Cannabis use disorder

Cannabis use disorder (CUD), also known as cannabis addiction or marijuana addiction, is defined in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and ICD-10 as the continued use of cannabis despite clinically significant impairment. Cannabis use is sometimes comorbid for other mental health problems, such as mood and anxiety disorders, and discontinuing cannabis use is difficult for some users. Psychiatric comorbidities are often present in dependent cannabis users including a range of personality disorders. Based on annual survey data, some high school seniors who report smoking daily (nearly 7%, according to one study) may function at a lower rate in school than students that do not. The sedating and anxiolytic properties of tetrahydrocannabinol (THC) in some users might make the use of cannabis an attempt to self-medicate personality or psychiatric disorders. Prolonged cannabis use produces both pharmacokinetic changes (how the drug is absorbed, distributed, metabolized, and excreted) and pharmacodynamic changes (how the drug interacts with target cells) to the body. These changes require the user to consume higher doses of the drug to achieve a common desirable effect (known as a higher tolerance), reinforcing the body's metabolic systems for eliminating the drug more efficiently and further down-regulating cannabinoid receptors in the brain. Cannabis users have shown decreased reactivity to dopamine, suggesting a possible link to a dampening of the reward system of the brain and an increase in negative emotion and addiction severity. Cannabis users can develop tolerance to the effects of THC. Tolerance to the behavioral and psychological effects of THC has been demonstrated in adolescent humans and animals. The mechanisms that create this tolerance to THC are thought to involve changes in cannabinoid receptor function. One study has shown that between 2001–2002 and 2012–2013, the use of marijuana in the US doubled.