Marijuana is the single most-used illicit drug in the
United States. Despite being illegal, marijuana use rivals the
popularity of browsing the Internet.
In 1998, more than 76.5 million Americans logged onto the
Internet, according to Computer
Industry Almanac. In that same year, more than 71 million
Americans over the age of 12 admitted that they have used
marijuana at least once in their lifetime.
Photo courtesy Marijuana.com
Marijuana comes from the Cannabis sativa
plant and is the most commonly used illicit drug in the
Marijuana is the dried buds and leaves of the Cannabis
sativa plant. This plant contains more than 400 chemicals,
including delta-9-tetrahydrocannabinol (THC), the
plant's main psychoactive chemical. THC is known to affect our
short-term memory. Additionally, marijuana affects motor
coordination, increases your heart rate
and raises levels of anxiety. Studies also show that marijuana
chemicals typically associated with cigarettes.
Although banned by the U.S. federal government in 1937,
there were 11 million current users of the drug in 1999,
according to the Substance
Abuse & Mental Health Services Administration,
"current" meaning that they had used the drug within 30 days
of the survey. In this edition of HowStuffWorks,
you will learn about marijuana, why this drug is so popular
and what effects it has on your mind and body.
Cultivation of the Cannabis
sativa plant dates back thousands of years. The first
written account of cannabis cultivation is found in Chinese
records dating from 28 B.C., according to the book "Buzzed:
The Straight Facts About the Most Used and Abused Drugs from
Alcohol to Ecstasy." However, the book's authors point out
that the plant was likely cultivated long before then. They
recount the discovery of a nearly 3,000-year-old Egyptian mummy
containing traces of THC, the main psychoactive chemical in
marijuana. It could be that cannabis was used as some type of
medicinal herb during this time.
Photo courtesy Marijuana.com
The recognizable marijuana leaf with five to
seven leaflets attached at a center
Cannabis sativa is
perhaps the most recognizable plant in the world. Pictures of
the ubiquitous green cannabis leaf show up in the news media,
textbooks and drug-prevention literature, and the leaf's shape
is made into jewelry, put on bumper stickers and clothing and
spray-painted on walls. The leaves are arranged palmately,
radiating from a common center like the fingers of a hand
spreading apart. Although most people know what the cannabis
plant looks like, they may know very little about its
sativa plant has many uses. Its stiff, fibrous stalk can
be used to make lots of products, from food to
ship sails. The stalk is comprised of two parts -- the
hurd and the bast. The bast provides
fibers that can be woven into many fabrics. These fibers
(also called hemp) are woven to create canvas,
which have been used to make ship sails for centuries.
The hurd provides pulp to make paper, oil to make
paints and varnishes, and seed for food. Cannabis plants
produce a high-protein, high-carbohydrate seed that is
used in granola and cereals. Hemp oil and seed contain
only trace amounts of psychoactive chemicals. Click
here to learn more about hemp and its uses.
Owning hemp products, such as hemp rope or a hemp
shirt, is legal. However, it is illegal to grow or
possess marijuana in plant or drug form in the United
States. Possession of the cannabis plant or marijuana is
punishable by fines and possible jail sentences.
Cannabis sativa is believed to be a native plant of India,
where it possibly originated in a region just north of the
Himalayan mountains. It is a herbaceous annual that can grow
to a height of between 13 and 18 feet (4 to 5.4 meters). The
plant has flowers that bloom from late-summer to mid-fall.
Cannabis plants usually have one of two types of flowers, male
or female, and some plants have both. Male flowers grow in
elongated clusters along the leaves and turn yellow and die
after blossoming. Female flowers grow in spike-like clusters
and remain dark green for a month after blossoming, until the
seed ripens. Hashish, which is more powerful than
marijuana, is made from the resin of the cannabis flowers.
Marijuana plants contain more than 400 chemicals, 60 of
which fit into a category called cannabinoids,
according to the National
Institutes of Health. THC is just one of these
cannabinoids, but it is the chemical most often associated
with the effects that marijuana has on the brain.
Cannabis plants also contain choline, eugenol, guaicacol and
piperidine. The concentration of THC and other cannabinoids
varies depending on growing conditions, plant genetics and
processing after harvest. You'll learn more about the potency
of THC and the toxicity of marijuana later.
