Addiction is generally defined as a physical or psychological dependence on a substance, especially alcohol or other drugs, with use of increasing amounts. For the sake of clarification, physical addiction is covered separately from psychological dependence on this website. (See also the section titled Dependence.) Scientific research on cannabinoid compounds has not demonstrated a strong association with biochemical addiction. In their exhaustive quest for evidence of addiction, federally funded researchers have resorted to relying on questionable data, such as the withdrawal symptoms reported by children who were referred to social service and criminal justice agencies. These researchers may argue that the court-ordered testimony of troubled youths “proves” that marijuana is addictive; however, such questionable data is not scientific evidence of chemical addiction. In another case, an addictions researcher reported on his experiment in which rats displayed withdrawal symptoms upon a sudden discontinuation of THC. Critics point out that the reported withdrawal effects were created with very high doses of THC, and by the introduction of a second drug, a THC-blocking agent used to trigger the withdrawal symptoms. Withdrawal symptoms are not found in rats without using a THC-blocking agent, and even among troubled youths, withdrawal symptoms are relatively mild and of short duration. , 
Dopamine, a neurochemical produced in the central cortex of the brain, is thought to provide the brain’s “reward system.” Interference with dopamine production is considered a major symptom of biochemical addiction. While two studies alleged a minor link between THC and dopamine production in the brains of rats, these were refuted by several subsequent studies showing that cannabis does not radically affect dopamine levels., ,  In assessing the importance of a possible link between cannabis use and dopamine levels, it should be noted that dopamine activity has also been detected in the brains of video game players who were paid money every time they reached a new level of the game. Clearly, minor evidence of dopamine activity is not the sloe indicator of addiction. If it were, than all pleasurable activities would be defined as addictive. Moreover, the scientific evidence that cannabis use produces any amount of increased dopamine activity remains entirely inconclusive. Assessing the scientific literature on marijuana’s addictive potential for the Criminal Justice Commission of Australia, Peter Nelson reported, “… involvement with the ventromedial striatum suggests connections to dopamine circuits. However, the expected reinforcing properties usually associated with these dopamine pathways are difficult to demonstrate in the case of THC.”
Cannabinoids bond to anandamide nerve receptors that are primarily concentrated in the frontal lobes of the brain,,  rather than in the central cortex where dopamine is produced. THC is mild, with effects resembling those of caffeine or chocolate rather than classic addictive drugs such as alcohol, amphetamines, cocaine, opiates, and nicotine. In fact, a 1996 report from Daniele Piomelli of the Neurosciences Institute in San Diego indicated that chocolate contains three compounds that are chemically similar to cannabinoids. Studies involving rats showed that cannabinoid chemicals found in chocolate amplify the effect of natural cannabinoids found in the brain. The article published in Nature concluded that these compounds may, “participate in the subjective feelings of eating chocolate.” In the April 1999 issue of Nature Neuroscience, Piomelli and colleagues at the University of California, Irvine reported that anandamide acts as an inhibitor of dopamine neurons. Far from triggering chemical addiction in the brain, THC, the natural anandamide analogue, may actually help to balance erratic dopamine levels.
The common scientific criteria for determining the addictive quality of a drug are examples of animal studies in which subjects self-administer an addictive substance. When given the choice between food and narcotics, for example, animals commonly self-administer the drug to the exclusion of all other activity, often starving themselves to death. Unlike heroin, cocaine, and other substances of abuse, there are no clinical studies showing animals self-administering cannabinoid compounds. In 1993, the Congressional Office of Technology Assessment reached this conclusion:
While marijuana produces a feeling of euphoria in humans, in general, animals will not self-administer THC in controlled studies. Also, cannabinoids generally do not lower the threshold needed to get animals to self-stimulate the brain reward system as do other drugs of abuse.
Clinical studies indicate a very low potential for addiction to cannabinoid drugs. In addition, there is no real-world evidence suggesting that THC is chemically addictive. Epidemiological studies show that the large majority of people who try marijuana do not continue to use it on a regular basis. Moreover, the majority of people who ever use cannabis stop using it entirely before the age of thirty. Of an estimated 65 million “experimenters,” only about 0.8% of Americans use cannabis on a daily basis. The fact that millions of Americans have stopped using marijuana voluntarily and without difficulty is strong epidemiological evidence that cannabis is not chemically addictive.
Despite federally funded sociological and scientific findings that marijuana produces only mild dependence in some heavy users,,  the federal government has officially classified cannabis as a Schedule I substance that has “a high potential for abuse.” Recent research determining that cannabinoids are not chemically addictive and do not have a high potential for abuse forms the basis of a petition filed with the Drug Enforcement Administration. That petition prompted the federal drug agency to enter into a legally binding review of the existing evidence by the US Department of Health and Human Services in 1997. Two years later, investigative authors of the 1999 Institute of Medicine report determined that, “… marijuana was not particularly addictive.” Yet cannabis is still classified as having, “no medical value and a high potential for abuse.” In 1999, Dr. Podrebarac wrote to the White House Office of National Drug Control Policy: “The recently released Institute of Medicine (IOM) study on the medical use of marijuana clearly supports rescheduling it for medical use.” The US Drug Czar’s office refused to comment on the rescheduling issue.
Cannabis authority Tod Mikuriya wrote extensively on the value of cannabis in treating addiction. Consider the following excerpt:
“In 1839, William B. O’Shaughnessy visited cannabis buyers’ centers in India and mingled with the “dissolute and depraved” to learn about the preparations of this social drug for clinical medical trials and found it to be useful in the treatment of tetanus and seizures.
