Cannabis use disorder

Cannabis use disorder
Other names Cannabis addictions, marijuana addiction
Specialty Psychiatry

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.[1][2]

Signs and symptoms[edit]

Cannabis use and abuse has symptoms that affect behavior, physical, cognitive, and psychosocial aspects of a person’s life. Symptoms include agitation, bloodshot eyes, challenges in problem solving, and paranoia.[3]

Cannabis use is associated with comorbid mental health problems, such as mood and anxiety disorders, and discontinuing cannabis use is difficult for some users.[4] Psychiatric comorbidities are often present in dependent cannabis users including a range of personality disorders.[5]

The use of cannabis at a young age such as the teenage years, can have serious impacts on depression and anxiety in youth and later in life.[6] There is evidence that cannabis use during adolescence, at a time when the brain is still developing, may have deleterious effects on neural development and later cognitive functioning.[7] The brain is not completely developed until a person reaches the age range of 22-27. Excessive use of marijuana can cause harm to this development.[8] Based on an annual survey data 7 percent of high school seniors that smoke daily function at a lower rate in school than students that do not.[9] The sedating and anxiolytic properties of THC in some users might make the use of cannabis an attempt to self-medicate personality or psychiatric disorders.[10]

Dependency[edit]

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 downregulating cannabinoid receptors in the brain.[11]

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.[12]

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.[13][14] The mechanisms that create this tolerance to THC are thought to involve changes in cannabinoid receptor function.[13]

According to the National Cannabis Prevention and Information Centre in Australia, a sign of cannabis dependence is that an individual spends noticeably more time than the average recreational user recovering from the use of or obtaining cannabis. For some, using cannabis becomes a substantial and disruptive part of an individual’s life and he or she may exhibit difficulties in meeting personal obligations or participating in important life activities, preferring to use cannabis instead. People who are cannabis dependent have the inability to stop or decrease using cannabis on their own.[15] One study has shown that between 2001-2002 and 2012-2013, the use of marijuanna in the US doubled.[16]

Cannabis dependence develops in about 9% of users, significantly less than that of heroin, cocaine, alcohol, and prescribed anxiolytics,[17] but slightly higher than that for psilocybin, mescaline, or LSD.[18] Of those who use cannabis daily, 10–20% develop dependence.[19]

Withdrawal[edit]

Cannabis withdrawal symptoms can occur in one half of patients in treatment for cannabis use disorders. These symptoms include dysphoria (anxiety, irritability, depression, restlessness), disturbed sleep, gastrointestinal symptoms, and decreased appetite. Most symptoms begin during the first week of abstinence and resolve after a few weeks.[4] According to a study in the U.S., 12.1% of heavy cannabis users showed cannabis withdrawal as defined by the DSM-5, and this was associated with significant disability as well as mood, anxiety and personality disorders.[20]

Cause[edit]

Cannabis addiction is often due to prolonged and increasing use of the drug. Increasing the strength of the cannabis taken and an increasing use of more effective methods of delivery often increase the progression of cannabis dependency. It can also be caused by being prone to becoming addicted to substances, which can either be genetically or environmentally acquired.[21]

Risk factors[edit]

Certain factors are considered to heighten the risk of developing cannabis dependence and longitudinal studies over a number of years have enabled researchers to track aspects of social and psychological development concurrently with cannabis use. Increasing evidence is being shown for the elevation of associated problems by the frequency and age at which cannabis is used, with young and frequent users being at most risk.[22]

The main factors in Australia, for example, related to a heightened risk for developing problems with cannabis use include frequent use at a young age; personal maladjustment; emotional distress; poor parenting; school drop-out; affiliation with drug-using peers; moving away from home at an early age; daily cigarette smoking; and ready access to cannabis. The researchers concluded there is emerging evidence that positive experiences to early cannabis use are a significant predictor of late dependence and that genetic predisposition plays a role in the development of problematic use.[23]

High risk groups[edit]

A number of groups have been identified as being at greater risk of developing cannabis dependence and, in Australia, for example, have been found to include adolescent populations, Aboriginal and Torres Strait Islanders and people suffering from mental health conditions.[7]

Adolescents[edit]

Young people are at greater risk of developing cannabis dependence because of the association between early initiation into substance use and subsequent problems such as dependence, and the risks associated with using cannabis at a developmentally vulnerable age.[7]

Diagnosis[edit]

