trajectories were noted to be correlated with the following factors: daily heroin injection, binge injection drug use, age, not being in a stable relationship and year of study enrollment.