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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. |
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