Entering the Body
Every time a user smokes a
marijuana cigarette or ingests marijuana in some other form,
THC and other chemicals enter the user's body. The chemicals
make their way through the bloodstream
to the brain and
then to the rest of the body. The most powerful chemical in
marijuana is THC (delta-9-tetrahydrocannabinol), which is
primarily responsible for the "high" associated with the drug.
The most common way of using marijuana is smoking. Smoking
is also the most expedient way to get the THC and other
chemicals into the bloodstream. When the smoke from marijuana
is inhaled, the THC goes directly to the lungs. Your
lungs are lined with millions of alveoli, the tiny air
sacs where gas exchange occurs. These alveoli have an enormous
surface area -- 90 times greater than that of your skin -- so
they make it easy for THC and other compounds to enter the
body. The smoke is absorbed by the lungs just seconds after
After inhaling marijuana smoke, its chemicals
are distributed throughout the
You can also eat marijuana. In this case, the marijuana
enters the stomach and the blood
absorbs it there. The blood then carries it to the liver and
the rest of the body. The stomach absorbs THC more slowly than
the lungs. When marijuana is eaten, the levels of THC in the
body are lower, but the effects last longer.
Marijuana and the Brain
THC is a very potent
chemical compared to other psychoactive drugs. An intravenous
(IV) dose of only one milligram (mg) can produce serious
mental and psychological effects. Once in your bloodstream,
THC typically reaches the brain within seconds after it is
inhaled and begins to go to work.
Marijuana users often describe the experience of smoking
marijuana as initially relaxing and mellow, creating a feeling
of haziness and light-headedness. The user's eyes may dilate,
causing colors to appear more intense, and other senses may be
enhanced. Later, feelings of a paranoia and panic may be felt
by the user. The interaction of the THC with the brain is
what causes these feelings. To understand how THC acts on the
brain, you need to know about the parts of the brain that are
affected by the chemical. Here are the basics:
- Neurons are the cells that
process information in the brain. Chemicals called
neurotransmitters allow neurons to communicate with
- Neurotransmitters fill the gap, or synapse,
between two neurons and bind to protein receptors,
which enable various functions and allow the brain and body
to be turned on and off.
- Some neurons have thousands of receptors that are
specific to particular neurotransmitters.
- Foreign chemicals, like THC, can mimic or block actions
of neurotransmitters and interfere with normal functions.
In your brain, there are groups of cannabinoid receptors
concentrated in several different places. These cannabinoid
receptors have an effect on several mental and physical
- Short-term memory
- Problem solving
Cannabinoid receptors are activated by a neurotransmitter
called anandamide. Anandamide belongs to a group of
chemicals called cannabinoids. THC is also a cannabinoid
chemical. THC mimics the actions of anandamide, meaning that
THC binds with cannabinoid receptors and activates
neurons, which causes adverse effects on the mind and body.
High concentrations of cannabinoid receptors exist in the
hippocampus, cerebellum and basal
ganglia. The hippocampus is located within the temporal
lobe and is important for short-term memory. When the THC
binds with the cannabinoid receptors inside the hippocampus,
it interferes with the recollection of recent events. THC also
affects coordination, which is controlled by the cerebellum.
The basal ganglia controls unconscious muscle movements, which
is another reason why motor coordination is impaired when
under the influence of marijuana.
Other Physiological Effects
In addition to
the brain, marijuana affects many other parts of the body.
Marijuana is filled with hundreds of chemicals, and when it is
burned, hundreds of additional compounds are produced. When
marijuana is inhaled or ingested in some other form, several
short-term effects occur. Some of these effects are:
- Problems with memory and learning
- Distorted perception
- Difficulty with thinking and problem solving
- Loss of coordination
- Increased heart rate
- Anxiety, paranoia and panic attacks
The initial effects created by the THC wear off within an
hour or two after using marijuana, but the chemicals stay in
your body for much longer. The terminal half-life of
THC is from about 20 hours to 10 days, depending on the amount
and potency of the marijuana used. This means that if you take
one milligram of THC that has a half-life of 20 hours, you
will still have 0.031 mg of THC in your body more than four
days later. The longer the half-life, the longer the THC
lingers in your body.
phenomenon associated with marijuana use is the
increased hunger that users feel, often called the
"munchies." Research shows that marijuana increases food
enjoyment and the number of times a person eats each
day, according to the National
Institutes of Health.
