Background: Little is known about the transition from substance abuse to substance dependence.
Objectives: This study aims to estimate the cumulative probability of developing dependence and to identify predictors of transition to dependence among individuals with lifetime alcohol, cannabis, or cocaine abuse.
Methods: Analyses were done for the subsample of individuals with lifetime alcohol abuse (n = 7802), cannabis abuse (n = 2832), or cocaine abuse (n = 815) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Estimated projections of the cumulative probability of transitioning from abuse to dependence were obtained by the standard actuarial method. Discrete-time survival analyses with time-varying covariates were implemented to identify predictors of transition to dependence.
Results: Lifetime cumulative probability estimates indicated that 26.6% of individuals with alcohol abuse, 9.4% of individuals with cannabis abuse, and 15.6% of individuals with cocaine abuse transition from abuse to dependence at some point in their lives. Half of the transitions of alcohol, cannabis, and cocaine dependence occurred approximately 3.16, 1.83, and 1.42 years after abuse onset, respectively. Several sociodemographic, psychopathological, and substance use-related variables predicted transition from abuse to dependence for all of the substances assessed.
Conclusion: The majority of individuals with abuse do not transition to dependence. Lifetime cumulative probability of transition from abuse to dependence was highest for alcohol, followed by cocaine and lastly cannabis. Time from onset of abuse to dependence was shorter for cocaine, followed by cannabis and alcohol. Although some predictors of transition were common across substances, other predictors were specific for certain substances.