EPIDEMIOLOGICAL surveys indicate that the large majority of people who try marijuana do not become long-term frequent users. A study of adults in their thirties, who were first surveyed in high school, found a high “discontinuation rate” for marijuana. Of those who had tried marijuana, 75 percent had not used it in the past year and 85 percent had not used it in the past month. In 1994, among Americans age twelve years and older, 31 percent had used marijuana sometime in their lives. Eleven percent had used it in the past year and 2.5 percent had used it an average of once a week or more.
Only 0.8 percent of Americans currently smoke marijuana on a daily or near daily basis. Some people smoke marijuana regularly for years without experiencing adverse physical, psychological, or social consequences. At some point, many high-dose frequent users decide to reduce their intake or cease using marijuana altogether.
For most, this appears to be a relatively simple process. For example, one study looked at twenty-eight and twenty-nine-year-old men who had been daily marijuana users sometime during the previous decade. At the time of the survey, 85 percent were no longer using marijuana on a daily basis, although most continued to use it occasionally. Some people who use marijuana heavily and frequently find the process of reduction or cessation more difficult, and some seek assistance from drug treatment providers.
There has been a recent increase in the number of people entering treatment programs with a primary diagnosis of marijuana dependence. However, most marijuana users enrolled in drug treatment programs are poly-drug abusers who also report problems with alcohol, cocaine, amphetamine, tranquilizers, or heroin.
Studies conducted over several decades in a variety of settings have found that when high-dose marijuana users stop using the drug, withdrawal symptoms rarely occur. When withdrawal symptoms do occur, they tend to be “mild and transitory.” In a study conducted at the Federal Narcotics Hospital in Lexington, Kentucky in the 1960s, ten men were kept constantly “high” with at least one marijuana cigarette during every waking hour for thirty days.
Upon the abrupt cessation of smoking, no withdrawal symptoms were evident. In another study, huge oral doses of THC were given daily to people for thirty days. When drug administration was ended, subjects had modest complaints of rest lenses, sleep disturbance, nausea, decreased, appetite, and sweating. In a recent survey, 16 percent of high-dose marijuana users reported some withdrawal symptoms upon quitting, most commonly nervousness and sleep disturbance.
In some animal studies, high doses of THC given intravenously, then stopped abruptly, produce behavioral alteration, including increases in aggressiveness and moto activity. However, no matter how much THC is administered to animals, when it is stopped, animals do not self-administer THC.
In a recent study, researchers precipitated more pronounced physical withdrawal symptoms in mice. They did this by infusing the mice with large doses of THC continuously for four days, and then administering a cannabinoid “blocker drug” which immediately strips THC from receptors.
This NIDA-funded rodent study of “precipitated withdrawal” is now cited as evidence that marijuana causes physical dependence. In fact, it has no relevance to human marijuana users who, upon ceasing use, always experience a gradual separation of THC from receptors.
Although people develop dependence on marijuana, a 1991 U.S. Department of Health and Human Services report to Congress states that: Given the large population of marijuana users and the infrequent reports of medical problems from stopping use, tolderance and dependence are not major issues at present.
Recently, pharmacologists Jack Henning field and Neal Benowitz independently ranked the dependencec potential of sic psychoactive drugs: caffeine, nicotine, alcohol, heroin, cocaine, and marijuana. Both ranked caffeine and marijuana as the two least addictive. Henning field gave the two drugs identical scores and Benowitz ranked marijuana as slightly less addicting than caffeine.
Nonetheless, the number of people diagnosed as marijuana dependent and the number of marijuana users enrolled in drop treatment programs have been rising steadily. Using the American Psychiatric Association’s (APA) list of criteria for drug dependence, researchers evaluating marijuana users in community samples have diagnosed as many as 25 percent as marijuana dependent. Drug treatment providers Norman Miller and Mark Gold claim that because the symptoms of marijuana addiction are “often subtle and difficult to identify,” marijuana users should be diagnosed as dependent even when they do *not *meet APA’s standard. Gold maintains that “it is important to treat all cases of marijuana use as potentially addictive.” Most of the recent articles and boos claiming a growing problem of marijuana dependence have been written by drug treatment providers.
This group has also benefited enormously from the expansion of treatment services to marijuana users, many of whom are pressured or forced into treatment by parents or other relatives, the courts, or employers. Most workers who test positive in workplace drug testing programs are marijuana users, and many use marijuana only occasionally. Employers typically require workers to participate in drug treatment as a condition of continued employment. Drug treatment programs diagnose marijuana users as “marijuana dependent” even when they do not meet official criteria of drug dependence.