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Chapter 11   Marijuana
 

Chapter 11 Marijuana

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    Chapter 11   Marijuana Chapter 11 Marijuana Presentation Transcript

    • Marijuana Chapter 11
    • Introduction
      • The plant Cannabis sativa is more commonly known as marijuana, a hemp plant that grows freely throughout the world
      • It once was harvested primarily for its fiber which was used for making rope, clothes and ship sails, but now is grown for its psychoactive effects
      • Marijuana is the leafy top portion of the plant, and hashish is the resin the plant produces to protect it from the sun and maintain hydration
    • Historical Overview
      • Use of cannabis for its intoxicating effects began in Asia and gradually spread to the Middle East and then to North Africa.
      • In China it was used for sedating, treating pain and illness, countering the influences of evil spirits, and for its psychoactive effects
      • In India it was given religious significance and considered one of five sacred plants
      • It was not until the 19 th century that the Western world began to be exposed to cannabis through medical writings and the press
      • Cannabis in the New World dates to 1543, when it was brought to Chile by the Spaniards
      • It was raised in the colonies only for its fiber and was relatively unknown as a mind-altering substance
      • American physicians used cannabis in the 1800s as a general, all-purpose medication
      • It was consumed for recreational purposes only to a limited extent during this period and descriptions of its psychoactive effects were not common
      • The exception is the publication of the book The Hasheesh Eater in 1857 where Fritz Hugh Ludlow describes his cannabis-eating experiences over a four year period
      • The 1920s brought a wider use of cannabis, an increase attributed to alcohol prohibition. Marijuana “tea-pads” (comparable to the “speakeasy”), opened at this time
      • Tea-pad – Historically, a place where people gathered to smoke marijuana. The site could be anything from a rented room to a hotel suite
      • In 1926 a series of articles appeared in two New Orleans newspapers exposing the “menacing” presence of marijuana and attributing a number of crimes and heinous acts to its use.
      • Though many of the reports were ridiculous and fabricated, the following year the first legal action against marijuana was taken when a Louisiana law was passed mandating a maximum penalty of a $500 fine and/or six months imprisonment for conviction of possession or sale of marijuana
      • Additional government and legal action continued after Harry J. Anslinger became Director of the Federal Bureau of narcotics in 1932.
      • In 1937, the Marijuana Tax Act was passed outlawing use of marijuana unless it was prescribed by a licensed physician.
      • Punishments for violation were $2,000 fine, five years imprisonment, or both. By the 1960s, a user or seller of marijuana could get life imprisonment, or even death for a second offense of selling to a minor
    • Committee Reports on Marijuana
      • Several influential reports have appeared on the use of marijuana and its effects, including the 1894 Indian Hemp Drugs Commission Report and the 1944 LaGuardia Commission Report. Such reports found that marijuana use overall was not particularly harmful to society at large and subsequent reports, though more cautious in describing nonnegative effects, did not provide markedly discrepant findings. Some supported the use of marijuana for pain relief, control of nausea and vomiting, and appetite stimulation
      • The 2002 report: Cannabis: Our Position for a Canadian Public Policy (Senate Special Committee on Illegal Drugs) made the following recommendations:
        • Amendments to existing law to allow compassionate medical access to cannabis and its derivatives.
        • 2) A system through which licensed individuals would produce and sell cannabis.
        • 3) Government of Canada declare an amnesty for any person convicted of possession of cannabis under current or past legislation.
