||This article needs more medical references for verification or relies too heavily on primary sources. (December 2013)|
|Classification and external resources|
Cannabis dependence or cannabis use disorder is defined in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a condition requiring treatment.
Cannabis is one of the most widely used drugs in the world. In the United States, 49% of people have used cannabis. Although physical addiction has not been proven, 9% of those who use cannabis develop dependence. In the US, as of 2013[update], cannabis is the most commonly identified illicit substance used by people admitted to treatment facilities. Demand for treatment for cannabis use disorder increased internationally between 1995 and 2002.
- 1 Characteristics
- 2 Signs and symptoms
- 3 Risk factors
- 4 Cause
- 5 Diagnosis
- 6 Treatment
- 7 Epidemiology
- 8 Research
- 9 See also
- 10 References
- 11 External links
There is a high prevalence of cannabis use in the US. Among individuals who have ever used cannabis, 9% develop dependence, and 10-20% of those who use cannabis daily develop dependence. Cannabis use is associated with comorbid 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. Many other substances, such as alcohol, are often abused by individuals dependent on cannabis.
Signs and symptoms
Although not medically serious, cannabis withdrawal symptoms can occur in one half of patients in treatment for cannabis use disorders. These symptoms include dysphoric mood (anxiety, irritability, depressed mood, restlessness), disturbed sleep, gastrointestinal symptoms, and decreased appetite. Most symptoms begin during the first week of abstinence and resolve after a few weeks. According to the National Cannabis Prevention and Information Centre in Australia, a sign of cannabis dependence is that the person spends noticeably more time than the average recreational user, recovering from the use of, or obtaining cannabis. For some, using cannabis becomes a large part of the person's life and he or she may miss important activities, preferring to use cannabis instead. People who are cannabis dependent will continue to use it even though they perceive their use as problematic. 
Dependence on cannabis is more common among heavy users. Marijuana use can lead to increased tolerance and, in some users, withdrawal symptoms when trying to stop. Prolonged marijuana 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), and reinforce the body's metabolic systems for synthesizing and eliminating the drug more efficiently.
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.[medical citation needed] The mechanisms that create this tolerance to THC are thought to involve changes in cannabinoid receptor function.[medical citation needed]
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.[medical citation needed]
The main factors in Australia 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 conclude 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.
High risk groups
A number of groups have been identified as being at greater risk of developing cannabis dependence and include adolescent populations, Aboriginal and Torres Strait Islanders (in Australia) and people suffering from mental health conditions.
Young people are at greater risk of developing cannabis dependency 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. In addition 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.
Although rates of adolescent substance use have typically been higher among boys than girls (Bachman et al., 1991; SAMHSA, 2007)[medical citation needed], empirical work points to a narrowing and/or closing of this gender gap where girls may actually be catching up or surpassing their male peers in terms of substance use rates (Donnermeyer, 1992; Johnston, O'Malley, Bachman, Schulenberg, 2006; Wallace et al., 2003)[medical citation needed]. This pattern has been displayed among samples of youth from across a variety of racial and ethnic categories. Recent findings from the Monitoring the Future (MTF) project suggest that although male substance use tends to be greater than that of females at 12th grade, gender differences in earlier years (around 8th grade) are minimal, with some annual drug use rates higher for females than males (Johnston, O'Malley, Bachman, «fe Schulenberg, 2006)[medical citation needed].
Aboriginal and Torres Strait Islanders
Cannabis usage is part of a broader picture of poor health and well-being, stemming from the alienation and dispossession experienced by this population over time. Many of the social determinants of harmful substance use are disproportionately present in Aboriginal and Torres Strait Islander communities.
Cannabis dependency 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.
Cannabis use Disorder is recognized in the fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which added Cannabis withdrawal as a new condition. The average adult who seeks treatment has consumed cannabis for over 10 years almost daily and has actively attempted to quit six or more times.
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. 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.
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. Screening and brief intervention sessions can be given in a variety of settings, particularly at doctor's surgeries, which is of importance as most cannabis users seeking help will do so from their general practitioner rather than a drug treatment service agency.
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. 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.
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.
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.
