|
| Marijuana Addiction |
Marijuana - often called pot, grass, reefer, weed, herb, mary jane, or mj - is a
greenish-gray mixture of the dried, shredded leaves, stems, seeds, and flowers
of Cannabis sativa, the hemp plant. Most users smoke marijuana in hand-rolled
cigarettes called joints, among other names; some use pipes or water pipes
called bongs. Marijuana cigars called blunts have also become popular. To make
blunts, users slice open cigars and replace the tobacco with marijuana, often
combined with another drug, such as crack cocaine. Marijuana also is used to
brew tea and is sometimes mixed into foods.
The major active chemical in marijuana is delta-9-tetrahydrocannabinol (THC),
which causes the mind-altering effects of marijuana intoxication. The amount of
THC (which is also the psychoactive ingredient in hashish) determines the
potency and, therefore, the effects of marijuana. Between 1980 and 1997, the
amount of THC in marijuana available in the United States rose dramatically.
Acute Effects of Marijuana Use
Marijuana's effects begin immediately after the drug enters the brain and last
from 1 to 3 hours. If marijuana is consumed in food or drink, the short-term
effects begin more slowly, usually in 1/2 to 1 hour, and last longer, for as
long as 4 hours. Smoking marijuana deposits several times more THC into the
blood than does eating or drinking the drug.
Within a few minutes after inhaling marijuana smoke, an individual's heart
begins beating more rapidly, the bronchial passages relax and become enlarged,
and blood vessels in the eyes expand, making the eyes look red. The heart rate,
normally 70 to 80 beats per minute, may increase by 20 to 50 beats per minute
or, in some cases, even double. This effect can be greater if other drugs are
taken with marijuana.
As THC enters the brain, it causes a user to feel euphoric - or "high" - by acting
in the brain's reward system, areas of the brain that respond to stimuli such as
food and drink as well as most drugs of abuse. THC activates the reward system in
the same way that nearly all drugs of abuse do, by stimulating brain cells to
release the chemical dopamine.
A marijuana user may experience pleasant sensations, colors and sounds may seem
more intense, and time appears to pass very slowly. The user's mouth feels dry,
and he or she may suddenly become very hungry and thirsty. His or her hands may
tremble and grow cold. The euphoria passes after awhile, and then the user may
feel sleepy or depressed. Occasionally, marijuana use produces anxiety, fear,
distrust, or panic.
Marijuana use impairs a person's ability to form memories, recall events
(see Marijuana, Memory, and the Hippocampus), and shift attention from one
thing to another. THC also disrupts coordination and balance by binding
to receptors in the cerebellum and basal ganglia, parts of the brain that
regulate balance, posture, coordination of movement, and reaction time.
Through its effects on the brain and body, marijuana intoxication can cause
accidents. Studies show that approximately 6 to 11 percent of fatal accident
victims test positive for THC. In many of these cases, alcohol is detected
as well.
In a study conducted by the National Highway Traffic Safety Administration,
a moderate dose of marijuana alone was shown to impair driving performance;
however, the effects of even a low dose of marijuana combined with alcohol
were markedly greater than for either drug alone. Driving indices measured
included reaction time, visual search frequency (driver checking side streets),
and the ability to perceive and/or respond to changes in the relative velocity
of other vehicles.
Marijuana users who have taken high doses of the drug may experience acute
toxic psychosis, which includes hallucinations, delusions, and
depersonalization - a loss of the sense of personal identity, or
self-recognition. Although the specific causes of these symptoms remain
unknown, they appear to occur more frequently when a high dose of cannabis is
consumed in food or drink rather than smoked.
Scientists have learned a great deal about how THC acts in the brain to produce
its many effects. When someone smokes marijuana, THC rapidly passes from the
lungs into the bloodstream, which carries the chemical to organs throughout
the body, including the brain. In the brain, THC connects to specific sites
called cannabinoid receptors on nerve cells and thereby influences the activity
of those cells. Some brain areas have many cannabinoid receptors; others have
few or none. Many cannabinoid receptors are found in the parts of the brain
that influence pleasure, memory, thought, concentration, sensory and time
perception, and coordinated movement.
What is the scope of marijuana use in the United States?
Marijuana is the Nation's most commonly used illicit drug. More than 83 million
Americans (37 percent) age 12 and older have tried marijuana at least once,
according to the 2001 National Household Survey on Drug Abuse (NHSDA).