Cannabis use disorder is recognized in the fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5),[24] which also added cannabis withdrawal as a new condition.[25]

In the 2013 revision for the DSM-5, DSM-IV abuse and dependence were combined into cannabis use disorder. The legal problems criterion (from cannabis abuse) has been removed, and the craving criterion was newly added, resulting in a total of 11 criteria. These are: hazardous use, social/interpersonal problems, neglected major roles, withdrawal, tolerance, used larger amounts/longer, repeated attempts to quit/control use, much time spent using, physical/psychological problems related to use, activities given up and craving. For a diagnosis of DSM-5 cannabis use disorder, at least 2 of these criteria need to be present in the last 12 month period. Additionally, three severity levels have been defined: mild (2-3 criteria), moderate (4-5 criteria) and severe (six or more criteria) cannabis use disorder.[26]

As a time and cost saving alternative to extensive diagnostic interviews, several short scales for the screening for cannabis-related problems have been developed. Among the most frequently used screeners are the Cannabis Use Disorders Identification Test (CUDIT), Severity of Dependence Scale (SDS), Cannabis Abuse Screening Test (CAST) and Problematic Use of Marijuana (PUM).[27]

Treatment[edit]

Clinicians differentiate between casual users who have difficulty with drug screens, and daily heavy users, to a chronic user who uses multiple times a day.[10] In the US, as of 2013, cannabis is the most commonly identified illicit substance used by people admitted to treatment facilities.[19] Demand for treatment for cannabis use disorder increased internationally between 1995 and 2002.[28] In the United States, the average adult who seeks treatment has consumed cannabis for over 10 years almost daily and has attempted to quit six or more times.[18]

No medications have been found effective for cannabis dependence as of 2014,[29][needs update] but psychotherapeutic models hold promise.[4]

Treatment options for cannabis dependence are far fewer than for opiate or alcohol dependence. Most treatment falls into the categories of psychological or psychotherapeutic, intervention, pharmacological intervention or treatment through peer support and environmental approaches.[23] Screening and brief intervention sessions can be given in a variety of settings, particularly at doctor’s offices, which is of importance as most cannabis users seeking help will do so from their general practitioner rather than a drug treatment service agency.[30]

The most commonly accessed forms of treatment in Australia are 12-step programmes, physicians, rehabilitation programmes, and detox services, with inpatient and outpatient services equally accessed.[31] In the EU approximately 20% of all primary admissions and 29% of all new drug clients in 2005, had primary cannabis problems. And in all countries that reported data between 1999–2005 the number of people seeking treatment for cannabis use increased.[32]

Psychological[edit]

Psychological intervention includes cognitive behavioral therapy (CBT), motivational enhancement therapy (MET), contingency management (CM), supportive-expressive psychotherapy (SEP), family and systems interventions, and twelve-step programs.[4]

Evaluations of Marijuana Anonymous programs, modelled on the 12-step lines of Alcoholics Anonymous and Narcotics Anonymous, have shown small beneficial effects for general drug use reduction.[medical citation needed] In 2006, the Wisconsin Initiative to Promote Healthy Lifestyles implemented a program that helps primary care physicians identify and address marijuana use problems in patients.[33]

Medication[edit]

As of 2012, there is no medication that has been proven effective for treating cannabis use disorder; research is focused on three treatment approaches: agonist substitution, antagonist, and modulation of other neurotransmitter systems.[4] More broadly, the goal of medication therapy for cannabis use disorder centers around targeting the stages of the addiction: acute intoxication/binge, withdrawal/negative affect, and preoccupation/anticipation.[34]

For the treatment of the withdrawal/negative affect symptom domain of cannabis use disorder, medications may work by alleviating restlessness, irritable or depressed mood, anxiety, and insomnia.[35] Bupropion, which is a norepinephrine–dopamine reuptake inhibitor, has been studied for the treatment of withdrawal with largely poor results.[35] Atomoxetine has also shown poor results, and is as a norepinephrine reuptake inhibitor, though it does increase the release of dopamine through downstream effects in the prefrontal cortex (an area of the brain responsible for planning complex tasks and behavior).[35] Venlafaxine, a serotonin–norepinephrine reuptake inhibitor, has also been studied for cannabis use disorder, with the thought that the serotonergic component may be useful for the depressed mood or anxious dimensions of the withdrawal symptom domain.[35] While venlafaxine has been shown to improve mood for people with cannabis use disorder, a clinical trial in this population actually found worse cannabis abstinence rates compared to placebo.[35] It’s worth noting that venlafaxine is sometimes poorly tolerated, and infrequent use or abrupt discontinuation of its use can lead to withdrawal symptoms from the medication itself, including irritability, dysphoria, and insomnia.[36] It is possible that venlafaxine use actually exacerbated cannabis withdrawal symptoms, leading people to use more cannabis than placebo to alleviate their discomfort.[35] Mirtazapine, which increases serotonin and norepinephrine, has also failed to improve abstinence rates in people with cannabis use disorder.[35]