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. Dronabinol is an agonist that is legally available; in some cases and trials, it reduced symptoms of withdrawal and reduced cannabis use. Entacapone was well-tolerated and decreased cannabis cravings in a trial on a small number of patients. Acetylcysteine (NAC) decreased cannabis use and craving in a trial. Atomoxetine in a small study showed no significant change in cannabis use, and most patients experienced adverse events. Buspirone shows promise as a treatment for dependence; trials show it reducing cravings, irritability and depression. Divalproex in a small study was poorly tolerated and did not show a significant reduction in cannabis use among subjects.
Barriers to treatment
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. A technical report compiled by Australia's National Cannabis Centre.
Cannabis is the most commonly used illegal drug worldwide. 34.8% of Australians aged 14 years and over have used cannabis one or more times in their life. In the United States, 42% have used cannabis. In the U.S., cannabis is the most commonly identified illicit substance used by people admitted to treatment facilities. 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. 
Columbia University, in collaboration with the National Institute on Drug Abuse (NIDA), is undertaking a clinical trial that looks at the effects of combined pharmacotherapy on cannabis dependency, to see if Lofexidine in combination with Marinol is superior to placebo in achieving abstinence, reducing cannabis use and reducing withdrawal in cannabis-dependent patients seeking treatment for their marijuana use. Men and women between the ages of 18-60 who met DSM-IV criteria for current marijuana dependence were enrolled in a 12-week trial that started in January 2010.
Georgotas & Zeidenberg (1979) conducted an experiment where they gave an average daily dose of 210 mg of tetrahydrocannabinol (THC), the ingredient in cannabis which is responsible for its psychological effects, to a group of volunteers over a 4 week period. After test ended, the subjects were found to be "irritable, uncooperative, resistant and at times hostile," and many of the patients experienced insomnia. These effects were likely due to withdrawal from the drug and lasted about 3 weeks after the experiment.
- Gordon AJ, Conley JW, Gordon JM (December 2013). "Medical consequences of marijuana use: a review of current literature". Curr Psychiatry Rep (Review) 15 (12): 419. doi:10.1007/s11920-013-0419-7. PMID 24234874.
- Budney, AJ; Roffman, R; Stephens, RS; Walker, D (Dec 2007). "Marijuana dependence and its treatment.". Addiction science & clinical practice 4 (1): 4–16. doi:10.1151/ascp07414. PMC 2797098. PMID 18292704.
- Borgelt LM, Franson KL, Nussbaum AM, Wang GS (February 2013). "The pharmacologic and clinical effects of medical cannabis". Pharmacotherapy (Review) 33 (2): 195–209. doi:10.1002/phar.1187. PMID 23386598.
- Substance Abuse and Mental Health Services Administration, Office of Applied Studies. (2003). Emergency department trends from the drug abuse warning network, final estimates 1995–2002, DAWN Series: D-24, DHHS Publication No. (SMA) 03-3780.
- Danovitch I, Gorelick DA (June 2012). "State of the art treatments for cannabis dependence". Psychiatr. Clin. North Am. (Review) 35 (2): 309–26. doi:10.1016/j.psc.2012.03.003. PMC 3371269. PMID 22640758.
- Dervaux, Alain (12/12). "Cannabis: Use and dependence". La Presse Médicale. Check date values in:
- "Is marijuana addictive?". National Cannabis Prevention and Information. Retrieved 17 April 2015.
- Sewell RA, Poling J, Sofuoglu M (2009). "The effect of cannabis compared with alcohol on driving". Am J Addict (Review) 18 (3): 185–93. doi:10.1080/10550490902786934. PMC 2722956. PMID 19340636.
- J.E. Joy, S. J. Watson, Jr., and J.A. Benson, Jr, (1999). Marijuana and Medicine: Assessing The Science Base. Washington, D.C.: National Academy of Sciences Press. ISBN 0-585-05800-8.
- Copeland, J, Gerber, S, Swift, W. Evidence-based answers to cannabis questions a review of the literatureNational Drug and Alcohol Research Centre University of New South Wales A report prepared for the Australian National Council on Drugs, December 2004
- McLaren, J, Mattick, R P., Cannabis in Australia Use, supply, harms, and responses Monograph series No. 57 Report prepared for: Drug Strategy Branch Australian Government Department of Health and Ageing. National Drug and Alcohol Research Centre University of New South Wales, Australia.
- Ministerial Council on Drug Strategy (2003) Background paper: National Drug Strategy. Aboriginal and Torres Strait Islander peoples complementary action plan 2003-2006, Commonwealth of Australia, Canberra.