Marijuana use is widespread among adolescents and young adults. The percentage
of middle-school students who reported using marijuana increased throughout the
early 1990s. In the past few years, according to the 2001 Monitoring the
Future Study, an annual survey of drug use among the Nation's middle- and
high-school students, illicit drug use by 8th-, 10th-, and 12th-graders has
leveled off. Still, in 2001, 20 percent of 8th-graders reported that they
had tried marijuana, and 9 percent were current users (defined as having used
the drug in the 30 days preceding the survey). Among 10th-graders, 40 percent
had tried marijuana sometime in their lives, and almost 20 percent were current
users. As would be expected, rates of use among 12th-graders were higher
still: Nearly half had tried marijuana at some time, and 22 percent were
current users.
The Drug Abuse Warning Network (DAWN), a system for monitoring the health
impact of drugs, estimated that, in 2001, marijuana was a contributing factor
in more than 110,000 emergency department (ED) visits in the United States,
with about 15 percent of the patients between the ages of 12 and 17, and almost
two-thirds male.
In 1999, the National Institute of Justice's Arrestee Drug Abuse Monitoring
Program (ADAM), which collects data from 34 sites on the number of adult
arrestees testing positive for various drugs, found that, on average, 39
percent of adult male arrestees and 26 percent of adult female arrestees tested
positive for marijuana. ADAM collected data on juvenile arrestees in nine
sites and found that marijuana was the most commonly used drug among these
youths. On average, 53 percent of juvenile male and 38 percent of juvenile
female arrestees tested positive for marijuana.
NIDA's Community Epidemiology Work Group (CEWG), a network of researchers that
tracks trends in the nature and patterns of drug use in major U.S. cities,
consistently reports that marijuana frequently is combined with other drugs,
such as crack cocaine, PCP, formaldehyde, and codeine cough syrup, sometimes
without the user being aware of it. Thus, the risks associated with marijuana
use may be compounded by the risks of added drugs, as well.
How does marijuana use affect school, work, and social life?
Students who smoke marijuana get lower grades and are less likely to graduate
from high school, compared with their nonsmoking peers. In one study,
researchers compared marijuana smoking and nonsmoking 12th-graders' scores on
standardized tests of verbal and mathematical skills. Although all of the
students had scored equally well in 4th grade, the smokers' scores were
significantly lower in 12th grade than the nonsmokers' scores were.
Workers who smoke marijuana are more likely than their co-workers to have
problems on the job. Several studies have associated workers' marijuana
smoking with increased absences, tardiness, accidents, workers' compensation
claims, and job turnover. A study among municipal workers found that
employees who smoked marijuana on or off the job reported more "withdrawal
behaviors" - such as leaving work without permission, daydreaming, spending
work time on personal matters, and shirking tasks - that adversely affect
productivity and morale.
Depression, anxiety, and personality disturbances are all associated with
marijuana use. Research clearly demonstrates that marijuana use has the
potential to cause problems in daily life or make a person's existing
problems worse. Because marijuana compromises the ability to learn and
remember information, the more a person uses marijuana the more he or she is
likely to fall behind in accumulating intellectual, job, or social skills.
Moreover, research has shown that marijuana's adverse impact on memory and
learning can last for days or weeks after the acute effects of the drug wear
off.
For example, a study of 129 college students found that among heavy users of
marijuana, those who smoked the drug at least 27 of the preceding 30 days,
critical skills related to attention, memory, and learning were significantly
impaired, even after they had not used the drug for at least 24 hours. The
heavy marijuana users in the study had more trouble sustaining and shifting
their attention and in registering, organizing, and using information than
did the study participants who had used marijuana no more than 3 of the
previous 30 days. As a result, someone who smokes marijuana once daily may
be functioning at a reduced intellectual level all of the time. More
recently, the same researchers showed that a group of long-term heavy
marijuana users' ability to recall words from a list was impaired 1 week
following cessation of marijuana use, but returned to normal by 4 weeks.
An implication of this finding is that even after long-term heavy marijuana
use, if an individual quits marijuana use, some cognitive abilities may be
recovered.
Another study produced additional evidence that marijuana's effects on the
brain can cause cumulative deterioration of critical life skills in the
long run. Researchers gave students a battery of tests measuring
problem-solving and emotional skills in 8th grade and again in 12th grade.
The results showed that the students who were already drinking alcohol plus
smoking marijuana in 8th grade started off slightly behind their peers but
that the distance separating these two groups grew significantly by their
senior year in high school. The analysis linked marijuana use, independently
of alcohol use, to reduced capacity for self-reinforcement, a group of
psychological skills that enable individuals to maintain confidence and
persevere in the pursuit of goals.
