The onset of cannabis use disorder can occur at any time during or following adolescence, but onset is most commonly during adolescence or young adulthood. Although much less frequent, onset of cannabis use disorder in the preteen years or in the late 205 or older can occur. Recent acceptance by some of the use and availability of “medical marijuana” may increase the rate of onset of cannabis use disorder among older adults.
Generally, cannabis use disorder develops over an extended period of time, although the progression appears to be more rapid in adolescents, particularly those with pervasive conduct problems. Most people who develop a cannabis use disorder typically establish a pattern of cannabis use that gradually increases in both frequency and amount. Cannabis, along with tobacco and alcohol, is traditionally the first substance that adolescents try.
Many perceive cannabis use as less harmful than alcohol or tobacco use, and this percep- tion likely contributes to increased use. Moreover, cannabis intoxication does not typically result in as severe behavioral and cognitive dysfunction as does significant alcohol intox— ication, which may increase the probability of more frequent use in more diverse situa- tions than with alcohol. These factors likely contribute to the potential rapid transition from cannabis use to a cannabis use disorder among some adolescents and the common pattern of using throughout the day that is commonly observed among those with more severe cannabis use disorder.
Cannabis use disorder among preteens, adolescents, and young adults is typically ex- pressed as excessive use with peers that is a component of a pattern of other delinquent behaviors usually associated with conduct problems. Milder cases primarily reﬂect con- tinued use despite clear problems related to disapproval of use by other peers, school ad- ministration, or family, which also places the youth at risk for physical or behavioral consequences. In more severe cases, there is a progression to using alone or using through— out the day such that use interferes with daily functioning and takes the place of previ- ously established, prosocial activities.
With adolescent users, changes in mood stability, energy level, and eating patterns are commonly observed. These signs and symptoms are likely due to the direct effects of can- nabis use (intoxication) and the subsequent effects following acute intoxication (coming down), as well as attempts to conceal use from others. School-related problems are com— monly associated with cannabis use disorder in adolescents, particularly a dramatic drop in grades, truancy, and reduced interest in general school activities and outcomes.
Cannabis use disorder among adults typically involves well-established patterns of daily cannabis use that continue despite clear psychosocial or medical problems. Many adults have experienced repeated desire to stop or have failed at repeated cessation attempts. Milder adult cases may resemble the more common adolescent cases in that cannabis use is not as frequent or heavy but continues despite potential significant consequences of sustained use. The rate of use among middle-age and older adults appears to be increasing, likely because of a cohort ef— fect resulting from high prevalence of use in the late 1960s and the 19705.
Early onset of cannabis use (e.g., prior to age 15 years) is a robust predictor of the de- velopment of cannabis use disorder and other types of substance use disorders and mental disorders during young adulthood. Such early onset is likely related to concurrent other externalizing problems, most notably conduct disorder symptoms. However, early onset is also a predictor of internalizing problems and as such probably reﬂects a general risk factor for the development of mental health disorders.
Temperamental. A history of conduct disorder in childhood or adolescence and antiso- cial personality disorder are risk factors for the development of many substance-related disorders, including cannabis-related disorders. Other risk factors include externalizing or internalizing disorders during childhood or adolescence. Youths with high behavioral disinhibition scores show early-onset substance use disorders, including cannabis use dis- order, multiple substance involvement, and early conduct problems.