    • Epidemiology
      • Marijuana is the most widely used illicit drug in the Western World and the third most commonly used recreational drug after alcohol and tobacco
      • It is the most frequently used illicit drug in the United States, although its use has decreased over the last decade
      • Reasons for the decrease are thought to reflect broad cultural factors, growing concerns about health and fitness, and concerns over possible negative effects of drug use in general
      • The exception is with high school seniors where the 2004 National Household Survey on Drug Abuse reported a significant increase in use from 1993 through 1997 which remained relatively constant until 2000 when it began to decrease again
      • Attitudes and beliefs about drugs appears to have “softened” among high school students as they tended to believe less strongly about the dangers associated with the use of drugs and about their personal disapproval of using them
      • Also, according to the survey, 97 million Americans (40% of the population) have used marijuana at least once in their lives
      • Men were more likely than women to be current users of marijuana (8.0% versus 4.3%)
      • Current prevalence was 9.1% among American Indians/Alaska Natives, 7% among Blacks, 6.2% among Whites, and 5% among Hispanics
    • Methods of Use
      • Marijuana and hashish have been administered in a number of ways, i.e., they can be ingested in both liquid and food form, and people can experience psychoactive effects by chewing marijuana leaves. However, the most common and efficient procedure for ingestion is smoking, typically in cigarette ( joint ) form
      • Joint – A hand-rolled marijuana cigarette
      • Inhalation through cigarettes is the most rapid and efficient method for absorption of cannabis
    • Active Ingredients
      • Cannabis is a complex plant with more than 400 individual chemical compounds, 60 of them, called cannabinoids , unique to the cannabis plant
      • Cannabinoids – The more than 60 chemical compounds present in cannabis. One is delta-9-tetrahydrocannabinol (better known as THC)
      • Delta-9-Tetrahydrocannabinol – Isolated in 1964, the principal active cannabinoid in marijuana responsible for the psychoactive effects
    • Potency
      • Marijuana grown in the U.S. has a THC content lower than marijuana grown overseas, yet it is stronger (4-5%) than before (2% in 1980)
      • Higher THC potency is found in “home-grown” varieties that average 10-15% and can reach as much as 30%
      • Similar variations and increasing potencies have been found in hashish
      • Hash Oil – A potent distillate of marijuana or hashish first appeared in the United States in 1971 and can contain up to 60% THC, though generally is around 20%
    • Absorption, Distribution, Metabolism, and Excretion
      • Inhalation results in absorption directly through the lungs, and the onset of THC action begins in minutes
      • Peak concentrations occur 30-60 minutes later
      • Drug effects can be experienced for 2-4 hours
      • Factors that influence the amount of THC absorbed through smoking include: potency of cannabis being smoked, amount of time the smoke is held in the lungs, and number of smokers who share the cigarette
      • Oral ingestion is much slower and relatively inefficient
      • Onset of action can take up to an hour and peak levels can be delayed as long as 2-3 hours after ingestion
      • Drug effects can be experienced for longer periods of time, generally 4-6 hours
      • The dose needed to create a comparable high when ingested is three times greater than that needed when smoking
      • THC is lipid-soluble and is thus deposited in the tissues of fatty organs such as the brain, lungs, kidneys, and liver
      • Thus, even when blood levels of THC are zero, levels of THC in other organs can be substantial
      • THC is capable of crossing the placental barrier and reaching the fetus
      • Most metabolites are excreted slowly through the feces and urine in about a week, yet some can be detected in the body 30 days after ingestion, or up to several weeks in the urine after chronic use
    • Mechanisms of Action
      • The main actions of marijuana occur in the brain and result from the drug’s effect on neurotransmitters such as acetylcholine, serotonin, and dopamine
      • Recent advances in research include work on THC receptors in the brain
      • The chemical “ anandamide ” which binds to the same receptors on brain cells as do cannabinoids, is being used to study how cannabinoid receptors affect functions affected by marijuana use such as memory, movement, hunger, and pain
    • Tolerance and Dependence
      • Tolerance to cannabis has been well documented in animal species, yet is less clear in humans
      • When it occurs, it is most likely when high doses are used over extended periods of time
      • Physical dependence is rare and to date no significant withdrawal syndrome has been identified
      • Symptoms that have been reported include: sleep disturbance, nausea, irritability, and restlessness but it is argued these indicate psychological dependence
    • Medical and Psychotherapeutic Uses
      • Cannabis has long been used for medicinal and psychotherapeutic purposes
      • Today, it and THC synthetics are used mostly to reduce nausea and vomiting associated with cancer chemotherapies and as an appetite stimulant among patients with cachexia
      • Cachexia – A disorder in which an individual physiologically “wastes away”, often due to HIV infection or cancer
      • There has been a resurgence in efforts to legalize marijuana for medicinal purposes
      • Though the synthetics such as Marinol and Cesamet provide the active elements of THC in a more stable manner and provide better solubility, there is an absence of the rapid effect experienced when marijuana is smoked
      • A new cannabis oral spray (trade name Sativex) which has been approved in Canada for use as a painkiller for sufferers of multiple sclerosis, counters the downside of delayed absorption from other synthetics taken orally that lose the rapid effect experienced when marijuana is smoked
      • The main drawback to the use of both cannabis and THC synthetics is the resultant mental effects, which have been viewed by some as uncomfortable and disorienting
      • A synthetic analog of THC called ajulemic acid is receiving attention as an analgesic that does not produce feelings of being “high”.