How does marijuana use affect physical health?
Marijuana use has been shown to increase users' difficulty in trying to quit
smoking tobacco. This was recently reported in a study comparing smoking
cessation in adults who smoked both marijuana and tobacco with those who
smoked only tobacco. The relationship between marijuana use and continued
smoking was particularly strong in those who smoked marijuana daily at the
time of the initial interview, 13 years prior to the followup interview.
A study of 450 individuals found that people who smoke marijuana frequently
but do not smoke tobacco have more health problems and miss more days of
work than nonsmokers do. Many of the extra sick days used by the marijuana
smokers in the study were for respiratory illnesses.
Even infrequent marijuana use can cause burning and stinging of the mouth and
throat, often accompanied by a heavy cough. Someone who smokes marijuana
regularly may have many of the same respiratory problems that tobacco smokers
do, such as daily cough and phlegm production, more frequent acute chest
illnesses, a heightened risk of lung infections, and a greater tendency toward
obstructed airways.
Cancer of the respiratory tract and lungs may also be promoted by marijuana
smoke. A study comparing 173 cancer patients and 176 healthy individuals
produced strong evidence that smoking marijuana increases the likelihood of
developing cancer of the head or neck, and that the more marijuana smoked, the
greater the increase.18 A statistical analysis of the data suggested that
marijuana smoking doubled or tripled the risk of these cancers.
Marijuana has the potential to promote cancer of the lungs and other parts
of the respiratory tract because it contains irritants and carcinogens. In
fact, marijuana smoke contains 50 percent to 70 percent more carcinogenic
hydrocarbons than does tobacco smoke. It also produces high levels of an
enzyme that converts certain hydrocarbons into their carcinogenic form,
levels that may accelerate the changes that ultimately produce malignant
cells. Marijuana users usually inhale more deeply and hold their breath
longer than tobacco smokers do, which increases the lungs' exposure to
carcinogenic smoke. These facts suggest that, puff for puff, smoking
marijuana may increase the risk of cancer more than smoking tobacco does.
Some adverse health effects caused by marijuana may occur because THC
impairs the immune system's ability to fight off infectious diseases and cancer.
In laboratory experiments that exposed animal and human cells to THC or other
marijuana ingredients, the normal disease-preventing reactions of many of the
key types of immune cells were inhibited. In other studies, mice exposed to
THC or related substances were more likely than unexposed mice to develop
bacterial infections and tumors.
One study has indicated that a person's risk of heart attack during the first
hour after smoking marijuana is four times his or her usual risk. The
researchers suggest that a heart attack might occur, in part, because marijuana
raises blood pressure and heart rate and reduces the oxygen-carrying capacity of
blood.
| Marijuana,
Memory, and the Hippocampus |
Marijuana's damage to short-term
memory seems to occur because THC alters the way
in which information is processed by the hippocampus,
a brain area responsible for memory formation. Laboratory
rats treated with THC displayed the same reduced
ability to perform tasks requiring short-term memory
as other rats showed after nerve cells in their
hippocampus were destroyed.
In addition, the THC-treated rats had the greatest
difficulty with the tasks precisely during the time
when the drug was interfering most with the normal
functioning of cells in the hippocampus.
As people age, they normally lose neurons in the
hippocampus, which decreases their ability to remember
events. Chronic THC exposure may hasten the age-related
loss of hippocampal neurons. In one series of studies,
rats exposed to THC every day for 8 months (approximately
30 percent of their lifespan), when examined at
11 to 12 months of age, showed nerve cell loss equivalent
to that of unexposed animals twice their age. |
| The Body's Natural THC-Like Chemicals |
THC owes many of its effects
to its similarity to a family of chemicals called
the endogenous cannabinoids, which are natural
Cannabis-like chemicals. Because a THC molecule
is shaped like these endogenous cannabinoids, it
interacts with the same receptors on nerve cells,
the cannabinoid receptors, that endogenous cannabinoids
do, and it influences many of the same processes.
Research has shown that the endogenous cannabinoids
help control a wide array of mental and physical
processes in the brain and throughout the body,
including memory and perception, fine motor coordination,
pain sensations,
immunity to disease, and reproduction.
When someone smokes marijuana, THC overstimulates
the cannabinoid receptors, leading to a disruption
of the endogenous cannabinoids' normal control.
