Cannabis Use Disorder 515
chotic episode, can exacerbate some sympto ms, and can adversely affect treatment of a
major psychotic illness.
Differential Diagnosis
Nonproblematic use of cannabis. The distinction between nonproblematic use of can-
nabis and cannabis use disorder can be difficult  to make because social, behavioral, or psy-
chological problems may be difficult to attribut e to the substance, especially in the context
of use of other substances. Also, denial of heavy cannabis use and the attribution that can-
nabis is related to or causing substantial problems are common among individuals who
are referred to treatment by others (i.e., sch ool, family, employer, criminal justice system).
Other mental disorders. Cannabis-induced disorder may be characterized by symp-
toms (e.g., anxiety) that resemble primary mental disorders (e.g., gene ralized anxiety dis-
order vs. cannabis-induced anxiety disorder, with generalized anxiety, with onset during
intoxication). Chronic intake of cannabis can produce a lack of motivation that resembles
persistent depressive disorder (dysthymia). Acute adverse reactions to cannabis should be
differentiated from the symptoms of panic di sorder, major depressive disorder, delusional
disorder, bipolar disorder, or schizophrenia , paranoid type. Physical examination will
usually show an increased pulse and conjunctiv al injection. Urine toxicological testing can
be helpful in making a diagnosis.
Comorbidity
Cannabis has been commonly thought of as a “gateway” drug because individuals who
frequently use cannabis have a much greater lifetime probabili ty than nonusers of using
what are commonly considered more dangerou s substances, like opioids or cocaine. Can-
nabis use and cannabis use disorder are highly comorbid with other substance use disor-