Environmental. Risk factors include academic failure, tobacco smoking, unstable or abu- sive family situation, use of cannabis among immediate family members, a family history of a substance use disorder, and low socioeconomic status. As with all substances of abuse, the ease of availability of the substance is a risk factor; cannabis is relatively easy to obtain in most cultures, which increases the risk of developing a cannabis use disorder.
Genetic and physiological. Genetic inﬂuences contribute to the development of canna- bis use disorders. Heritable factors contribute between 30% and 80% of the total variance in risk of cannabis use disorders. It should be noted that common genetic and shared en- vironmental inﬂuences between cannabis and other types of substance use disorders sug- gest a common genetic basis for adolescent substance use and conduct problems.
Cannabis is probably the world’s most commonly used illicit substance. Occurrence of cannabis use disorder across countries is unknown, but the prevalence rates are likely sim- ilar among developed countries. It is frequently among the first drugs of experimentation (often in the teens) of all cultural groups in the United States.
Acceptance of cannabis for medical purposes varies widely across and within cultures.
Cultural factors (acceptability and legal status) that might impact diagnosis relate to dif- ferential consequences across cultures for detection of use (i.e., arrest, school suspensions, or employment suspension). The general change in substance use disorder diagnostic cri- teria from DSM-IV to DSM-5 (i.e., removal of the recurrent substance-related legal prob- lems criterion) mitigates this concern to some degree.
Biological tests for cannabinoid metabolites are useful for determining if an individual has recently used cannabis. Such testing is helpful in making a diagnosis, particularly in milder cases if an individual denies using while others (family, work, school) purport con- cern about a substance use problem. Because cannabinoids are fat soluble, they persist in bodily ﬂuids for extended periods of time and are excreted slowly. Expertise in urine test- ing methods is needed to reliably interpret results.
Functional Consequences of Cannabis Use Disorder
Functional consequences of cannabis use disorder are part of the diagnostic criteria. Many areas of psychosocial, cognitive, and health functioning may be compromised in relation to cannabis use disorder. Cognitive function, particularly higher executive function, ap- pears to be compromised in cannabis users, and this relationship appears to be dose de- pendent (both acutely and chronically). This may contribute to increased difficulty at school or work. Cannabis use has been related to a reduction in prosocial goal-directed ac- tivity, which some have labeled an amotivational syndrome, that manifests itself in poor school performance and employment problems. These problems may be related to perva- sive intoxication or recovery from the effects of intoxication. Similarly, cannabis-associated problems with social relationships are commonly reported in those with cannabis use dis- order. Accidents due to engagement in potentially dangerous behaviors while under the inﬂuence (e.g., driving, sport, recreational or employment activities) are also of concern.
Cannabis smoke contains high levels of carcinogenic compounds that place chronic users at risk for respiratory illnesses similar to those experienced by tobacco smokers. Chronic cannabis use may contribute to the onset or exacerbation of many other mental disorders.
In particular, concern has been raised about cannabis use as a causal factor in schizophrenia and other psychotic disorders. Cannabis use can contribute to the onset of an acute psy- chotic episode, can exacerbate some symptoms, and can adversely affect treatment of a major psychotic illness.