Until recently, the munchies were a relative mystery.
However, a recent study by Italian scientists may
explain what happens to increase appetite in marijuana
users. Molecules called endocannabinoids bind
with receptors in the brain and activate hunger.
This research indicates that endocannabinoids in the
hypothalamus of the brain activate cannabinoid
receptors that are responsible for maintaining food
intake. The results of the study were published in an
April 2001 issue of the scientific journal Nature.
Research shows that marijuana is not physically addictive,
but it can be psychologically addictive. It's not considered
physically addictive because users show few or no withdrawal
symptoms during cessation. Psychological dependence usually
develops because a person's mind craves the high that it gets
when using the drug.
Beyond the psychological effects that marijuana has,
marijuana smokers are susceptible to the same health problems
as tobacco smokers, such as bronchitis, emphysema and
bronchial asthma. Other effects include dry-mouth, red eyes,
impaired motor skills and impaired concentration. Long-term
use of the drug can increase the risk of damaging the lungs
system, according to the U.S. Drug Enforcement Agency
(DEA). It has also been linked to heart
Although marijuana is known to have negative effects on the
human body, there is a raging debate over the use of marijuana
as a medical treatment. Some say that marijuana should be
legalized for medical use because it has been known to
suppress nausea, relieve eye pressure in glaucoma patients,
spasms, stimulate appetite, stop convulsions and eliminate menstrual
pain. Others claim that marijuana's negative effects outweigh
its benefits. There are currently nine U.S. states that allow
for the use of marijuana for medical purposes: Alaska,
Arizona, California, Colorado, Hawaii, Maine, Nevada, Oregon
Whether marijuana is more potent
today than it was in 30 or 40 years ago is at the center of
much debate. The U.S. federal government has released
information saying that the levels of potency have risen
anywhere from 10 to 25 times since the 1960s. Is this a myth
question that marijuana, today, is more potent than the
marijuana in the 1960s. However, if you were to look at the
average marijuana potency which is about 3.5 percent, it's
been relatively stable for the last 20 years. Having said
that, it's very important that what we have now is a wider
range of potencies available than we had in the 1970s, in
particular," Director of the National Institute on Drug Abuse
Alan Leshner said in 1999 while testifying in front of
the U.S. House Subcommittee on Crime.
MarijuanaAn estimated 20
million workers are drug-tested annually in the United
States at a cost of more than $1 billion. The body
metabolizes THC into about five metabolites
before passing it into the body's urine, so drug tests
are designed to detect the metabolites instead of THC.
Detectable amounts of these metabolites remain in the
system for several days to several weeks following
marijuana use, depending on the level of use.
The most common test for detecting marijuana or any
drug is the immuno-assay. In this test, the urine
is mixed with a solution containing an antibody specific
to certain metabolites. The antibody is usually tagged
with a fluorescent dye or radioactive substance. The
amount of fluorescent light or radioactivity is measured
to determine the concentration of metabolites in the
Gas chromatography/mass spectrometry may also
be used to test for THC metabolites.
Those who support the legalization of marijuana say that
the data is skewed because testing was only performed on
marijuana of specific geographic origins in the 1960s and
1970s, and therefore is not representative of marijuana
potency overall. Officials obtained the samples from a type of
Mexican marijuana that is known to contain low levels of THC
-- 0.4 to 1 percent. When these levels are compared to other
types of marijuana, it looks as if potency levels have risen
in the last 30 years.
Typical THC levels, which determines potency, range from
0.3 to 4 percent. However, some specially grown plants can
contain THC levels as high as 15 percent. Several factors are
involved in determining the potency of a marijuana plant,
- Growing climate and conditions
- Plant genetics
- Harvesting and processing
The time at which the plant is harvested affects the level
of THC. Additionally, female varieties have higher levels of
THC than male varieties. As a cannabis plant matures, its
chemical composition changes. During early development,
cannabidiolic acid is the most prevalent chemical.