This overstimulation produces the intoxication experienced
by marijuana smokers. Over time, it may degrade
some cannabinoid receptors, possibly producing permanent
adverse effects and contributing to addiction and
risk for a withdrawal syndrome.
|
| The Science
of Medical Marijuana
|
THC, the main active ingredient
in marijuana, produces effects that potentially
can be useful for treating a variety of medical
conditions. It is the main ingredient in an oral
medication that is currently used to treat nausea
in cancer chemotherapy patients and to stimulate
appetite in patients with wasting due to AIDS. Scientists
are continuing to investigate other potential medical
uses for cannabinoids.
Research is underway to examine the effects of smoked
marijuana and extracts of marijuana on appetite
stimulation, certain types of pain, and spasticity
due to multiple sclerosis.
Some clinical trials of smoked marijuana for therapy
are underway, but the inconsistency of THC dosage
in different marijuana samples poses a major hindrance
to valid trials and to the safe and effective use
of the drug. Moreover, the adverse effects of marijuana
smoke on the respiratory system will offset the
helpfulness of smoked marijuana for some patients.
Finally, little is known about the many chemicals
besides THC that are in marijuana, or their possible
deleterious impact on patients with medical conditions.
|
Can marijuana use during pregnancy harm the baby?
Research has shown that babies born to women who used marijuana during their
pregnancies display altered responses to visual stimuli, increased
tremulousness, and a high-pitched cry, which may indicate problems with
neurological development. During infancy and preschool years,
marijuana-exposed children have been observed to have more behavioral
problems and to perform tasks of visual perception, language comprehension,
sustained attention, and memory more poorly than nonexposed children do.
In school, these children are more likely to exhibit deficits in decision-making
skills, memory, and the ability to remain attentive.
Is marijuana use addictive?
Long-term marijuana use can lead to addiction for some people; that is, they
use the drug compulsively even though it often interferes with family,
school, work, and recreational activities. According to the 2001 National
Household Survey on Drug Abuse, an estimated 5.6 million Americans age 12
or older reported problems with illicit drug use in the past year. Of
these, 3.6 million met diagnostic criteria for dependence on an illicit
drug. More than 2 million met diagnostic criteria for dependence on
marijuana/hashish. In 1999, more than 220,000 people entering drug abuse
treatment programs reported that marijuana was their primary drug of abuse.
Along with craving, withdrawal symptoms can make it hard for long-term
marijuana smokers to stop using the drug. People trying to quit report
irritability, difficulty sleeping, and anxiety. They also display increased
aggression on psychological tests, peaking approximately 1 week after they
last used the drug.
What treatments are available for marijuana abusers?
Treatment programs directed at marijuana abuse are rare, partly because many
who use marijuana do so in combination with other drugs, such as cocaine and
alcohol. However, with more people seeking help to control marijuana abuse,
research has focused on ways to overcome problems with abuse of this drug.
One study of adult marijuana users found comparable benefits from a
14-session cognitive-behavioral group treatment and a 2-session individual
treatment that included motivational interviewing and advice on ways to
reduce marijuana use. Participants were mostly men in their early thirties
who had smoked marijuana daily for over 10 years. By increasing patients'
awareness of what triggers their marijuana use, both treatments sought to
help them devise avoidance strategies. Use, dependence symptoms, and
psychosocial problems decreased for at least 1 year after both treatments.
About 30 percent of users were abstinent during the last 3-month followup
period. Another study suggests that giving patients vouchers for abstaining
from marijuana can improve outcomes. Vouchers can be redeemed for such
goods as movie passes, sports equipment, or vocational training.
No medications are now available to treat marijuana abuse. However, recent
discoveries about the workings of THC receptors have raised the possibility
that scientists may eventually develop a medication that will block THC's
intoxicating effects. Such a medication might be used to prevent relapse to
marijuana abuse by reducing or eliminating its appeal.
|
|
|
|
|
|
|
|
|
Recent Listings
|
 |
Vista Taos Renewal Center
Taos, New Mexico, United States
Private, residential treatment center in New
05-18-2010
|
|
Buffalo Valley, Inc
Lewisburg, Tennessee, United States
Drug and Alcohol Treatment Center
04-29-2010
|
|
Pathway Interventions LLC
Sandy, Utah, United States
The Intervention Specialist helping those who are
08-10-2009
|
|
The Turning Point Foundation
New Haven, Connecticut, United States
The Turning Point Foundation is a non–profit
07-10-2009
|
|
Womens Transitional living
Phoenix, Arizona, United States
Womens halfway house
05-22-2009
|
|
|
