Chapter 7 Marijuana
cannabis
is the shortened botanical term for the hemp plant cannabis sativa - with a potential height of about 18 feet, cannabis has sturdy stalks, four-cornered in cross-section, that have been commercially valuable for thousands of years in the manufacture of rope, twine, shoes, sailcloth, and containers of all kinds. - it is arguably the oldest cultivated plant not used for food
when animals or humans are studied in the laboratory,
marijuana smoking shows tolerance effects that are consistent and clear-cut
by the end of the 1920s and early 1930s
marijuana was known as "killer weed" because of the FBN
in the respiratory tract of heavy marijuana smokers,
molecular abnormalities have been identified that resemble the changes in the respiratory tracts of cigarette smokers. - the effect of a single marijuana joint is equivalent to that of up to five tobacco cigarettes in this regard - marijuana smoking does not increase the risk of developing emphysema, a chronic lung disease associated with tobacco smoking - occasional and low cumulative marijuana use does not produce adverse effects on lung capacity as indicated by standard pulmonary breathing tests
chronic marijuana users who have ingested higher levels of THC show
negative physical symptoms that are more severe and long lasting, resembling the withdrawal symptoms associated with the chronic use of tobacco. - these symptoms are substantially milder than those associated with the chronic use of heroin or alchohol
1969
when the US supreme court ruled the 1937 marijuana tax act unconstitutional precisely because marijuana possession was illegal
the causation question
- the intrinsic argument asserts that some inherent property of marijuana exposure itself leads to physical or psychological dependence on other illicit drugs - the sociocultural argument holds that the relationship exists not because of the pharmacological effects of marijuana abut because of the activities, friends, and acquaintances that are associated with marijuana smoking
the credibility of the amotivational syndrome theory revolves around two basic questions
(1) whether such a syndrome exists in the first place (2) whether chronic abuse of marijuana is a causal factor
cardiovascular effects
- THC produces significant increases in heart rate, but there is no conclusive evidence of adverse effects in the cardiovascular functioning in young, healthy people. - for those people with preexisting disorders such as heart disease, high blood pressure, or arteriosclerosis, it is known that the acute effects of marijuana on heart rate and blood pressure can worsen their condition
acute physiological effects
- a dose-related increase in heart rate during early stages of marijuana ingestion, up to 160 beats per minute when dose levels are high. blood pressure either increases, remains the same, or decreases, depending primarily on whether the individual is sitting, standing or lying down. a dilation of blood vessels on the cornea resulting in bloodshot eyes peaks about an hour after smoking a joint. frequently there is a drying of the mouth and an urge to drink.
other physiological reactions are inconsistent, and at least part of the inconsistency can be attributed to cultural and interpersonal influences
- having the munchies generally holds true in studies of North Americans but not Jamaicans, who consider marijuana an appetite suppressant
Depending on the growing conditions, cannabis will produce either a greater amount of fiber or a greater amount of resin
- in a cool, humid climate, such as North America, less resin is produced, but the fiber is stronger and more durable - in a warmer, less humid climate, such as North Africa, the fiber content is weak, but so much resin is produced that the plant looks as if it is covered in dew. - therefore, depending on environmental factors, you are getting a stronger rope or a stronger high
given all these factors, marijuana smoking presents several risks
- one of the immediate consequences affects the process of breathing. when marijuana is inhaled initially, the passageways for air entering and leaving the lungs widen, but after chronic exposure, an opposite reaction occurs. as a result, symptoms of asthma and other breathing difficulties are increased. - one joint is roughly equivalent to five cigarettes in terms of the amount of carbon monoxide intake and to four cigarettes in terms of tar intake.
effects on the brain
- special receptors in the brain are stimulated especially by THC - they are concentrated in areas of the brain that are important for short-term memory and motor control - THC-sensitive receptors are not found in the lower portions of the brain that control breathing - there is no danger of accidently death by asphyxiation
marijuana (sometimes spelled marihuana)
- the most commonly available psychoactive drug originating from the cannabis plant. the THC concentration ranges from approximately 1 to 6 percent -commonly referred to as a synonym for "cannabis" - obtained not from the stalks of the cannabis but from its serrated leaves. - the key psychoactive factor is contained in a sticky substance, or resin, that accumulates on these leaves.
respiratory effects and the risk of cancer
- the technique of marijuana smoking involves the deep and maintained inhalation into the lungs of unfiltered smoke on a repetitive basis - probably the worst possible scenario for incurring chronic pulmonary problems - marijuana joint (when compared with a tobacco cigarette) typically contains about the same levels of tar, 50 percent more hydrocarbons, and an unknown amount of possible contaminant
acute psychological and behavioral effects
Psychological - paranoia and increased anxiety - the high is a feeling of euphoria and well-being - an increased awareness of their surroundings, as well as a sharpened sense of sight and sound - everything is funny and they feel artistic - feeling sleepy or dreamy behavioral - decline in the ability to carry out task that involve attention and memory - speech becomes increasingly fragmented and disjointed - individuals often forget what they, or others, have just said - the problem is that marijuana typically causes such a rush of distracting ideas to come to mind that it is difficult to concentrate on new information coming in -by virtue of a diminished focus of concentration, the performance of both short-term and long-term memory tasks is impaired - these difficulties increase in magnetite as a direct function of the level of THC in the marijuana - complex motor tasks are poorly performed - decline in sensorimotor performance
effects on the immune system
THC has a suppressant effect on the immune system, resulting in a reduction in the body's defense reactions to infection and disease
hashish
a drug containing the resin of cannabis flowers. the THC concentration ranges from approximately 8 to 14 percent - can have THC concentration as high as 24 percent
hashish oil
a drug produced by boiling hashish, leaving a potent psychoactive residue. The THC concentration ranges from approximately 15 to 60 percent
sinsemilla
a form of marijuana obtained from the unpollinated or seedless portion of cannabis plant. it has a higher THC concentration than regular marijuana, as high as 15 percent - from the Spanish meaning "without seed"
bhang
a liquid form of marijuana popular in India - THC potency usually equal to that of a marijuana joint in the US
reefer or joint
a marijuana cigarette
anandamide
a naturally occurring chemical in the brain that fits into THC-sensitive receptors sites, producing many of the same effects as marijuana
cannabis sativa
a plant species, commonly called hemp, from which marijuana and hashish are obtained.