In 1843, Clendinning utilized cannabis substitution for the treatment of alcoholism and opium addiction. Potter recommended full-dose Squibb cannabis extract for withdrawal from opium addiction.
In 1894, the Indian Hemp Drugs Commission Report recognized the comparative safety of cannabis in its unsurpassed ethnographic studies within different cultures with a concern that if prohibited it would cause the use of more dangerous drugs.
McMeens, citing Fronmueller in 1860, found that the use of cannabis in place of, or combined with, opiates reduced harm from increased dose, tolerance, dependence, and side effects of opiates. In 1897, cannabis was confirmed as useful in the treatment of delirium tremens and as an alternative to opium for analgesia. Dutt independently described the comparative safety of cannabis in Materia medica of the Hindus. Yeo and colleagues warned about addiction to morphine in the treatment of neuralgia and suggested cannabis as an alternative.”
The connection between dependency on drugs and mood disorders may be caused by unsuccessful attempts to self-medicate uncomfortable feelings with the “cure,” causing more harm and aggravation of the underlying condition. Moreau described cannabis as being useful in the treatment of depression in 1845. Throughout both the late nineteenth and early twentieth century, the drug was listed in medical texts and pharmaceutical catalogues for treatment of melancholia or mania.
Notwithstanding some polysubstance abusers who maladaptively combine cannabis with other psychoactives, there appears to be a significant number of persons who have learned that cannabis can totally substitute for other psychoactive drugs.
Following the therapeutic paths of Clendinning, throughout the nineteenth and twentieth century, cannabis was found useful in the treatment of opiate and sedative abuse. Brunton described the use of cannabis for the treatment of opiate dependence or as a substitute when opiates were not tolerated. Shoemaker found cannabis to be used for the cure of opium or chloral habits. Birch advocated for the use of Indian hemp in the treatment of chronic chloral and opium poisoning. Mattison, an early addcition specialist, recommended cannabis as a substitute for morphine and cautioned his fellow physicians about hypodermic use of the opiate.
Alcohol abuse, stimulant, sedative, and opioid abuse and dependence are conditions potentially treatable with cannabis substitution. All of these conditions involve management of mood and emotional reactivity. Although there have been numerous synthetic homologues developed, short-acting psychotropic drugs continue to have high potential for dependency and abuse. The quality of immediacy for mood management would appear to be inseparable from abuse potential but cannabis appears to be the exception because of lesser or milder withdrawal symptoms.
California cannabis center members and patients in my private practice independently rediscovered and confirmed that cannabis is a safer substitute for many prescribed and most nonmedical psychoactive drugs in the control of depression, anger, and anxiety. Cannabis substitution may be a gateway drug back to sobriety and dealing with the underlying psychopathalogic etiologies.
Related sections: Cerebral Effects, Dependence, Tolerance, Treating Addiction
 Taber’s Cyclopedic Medical Dictionary. Philadelphia: F.A. Davis Company, 1987
 “US Study: Marijuana is addictive.” Reuters, March 31, 1998
 “New Scientist special report on marijuana.” New Scientist, February 21, 1998
 “US Study: Marijuana is addictive.” op. cit.
 Institute of Medicine, Marijuana and Medicine: Assessing the Science Base. Washington, DC: National Academy Press, 1999
 “Similar effects found in pot, harder drugs.” Maugh, Los Angeles Times, June 27, 1997
 Castaneda, et al., “THC does not affect striatal dopamine release: microdialysis in freely moving rats.” 1991
 Gifford, Gardner, and Ashby, “The effects of intravenous administration of delta-9-tetrahydrocannabinol on the activity of the A 10 dopamine neurons recorded in vivo in anesthetized rats.” Neuropsychopharmacology Vol. 36, No. 2, pp. 96-99, 1997
 “The July 1995 Gettman/High Times petition to repeal marijuana prohibition: An extensive review of relevant legal and scientific findings.” Source: www.hightimes.com/ht/new/petition/jgpetition/index.html
 "Researchers watch dopamine changes in brain of video game players.” Associated Press, May 21, 1998
 Nelson, “A Critical Review of the Research Literature Concerning Some Biological and Psychological Effects of Cannabis.” Advisory Committee on Illicit Drugs, Cannabis and the Law in Queensland, pp. 113-152, Source: Schaffer Library of Drug Policy, www.druglibrary.org
 Piomelli, “Functional role of high-affinity anamdamide transport, as revealed by selective inhibition.” Science, Vol. 277, No. 5329, p. 1094(4), August 22, 1997
 Gettman, op. cit. See also: Gettman, “Marijuana and the human brain.” High Times, March 1995
 “Chocolate and Cannabinol.” The Washington Post, August 26, 1996
 Stein, “Bits and Pieces.” Geriatric Psychiatry News, Issue 3, No. 7, June/July 1999
 U.S. Congress OTA, 1993
 Grinspoon, Bakalar, Zimmer, and Morgan, “Marijuana Addiction.” Science, Vol. 277, p. 749, August 8, 1997
 Annas, “Reefer Madness—The federal response to California’s medical-marijuana law.” The New England Journal of Medicine, Vol. 337, No. 6, August 7, 1997
 Zimmer and Morgan, Marijuana Myths: Marijuana Facts. New York: The Lindesmith Center, 1997
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[21 Institute of Medicine, Marijuana and Medicine: Assessing the Science Base. Washington, DC: National Academy Press, 1999
 “DEA refers marijuana rescheduling petition to HHS.” The Law Offices of Michael Kennedy, NY, 1998
 Official report backs medical use of marijuana.” Reuters, March 17, 1999
 Mikuriya, “Dependency and Cannabis.” Chapter 20, p. 225-227