Cannabis Use Disorder 513
Development and Course
The onset of cannabis use disorder can occur at  any time during or following adolescence,
but onset is most commonly during adolescenc e or young adulthood. Although much less
frequent, onset of cannabis use disorder in the preteen years or in the late 20s or older can
occur. Recent acceptance by some of the us e 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 ad olescents, 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 traditiona lly 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 sig nificant 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 disord er among some adolescents and the common
pattern of using throughout the day that is commonly ob served among those with more
severe cannabis use disorder.
Cannabis use disorder among preteens, adoles cents, 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 pr oblems. Milder cases primarily reflect con-
tinued use despite clear problems related to di sapproval of use by other peers, school ad-