Comparing the dynamic course of heroin, cocaine, and methamphetamine use over 10 years.

To examine dynamic changes in drug-use trajectories over time we analyzed episode types and predictors of quitting use over the 10 years following drug-use initiation for 1797 heroin, cocaine, and methamphetamine (meth) users. Most episodes reflected high use and incarceration, however these events occurred more frequently among heroin and meth users. Quitting was predicted by current treatment and self-help participation among meth (RR 2.57, 1.79-3.70; 2.57, 1.80-3.67) and cocaine (RR 2.00, 1.42-2.81; 2.10, 1.63-2.72) users, and by a history of quitting for meth users (RR 1.11, 1.06-1.17). Quitting was less likely among all users under legal supervision (RR 0.55-0.69) and among heroin (RR 0.66, 0.45-0.97) and meth users (RR 0.73, 0.60-0.89) with an early drug-use onset. Relative to cocaine or meth use, heroin use was characterized by persistent use at a high-level which was often only interrupted by incarceration. While quitting drug use can be facilitated by treatment and/or self-help participation, few people had these experiences in the 10 years following first use.