dronabinol
a prescription drug containing THC. brand name is Marinol
nabilone
a prescription drug containing a synthetic variation of THC. brand name is Cesamet
marijuana has often been regarded, in cultural terms, as
a reflection of an individual's attitude toward the establishment
hashish oil crystals
a solid form of hashish oil
amotivational syndrome
a state of listlessness and personality change involving a generalized apathy and indifference to long-range plans
cannabinoids
any of several dozen active substances in marijuana and other cannabis products - as many as 80 separate compounds, called cannabinoids, have been identified from cannabis resin - among these, the chief psychoactive compound and the active ingredient that produces the intoxicating effects is delta-9-tetrahydrocannabinol (THC)
the anti-marijuana fact has tended to
argue that marijuana should continue to be classified by the US federal government as a Schedule I controlled substance, along with heroin and LSD
in general, an experienced smoker will consume more THC than a novice smoker by virtue of
being able to inhale more deeply and hold the marijuana smoke in his or her lungs longer, for twenty-five seconds or more, thus maximizing THC absorption into the bloodstream
the pro-marijuana faction has tended to
dismiss or downplay reports of potential dangers and to emphasize the benefits
the inhalation of any drug into the lungs produces
extremely rapid absorption - in the case of THC, the effects are felt within seconds - peak levels are reached in the blood within ten minutes and start to decline shortly afterward - behavioral and psychological effects generally last from 2-3 hours - at this point, low levels of THC linger for several days because they are absorbed into fatty tissue, and exertion from fatty tissue is notoriously slow - one implication arising from a slow elimination rate is that the residual THC, left over from a previous administration, can intensify the effect of marijuana on a subsequent occasion
abstinence from smoking marijuana cigarettes with approximately 2 to 3 percent THC levels or equivalent oral doses of THC administered four times a day over a four-day period, resulted in
feelings of irritability, stomach pain, anxiety, and loss of appetite - these symptoms began within forty-eight hours and lasted at least two days
Does smoking marijuana produce a higher incidence of cancer?
given the number of known carcinogens in marijuana smoke, the potential for an increased risk of cancer exists. however, there is no definitive evidence of increases in lung cancer rates among marijuana smokers
the most point forms of cannabis are
hashish oil and hashish oil crystals
surveys that have examined accident rates among drivers testing positive for THC in their bloodstream
have shown them to be about three to seven times more likely to be involved in an accident than drivers testing negative for THC or alcohol
Why is the experience of humans outside the laboratory different from that of animals?
one important factor is the wy we measure the quantity of THC consumed - if you were to control the THC content entering the body, as is done in laboratory studies, you would find the predictable results of tolerance over repeated administration another fact that complicates tolerance studies is the slow elimination rate of marijuana - when dosage levels are controlled, the results indicate a consistent pattern of tolerance rather than sensitization. - in general, tolerance effects following repeated administrations of THC are greater as the dosage level of THC increases
withdrawal symptoms after discontinuance of marijuana smoking are observed in both
short-term and long-term marijuana users, even when relatively low levels of THC are ingested
marijuana clubs were called
tea pads
delta-9-tetrahydrocannabinol (THC)
the active psychoactive ingredient in marijuana and hashish
the gateway hypothesis
the idea that the abuse of a specific drug will inherently lead to the abuse of other, more harmful drugs
decriminalization
the policy of making the possession of small amounts of a drug subject to a small fine but not criminal prosecution
harrison act of 1914 & the marijuana tax act of 1937
the regulation of marijuana was accomplished indirectly. - the act did not ban marijuana; it merely required everyone connected with marijuana, from growers to buyers, to pay a tax
effects on sexual functioning and reproduction
the reproductive systems of both men and women are adversely affected by marijuana smoking. in men, marijuana reduces the level of testosterone, reduces sperm count in the semen, and increases the percentage of abnormally formed sperm. in women, marijuana use results in a reduction in the level of luteinizing hormone (LH), a hormone necessary for the fertilized egg to be implanted in the uterus. as little as one marijuana joint, smoked immediately following ovulation, is evidently sufficient for this LH suppression to occur - little to no effect on fertility has been observed
Exactly how much THC is administered depends on
the specific THC concentration level in the marijuana (often referred to as its quality), how deeply the smoke is inhaled into the lungs, and how long it is held in the lungs before being exhaled.
in the US as well as other western societies,
use of alcohol and cigarettes precedes marijuana use, and marijuana use precedes use of other illicit drugs
