What is it?
Marijuana is the greenish/brown or gray mixture of dried,
shredded leaves, seeds, stems and flowers (bud) of the hemp plant (Cannabis
sativa). There are several hundred slang and street names used for marijuana:
pot, herb, buddha-sticks, weed, grass, dope, Mary Jane, gangster, bango,
kif, joint, sticks, ganja, kind, boo or chronic. The strongest form of
marijuana is the Sinsemilla (flowers without the seed), hashish (the resin
extracted from the plant), or hash oil.
How does it work?
There are over 400 hundred different chemicals in marijuana,
about 60 of which are known as cannabinoids. These chemicals are found
nowhere else in nature. The most important cannabinoid in marijuana is
a known as delta-9 tetrahydrocannabinol (THC). THC is the main psychoactive
(mind-altering) ingredient in marijuana.
Researchers have recently discovered that certain areas
of the central nervous system (brain and spinal cord) have many THC receptors,
while others have very few or none. Receptors have also been found in
other parts of the body, specifically the spleen and the hematopoetic
Marijuana's effect on the user depends on the strength
or potency of the THC. THC potency of marijuana compared to that prior
to the 1970s has increased, but has remained about the same since the
middle of the 1980s.
Even though marijuana can be used in many ways, smoking
it seems to be the most popular. Following inhalation of smoke, the marijuana
is rapidly absorbed by the lungs, and into the blood, where it produces
its effects through specific binding (attachment) with endogenous THC
receptors in the brain.
Because THC is fat soluble (dissolves in fatty chemicals),
it and other marijuana metabolites can be stored in body fats and can
be traced throughout the body (e.g., in the lungs, liver and reproductive
organs) and the brain for long periods of time. Although these metabolites
may last for several days up to several weeks after a single dose of marijuana,
there is no evidence that the short-term effects (listed below) can last
longer than 6 hours. Traces of these metabolites also can be found in
the urine up to a week after use.
The THC receptors act like a keyhole, and are the binding
sites for various brain chemicals (neurotransmitters). When neurotransmitters
are attached to the receptors they instruct brain cells (neurons) to activate
and regulate various brain and body functions.
Dopamine is one such neurotransmitter. It originates in
the ventral tegmental area of the brain, and is associated with the feeling
of pleasurable sensations (being high). The neural systems trigger a dopamine
release that is known as the brain reward system. This reward system is
essential for our species' survival, without which, necessary pleasurable
activities such as eating and sexual intercourse would not be enjoyable,
and thus not take place as often as it should. Drugs of abuse that stimulate
or retard the uptake of dopamine once it has been released (cocaine blocks
the reuptake of dopamine and opiates activate neural pathways that increase
dopamine production) can, and often do, lead to adverse affects on behavior
and increase the risk of dependency or addiction.
Delta 9-THC in marijuana can augment brain dopamine neurotransmission,
and appears to have effects on the brain reward system similar to other
drugs of abuse. Also, Delta 9-THC binds with the mu receptors (opioid
receptors), which are involved in the pathways that lead to the release
of our own natural pain killing chemicals. This may explain the euphoric
morphine-like effects (getting high) reported by marijuana users.
In the brain, the highest concentration of THC receptors
are the CB1 receptors. These receptors are found in the hippocampus (where
memory is formed), cerebellum (deals with coordinating movements and balance),
amygdala, cortex and the basal ganglia. In the body, the presence of THC
receptors, known as CB2 receptors (found only in the spleen and immune
cells), may explain the effects of marijuana on the immune (body's natural
Marijuana differs from other drugs of abuse by the locations
of its brain receptor sites. There are not many CB1 receptors in the medulla
of the brain (where vital functions such as heart rate and respiration
are controlled). This would explain the lack of fatalities from marijuana.
In 1992, scientists discovered that the brain produces Anandamide (Sanskrit
for eternal bliss), a compound similar to THC. Its effects and functions
are undergoing further study.
What effect does marijuana have
on the body?
- Euphoria (feeling high).
