Cannabis withdrawal was not included in DSM-IV because of a lack of evidence. Since then, the reliability and validity of cannabis withdrawal has been demonstrated in preclinical, clinical, and epidemiological studies (126, 127, 130–135). The syndrome has a transient course after cessation of cannabis use (135–138) and pharmacological specificity (139–141). Cannabis withdrawal is reported by up to one-third of regular users in the general population (131, 132, 134) and by 50%–95% of heavy users in treatment or research studies (133, 135, 142, 143). The clinical significance of cannabis withdrawal is demonstrated by use of cannabis or other substances to relieve it, its association with difficulty quitting (135, 142, 144), and worse treatment outcomes associated with greater withdrawal severity (133, 143). In addition, in latent variable modeling (30), adding withdrawal to other substance use disorders criteria for cannabis improves model fit.
