Both human laboratory and clinical outpatient studies have established the reliability, validity and time course of the cannabis withdrawal syndrome [26, 27] and the cannabis withdrawal syndrome has been proposed for inclusion in DSM-V [28]. Some US studies suggest that about half of patients in treatment have reported symptoms of the cannabis withdrawal syndrome [23, 29–33]. The main symptoms of cannabis withdrawal are anxiety, irritability, depressed mood, restlessness, disturbed sleep, G-I symptoms, and decreased appetite. Most symptoms begin during the first week of abstinence and resolve after a few weeks.
