Aims: To examine the course and the predictors of the persistence of cannabis dependence.
Methods: Through cannabis outlets
and chain referral, a prospective enriched community cohort of 207 young adults (aged 18-30) with DSM-IV cannabis dependence
at baseline (T0) was formed and followed-up after 1.5 (T1) and 3 (T2) years. The presence of cannabis dependence, cannabis-related
problems, functional impairment and treatment was assessed using the Composite International Diagnostic Interview (CIDI 3.0)
and the Sheehan Disability Scale (SDS). Predictors of persistence were lifetime cannabis abuse and dependence symptoms, cannabis
use characteristics, distant vulnerability factors (e.g. childhood adversity, family history of psychological/substance use
problems, impulsivity, mental disorders), and proximal stress factors (recent life events, social support).
groups were distinguished: persistent dependent (DDD: 28.0%), stable non-persistent (DNN: 40.6%), late non-persistent (DDN:
17.9%) and recurrent dependent (DND: 13.5%). At T2, persisters (DDD) reported significantly more (heavy) cannabis use and
cannabis problems than non-persisters (DNN/DDN/DND). Treatment seeking for cannabis-related problems was rare, even among
persisters (15.5%). The number (OR = 1.23 (1.03-1.48)) and type (‘role impairment' OR = 2.85 (1.11-7.31), ‘use despite problems'
OR = 2.34 (1.15-4.76)) of lifetime cannabis abuse/dependence symptoms were the only independent predictors of persistence
with a total explained variance of 8.8%.
Conclusions: Persistence of cannabis dependence in the community is low, difficult
to predict, and associated with a negative outcome. The substantial proportion of stable non-persisters suggests that screening
and monitoring or low-threshold brief interventions may suffice for many non-treatment-seeking cannabis-dependent people.
However, those with many lifetime abuse/dependence symptoms may benefit from more intensive interventions.