Marijuana is a mixture of leaves and the flowering tops of the Indian hemp
plant Cannabis Sativa, smoked or eaten for its hallucinogenic and
pleasure-giving effects. The psychoactive ingredient of marijuana,
tetrahydrocannabinol (THC), is concentrated in the flowering tops of the
hemp plant; hashish, a drug prepared from the plant resin, has about eight
times more THC than marijuana. Hemp grows throughout temperate regions,
with the more potent varieties produced in dry, hot, upland climates. Expect
for limited medical purposes, cultivating hemp for marijuana is illegal in all
but a few countries.
Marijuana has a lot of slang names including pot, grass, weed, hash,
and about 200 other names. Marijuana is by far the world’s most commonly
used illicit drug and far more dangerous than most users realize. So, there is
just cause for alarm when adolescent marijuana use increases, as it did in the
mid-1990’s, and the age at which youngsters first experiment with pot starts
Many users describe two phases of marijuana intoxication: initial
stimulation, giddiness, and euphoria, followed by sedation and tranquillity.
Mood changes are often accompanied by altered perceptions of time and
space and of one’s bodily dimensions. The thinking processes become
disrupted by fragmentary ideas and memories. Many users report increased
appetite, heightened sensory awareness, and pleasure. Negative effects can
include confusion, acute panic reactions, anxiety attacks, fear, a sense of
helplessness, and loss of self-control.
Like alcohol intoxication, marijuana intoxication impairs reading,
comprehension, memory, speech, problem solving ability, and reaction time.
The effects on the intellect of long-term use are unknown. Consistent
evidence that marijuana induces or causes brain damage does not exist.
Medical research has indicated that the drug is effective in relieving some of
the symptoms of glaucoma and in treating the nausea induced by cancer
chemotherapy and radiation treatments.
The plant Cannabis sativa is the source of both marijuana and hashish.
The leaves, flowers, and twigs of the plant are crushed to produce marijuana:
its concentrated resin is hashish. Both drugs are usually smoked, sometimes
in a pipe or water pipe, but most often in loosely rolled cigarettes known as
“joints.” Some users will slice open and hollow out cigars, replacing the
tobacco with marijuana, to make what are called “blunts.” Joints and blunts
may be laced with other substances, including crack cocaine and the potent
hallucinogen phencyclidine (PCP), substantially altering effects of the drug.
Smoking, however, is not the sole route of administration. Marijuana can be
brewed into tea or mixed in baked products (cookies or brownies). Their
effects are similar: a state of relaxation, accelerated heart rate, perceived
slowing of time, and a sense of heightened hearing, taste, touch, and smell.
These effects can be quite different, however, depending on the amount of
drug consumed and the circumstances under which it is taken. Marijuana and
hashish are not thought to produce psychological dependence except when
taken in large daily doses. The drugs can be dangerous, however, especially
when smoked before driving. Although the chronic effects are not yet certain,
marijuana is probably injurious to the lungs in much the same way that
tobacco is. A source of concern is its regular use by children and teenagers,
because the intoxication markedly alters thinking and interferes with
learning. A consensus exists among physicians and others working with
children and adolescents that use is undesirable and may interfere with
psychological and possibly physical maturation.
Cannabis has been used as a folk remedy for centuries, but it has no
well established medical use today. Experimental work has been done using
its active ingredient, delta-9-tetahydrocannabinol (THC), for treating
alcoholism, seizures, pain, the nausea produced by anti-cancer medications,
and glaucoma. Its usefulness for glaucoma patients more doubtful.
For the highly popular form of marijuana called Sinsemilla (from the
Spanish “without seeds”), made from just the buds and flowering tops of
female plants, THC content averages 7.5 percent and ranges as high as 24
percent. As for hashish, a resin made from flowers of the female plant, THC
levels may be five to ten times higher than crude Marijuana’s.