- Spooner, C. and Hetherington, K. (2005) Social determinants of drug use. NDARC technical report No. 228 Sydney, National Drug and Alcohol Research Centre, University of New South Wales
- Coffey1, Carlin2, Lynskey3, Li4, Patton5, Carolyn1, John B.2, Michael3, Ning4, George C.5 (1/4/03). "Adolescent precursors of cannabis dependence: Findings from the Victorian Adolescent Health Cohort Study". The British Journal of Psychiatry 182: 330–336. doi:10.1192/bjp.182.4.330. Retrieved 17/4/15. Check date values in:
- "Proposed Revision | APA DSM-5". Dsm5.org. Retrieved 2011-04-20.
- "Highlights of Changes from DSM-IV-TR to DSM-5" (PDF). American Psychiatric Association. 17 May 2013. Retrieved 12 December 2013.
- Budney, Alan J.; Roffman, Roger; Stephens, Robert S.; Walker, Denise (2007-12). "Marijuana Dependence and Its Treatment". Addiction Science & Clinical Practice 4 (1): 4–16. doi:10.1151/ascp07414. ISSN 1940-0632. PMC 2797098. PMID 18292704. Retrieved 2015-04-16. Check date values in:
- Marshall, K; Gowing, L; Ali, R; Le Foll, B (17 December 2014). "Pharmacotherapies for cannabis dependence.". The Cochrane database of systematic reviews 12: CD008940. doi:10.1002/14651858.CD008940.pub2. PMID 25515775.
- Copeland J, Swift W (April 2009). "Cannabis use disorder: epidemiology and management". Int Rev Psychiatry (Review) 21 (2): 96–103. doi:10.1080/09540260902782745. PMID 19367503.
- EMCDDA (2007). Annual report 2007: The state of the drugs problem in Europe. Luxembourg: Office for Official Publications of the European Communities
- Degenhardt, L., Hall, W. and Lynskey, M. (2000a) Cannabis use and mental health among Australian adults: Findings from the National Survey of Mental Health and Well-being. NDARC Technical Report No. 98 Sydney, National Drug and Alcohol Research Centre, University of New South Wales.
- Clinical Textbook of Addictive Disorders, Marijuana, David McDowell, page 169, Published by Guilford Press, 2005 ISBN 1-59385-174-X.
- "With Support From Collaborative, Primary Care Practices Identify and Address Behavioral Health Issues, Reducing Binge Drinking, Marijuana Use, and Depression Symptoms". Agency for Healthcare Research and Quality. 2013-05-08. Retrieved 2013-05-10.
- Treloar, C.; Holt, M. (2006). "Deficit models and divergent philosophies: Service providers' perspectives on barriers and incentives to drug treatment". Drugs: Education prevention and policy 13 (4): 367–382. doi:10.1080/09687630600761444.
- Treloar, C., Abelson, J., Cao, W., Brener, L., Kippax, S., Schultz, L., Schultz, M., & Bath, N. (2004). Barriers and incentives to treatment for illicit drug users(Monograph Series 53). Canberra: Department of Health and Ageing, National Drug Strategy.
- Gates, P., Taplin, S., Copeland, J., swift, W., Martin G. (2008) Barriers and Facilitators to Cannabis TreatmentNational Cannabis Prevention and Information Centre, University of New South Wales, Sydney
- "Drug Info". Australian Drug Foundation.
- "Treatment Episode Data Set (TEDS)2001 - 2011. National Admissions to Substance Abuse Treatment Services" (PDF). samhsa.gov. Substance Abuse and Mental Health Services Administration. Retrieved 17 April 2015.
- "US National Institute of Health". Clinicaltrials.gov. Retrieved 2011-04-20.
- Bradford, Alina (2015). "Live Science". What is THC (tetrahydrocannabinol)?. Retrieved 17/4/15. Check date values in:
- Johns, Andrew (1/2/01). "Psychiatric effects of cannabis". The British Journal of Psychiatry 178: 116–122. doi:10.1192/bjp.178.2.116. Retrieved 17/4/15. Check date values in:
Walls, M. L. (2008). MARIJUANA AND ALCOHOL USE DURING EARLY ADOLESCENCE: GENDER DIFFERENCES AMONG AMERICAN INDIAN/FIRST NATIONS YOUTH. Journal of Drug Issues, 38(4), 1139-1160. Retrieved from http://search.proquest.com/docview/208836781?accountid=14541