Later, cannabidiolic acid is converted to cannabidiol,
which is later converted to THC when the plant reaches its
To determine the average potency levels of marijuana,
researchers need to examine a cross section of cannabis
plants, which wasn't done in the 1960s and 1970s. This makes
it difficult to make accurate comparisons between the THC
levels of that time period and the THC levels of today.
Marijuana is readily available in
almost every corner of the United States, according to the Department
of Justice. It's found growing in homes, on farms, in the
suburbs and in the city. Cannabis is frequently found growing
on public land, often in remote locations to prevent
observation and identification of the growers. In 1999, the
U.S. Forest Service seized almost 1 million pounds (453,592
kg) of cannabis plants and processed marijuana in 35 states.
Marijuana is also smuggled into the United States from Mexico,
Cambodia and Thailand, among other countries.
There is a growing trend toward indoor cultivation of
marijuana in the United States because of the DEA's efforts to
curtail outdoor cultivation. Indoor growers cultivate cannabis
in closets, fish tanks and elaborate greenhouses.
Some growers have even built structures that look like real
homes but lack interior walls, all to hide their
marijuana-growing operations. In 1998, drug law enforcement
authorities seized 2,616 indoor marijuana-growing operations.
Photo courtesy Marijuana.com
An array of marijuana plants growing under
More than 71 million Americans over the age of 12 had tried
marijuana as of 1998, which is more than 25 percent of the
national population. Frequent usage is lower than it was in
1979, when 13.2 percent of the U.S. population over the age of
12 was using marijuana on a monthly basis. In 1999, it had
declined to 5.1 percent.
There are several ways in
which people use marijuana, and the way in which it is used
determines the amount of chemicals transferred into the body,
according to the authors of "Buzzed."
Here are the most common methods of use:
SlangThere are hundreds of
slang words that mean "marijuana" (some refer to
specific types). Here are just a few:
Drug Enforcement Agency (DEA)
- Astro turf
- Aunt Mary
- Black Bart
- Chiba chiba
- Dinkie dow
- Mary Jane
- Maui wauie
- Yellow submarine
- Cigarette - Also called a joint, dried
marijuana leaves are rolled into a cigarette. Approximately
10 percent to 20 percent of the THC is transferred into the
body when smoking a joint.
- Cigar - Some users slice open a cigar, remove the
tobacco and refill it with marijuana. The marijuana-filled
cigar is often called a blunt.
- Pipe - You've probably seen people smoke pipes of
tobacco, but these pipes are also used to smoke marijuana.
About 40 percent to 50 percent of the THC is transferred
into the body when using a pipe.
- Bong - These are water pipes that
typically have a long tube rising out of a bowl-shaped base.
Water pipes trap the smoke until it's inhaled, raising the
amount of THC taken in.
- Food - Marijuana is sometimes baked into foods, such
as brownies, or brewed as tea.
With millions of users, marijuana use is not limited to one
demographic group. It cuts across all racial and economic
boundaries. However, marijuana use is highest among younger
people. The prevalence of marijuana use in teenagers doubled
from 1992 to 1999: One out of every 13 kids aged 12 to 17 were
current users of marijuana in 1999. The 1998 National Center
on Addiction and Substance Abuse indicates that marijuana is
very easy to obtain. Half of all 13-year-olds said that they
can find and purchase marijuana, according to the study. Of
teens surveyed, 49 percent said that they had first tried
marijuana at age 13 or younger.
Buying, selling, using or growing marijuana is illegal in
every part of the United States. Penalties vary from place to
place, but usually consist of jail time, a fine or both. In
some states, you can be arrested for just being in a place
where you know drug activity is taking place. The severity of
the penalty varies on several factors:
- Quantity - Penalties vary based on the amount of
marijuana found in the person's possession.
- Selling - Penalties are more severe for those
intending to sell.
- Growing - Penalties are also more severe for
those cultivating cannabis.
- Location - A person arrested for selling
marijuana near a school will often face harsher penalties.
page from NORML includes a state-by-state guide to
marijuana penalties. Click
here to see the federal trafficking penalties for
marijuana in the United States.
Jail sentences and fines have done little to suppress the
use of marijuana in the United States. Despite the health and
legal risks that come with using marijuana (or any illicit
drug), it continues to be the illegal drug of choice for many
Americans, as it has for decades.
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