A mild hallucinogen, marijuana has some of alcohol’s depressant and
disinhibiting properties. User reaction, however, is heavily influenced by
expectations and past experience, and may first-time users feel nothing at all.
Effects of smoking are generally felt within a few minutes and peak in
10 to 30 minutes. They include dry mouth and throat, increased heart rate,
impaired coordination and balance, delayed reaction time, and diminished
short-term memory. Moderate doses tent to induce a sense of well-being and
a dreamy stat of relaxation that encourages fantasies, renders some users
highly suggestible, and distorts perception (making in dangerous to operate
machinery, drive a car or boat, or ride a bicycle). Stronger doses prompt more
intense and often disturbing reactions including paranoia and hallucinations.
Most of marijuana’s short-term effects wear off within two or three
hours. The drug itself, however, tends to linger on. THC is a fat-soluble
substance and will accumulate in fatty tissues in the liver, lungs, testes, and
other organs. Two days after smoking marijuana, one-quarter of the THC
content may still be retained. It will show up in urine tests three days after
use, the traces may be picked up by sensitive blood tests two to four weeks
Chronic marijuana smokers are prey to chest colds, bronchitis,
emphysema, and bronchial asthma. Persistent use will damage lungs and
airways and raise the risk of cancer. There is just as much exposure to
cancer-causing chemicals from smoking one marijuana joint as smoking five
tobacco cigarettes. And there is evidence that marijuana may limit the ability
of the immune system to fight infection and disease.
Marijuana also affects hormones. Regular use can delay the onset of
puberty in young men and reduce sperm production. For women, regular use
may disrupt normal monthly menstrual cycles and inhibit ovulation. When
pregnant women use marijuana, they run the risk of having smaller babies
with lower birth weights, who are more likely than other babies to develop
health problems. Some studies have also found indications of developmental
delays in children exposed to marijuana before birth.
Teens and marijuana. Although dangers exist for marijuana users of all
ages, risk is greatest for the young. For them, the impact of marijuana an
learning is critical, and pot often proves pivotal in the failure to master vital
interpersonal coping skills or make appropriate life-style choices. Thus,
marijuana can inhibit maturity.
Another concern is marijuana’s role as a “gateway drug,” which makes
subsequent use of more potent and disabling substances more likely. The
Center on Addiction and Substance Abuse at Columbia University found
adolescents who smoke pot 85 times more likely to use cocaine than their
non-pot smoking peers. And 60 percent of youngsters who use marijuana
before they turn 15 later go on to use cocaine.
But many teens encounter serious trouble well short of the “gateway.”
Marijuana is, by itself, a high risk substance for adolescents. More than
adults, they are likely to be victims of automobile accidents caused by
marijuana’s impact on judgment and perception. Casual sex, prompted by
compromised judgment or marijuana’s disinhibiting effects, leaves them
vulnerable not only to sexually transmitted diseases (STD’S).
Someone who smokes marijuana regularly may have many of the same
respiratory problems that tobacco smokers have. These individuals may have
daily caught and phlegm, symptoms of chronic bronchitis, and more frequent
chest colds. Continuing to smoke marijuana can lead to abnormal functioning
of lung tissue injured or destroyed by marijuana smoke.
Regardless of the THC content, the amount of tar inhaled by marijuana
smokers and the level of carbon monoxide absorbed are three to five times
greater than among tobacco smokers. This may be due to the marijuana users
inhaling more deeply and holding the smoke in the lungs.
Here is a claim that somebody firmly believes but is proved wrong.
“Critical skills related to attention, memory and learning are impaired among
heavy users of marijuana…” Most people think of marijuana users as
dreamers with the attention spand of a gnat and no memory worth the name.
Wrong. This picture emerging from psychology labs in that there is at most a
kernel of truth in this stereotype, while some studies find no evidence of even
subtle mental impairment in heavy users. And even those that do are open to
a range of interpretations–not necessarily worrying to marijuana users.