People sometimes use cannabis to cope with their anxiety, and cannabis withdrawal can lead to symptoms of anxiety.[35] Buspirone, a serotonin 1A receptor (5-HT1A) agonist, has shown limited efficacy for treating anxiety in people with cannabis use disorder, though there may be better efficacy in males than in females.[35] Fluoxetine, a selective serotonin reuptake inhibitor, has failed to show efficacy in adolescents with both cannabis use disorder and depression.[35] SSRIs are a class of antidepressant drugs that are also used for the treatment of anxiety disorders, such as generalized anxiety disorder.[37] Vilazodone, which has both SSRI and 5-HT1A agonism properties, also failed to increase abstinence rates in people with cannabis use disorder.[35]

Dronabinol is an agonist that is legally available; in some cases and trials, it reduced symptoms of withdrawal and reduced cannabis use.[4] Entacapone was well-tolerated and decreased cannabis cravings in a trial on a small number of patients.[4] Acetylcysteine (NAC) decreased cannabis use and craving in a trial.[4] Divalproex in a small study was poorly tolerated and did not show a significant reduction in cannabis use among subjects.[4]

Barriers to treatment[edit]

Research that looks at barriers to cannabis treatment frequently cites a lack of interest in treatment, lack of motivation and knowledge of treatment facilities, an overall lack of facilities, costs associated with treatment, difficulty meeting program eligibility criteria and transport difficulties.[dubious ][38][39][40]

Epidemiology[edit]

Cannabis is one of the most widely used drugs in the world. In the United States, between 42%[2] and 49%[41] of people have used cannabis, an estimated 9% of those who use cannabis develop dependence.[18][29] 34.8% of Australians aged 14 years and over have used cannabis one or more times in their life.[42] In the U.S., cannabis is the most commonly identified illicit substance used by people admitted to treatment facilities.[4] Most of these people were referred there by the criminal justice system. 16% of admittees either went on their own, or were referred by family or friends.[43]

In the European Union (data as available in 2018, information for individual countries was collected between 2012 and 2017), 26.3% of adults aged 15–64 used cannabis at least once in their lives, and 7.2% used cannabis in the last year. The highest prevalence of cannabis use among 15 to 64 years old in the EU was reported in France, with 41.4% having used cannabis at least once in their life, and 2.17% used cannabis daily or almost daily. Among young adults (15–34 years old), 14.1% used cannabis in the last year.[44]

Among adolescents (15–16 years old) in a European school based study (ESPAD), 16% of students have used cannabis at least once in their life, and 7% (boys: 8%, girls: 5%) of students had used cannabis in the last 30 days.[45]

Globally, 22.1 million people (0.3% of the worlds population) were estimated to suffer from cannabis dependence.[46]

Research[edit]

Columbia University, in collaboration with the National Institute on Drug Abuse (NIDA), is undertaking a clinical trial that looks at the effects of combined medication on cannabis dependency, to see if lofexidine in combination with dronabinol is superior to placebo in achieving abstinence, reducing cannabis use and reducing withdrawal in cannabis-dependent patients seeking treatment for their marijuana use.[47]

Georgotas & Zeidenberg (1979) conducted an experiment where they gave an average daily dose of 210 mg of tetrahydrocannabinol (THC), an ingredient in cannabis which is responsible for its psychological effects,[48] to a group of volunteers over a 4-week period. After the test ended, the subjects were found to be “irritable, uncooperative, resistant and at times hostile,” and many of the patients experienced insomnia.[49]

A 2014 Cochrane Collaboration review found insufficient data to evaluate the effectiveness of gabapentin and acetylcysteine in the treatment of cannabis dependence and that it warrants further investigation.[29]

See also[edit]

References[edit]

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