- Impaired or reduced short-term memory -- the
recalling of verbal or graphic material is adversely affected.
- Altered perception of space and time.
- Increased muscular relaxation.
- Enhancement of sensory perception.
- Loss of the ability to concentrate.
- Decreased social inhibitions.
- Diminished ability to perform psychomotor tasks (e.g., driving).
- Loss of coordination.
- Decrease pain sensation.
- Increased heart rate.
- Increased systolic blood pressure.
- Bronchodilation (widening of airway tubes that carry air to the lungs).
- Decreased pressure inside the eye.
- Increased appetite.
- Bloodshot eyes.
- Dry mouth and throat.
- Increased thirst.
- Increased risk of injuries and accidents.
- May increase psychotic episodes in those prone to psychosis (such
as in schizophrenics).
- When smoked, marijuana contains chemicals such as
carbon monoxide, nitrosamines, and benzopyrene. Since it is often unfiltered
and held for long periods of time, it may lead to serious respiratory
problems such as mild airway obstruction, pre-cancerous changes, laryngitis
and bronchitis, as well as lung and neck cancer.
- Decrease in testosterone levels in men, including
the slowing of sperm motility and lower sperm counts.
- Increase in testosterone levels for women, with an
increased risk of infertility. It also decreases estrogen production,
and causes menstrual or ovulatory irregularities.
- Marijuana crosses the placental barrier, so use during
pregnancy is not recommended, and may have adverse effects.
- Decrease sexual libido or pleasure.
- Impairment of the immune system (a system that defends
the body against infections and cancers). It may, however, have effects
on diseases where there is an abnormal overactive immune response (autoimmune
diseases), such as multiple sclerosis. Further research in this area
- Psychological dependence develops.
- In chronic users, there is a condition called Amotivational
Syndrome, which describes a loss of ambition and indifference or passivity
towards achieving and realizing goals.
- Tolerance and dependence to a drug develops. More
and more of the drug is then necessary to achieve the same results.
Stopping the drug may even be associated with symptoms of withdrawal.
The symptoms of withdrawal start about 10-12 hours after the last time
of use, and peaks within 2 days, usually ending by the fifth day. This
may include irritability, restlessness, nervousness, insomnia, tremors,
increased REM sleep, decreased appetite and fever.
- Marijuana can contain fungal spores (aspergillus)
that may cause severe "opportunists" infections in those with a weakened
immune system due to medications or illnesses (cancer, AIDS, chemotherapy
or steroid therapy).
- Delta 9-THC-induced cell death with a shrinkage of
the neurons, as well as DNA fragmentation in the area of the hippocampus.
Are there any medicinal uses?
For thousands of years, marijuana has been used in many
cultures around the world for medicinal purposes. Some of these include:
- treatment of neuralgias
- headaches (including migraines)
- tic douloureaux
- anorexia nervosa
- chronic diarrhea
- topical anesthetic
- antiseptic (specially wounds)
- pain management during labor
- aphtous ulcers
In recent years, marijuana in the form of an FDA-approved
pill, Marinol or Nabilone, has been used to stimulate appetite and reduce
the nausea associated with cancer and chemotherapy.
Other potential benefits and uses of marijuana and metabolites
are under investigation. They include:
- As an adjunct agent for opiate, cocaine and alcohol
addiction, reducing use and easing the symptoms associated with withdrawal
from these more damaging drugs.
- In veterinary medicine.
- In regulating the immune system.
- To protect the brain from strokes and trauma damage.
- To alleviate pre-treatment anxiety in those receiving chemotherapy.
- In the treatment of glaucoma by reducing intraoccular pressure.
- In the treatment of Multiple Sclerosis, by reducing muscle pain and
spasticity, improving bladder control, relieving tremors and decreasing
seizures. In animal models of diseases similar to MS, it has been used
to reduce attacks on the nerves.
- To improve appetite and muscle mass
in the elderly with dementia and other wasting syndromes.
- As a potent antioxidant and anti-inflammatory.