['Controversy exists regarding the inclusion of cannabis withdrawal as an indicator of dependence in the next revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD). This study contrasted the concurrent and predictive validity of three operational definitions of cannabis withdrawal in a sample of treated adolescents.', 'Prospective study of treated adolescents with 1-year follow-up.', 'Adolescents (n=214) were recruited from intensive out-patient treatment programs for substance abuse, and followed at 1 year (92% retention). Youth who were included in the analyses reported regular cannabis use.', 'The number of DSM-IV cannabis abuse and dependence symptoms at baseline and 1-year follow-up, past year frequency of cannabis use at baseline and follow-up, and periods of abstinence at 1-year follow-up. Cannabis withdrawal was defined based on (i) the presence of two or more cannabis withdrawal symptoms; (ii) a definition proposed by Budney and colleagues (2006) that requires four or more withdrawal symptoms (four-symptom definition); and (iii) the use of latent class analysis to identify subgroups with similar cannabis withdrawal symptom profiles.'] Does cannabis withdrawal predict severity of cannabis involvement at 1-year follow-up among treated adolescents?