      • Glaucoma – A generic term used to denote ocular diseases that involve increases in intraocular pressure. This pressure damages the optic nerve and represents the leading cause of blindness in the United States
      • Cannabis has been shown to decrease intraocular pressure, though patients experience side effects such as increased heart rate, psychological effects, and reduced blood flow to the optic nerve that may possibly exacerbate the loss of vision
    • Physiological Effects
      • Acute effects include bloodshot eyes, increased heart rate and pulse rate, slight elevation in blood pressure, and decreased motor activity (the exception to this is increased talkative behavior of many smokers)
      • Some users report drowsiness, dry mouth, thirst, fluctuations in respiration and body temperature, hunger or “the munchies” (peaking 2-3 hours after smoking), nausea, and headache or dizziness
      • Cannabis in higher doses can effect sleep stages, tending to decrease REM sleep
      • Research on the long-term effects of marijuana is sparse and difficult to interpret
      • Proper lung functioning appears to be altered but much of this impairment is reversed following abstinence
      • Marijuana cigarettes contain more tar than tobacco cigarettes and cannabis tar contains greater amounts of cancerous agents
      • Marijuana smokers may also be at greater risk because they inhale deeply and hold the smoke in their lungs longer
      • No evidence shows smoking marijuana produces deleterious cardiovascular effects among healthy individuals, however, the acute effects of increased heart rate could be potentially dangerous among persons who have existing cardiovascular problems
      • Although early research suggested this, it appears now that cannabis poses no significant long-term threat to the immune system
      • It does act as an immunosuppressant and decreases resistance to some viruses and bacteria
      • Cannabis disrupts the reproductive system in both males and females
      • Chronic marijuana use has been associated with decreases in the number of sperm and sperm motility in men and nonovulatory menstrual cycles in women
      • Use by pregnant women is associated with increased risk of premature birth, shorter body length, and lower infant birth weight
      • Newborn infants have been noted to exhibit tremor, startle response, and altered visual responses
      • Longer-term consequences include deficits on a sustained attention task at age 6, and to be more impulsive, hyperactive, and delinquent at age 10
      • The majority of effects associated with marijuana use are more acute than chronic and longer term effects tend to be reversible with termination of use
      • Most negative effects are correlated with higher doses and greater frequency of use than most smokers report
      • Smoking marijuana may be linked to various respiratory disorders
    • Psychological Effects
      • Psychological effects can be divided into three domains: behavioral, cognitive, and emotional
      • Behavioral effects include decreased psychomotor activity which is associated with feelings of relaxation, tranquility, and a sense of well-being
      • Some users first experience a stage in which they feel excited and restless
      • Users may feel their senses are markedly keener and describe more intense perceptions of touch, vision (especially colors), hearing, and smell
      • There is a decreased sensitivity to pain
      • There appears to be dose-related dysfunctions in motor coordination, signal detection, and the ability to monitor a moving object which obviously has implications for driving. In fact, laboratory studies with a driving simulator have shown detrimental effects on driving skill
      • Some report that sexual pleasures are more intense and enjoyable whereas others describe a disinterest in sex
      • Cognitive effects include impaired short-term memory, the perception that time passes more slowly, decreased ability to attend and concentrate causing increased distractibility, and racing thoughts and “flight of ideas”
      • Writers and painters report enhanced creativity, and some users describe occasional feelings of “unreality”
      • Research on persistent cognitive effects from long-term marijuana use is at best equivocal
      • Positive emotional changes are cited as key motivators to smoke marijuana
      • Alterations in mood are thought to result from nondrug influences such as past experience with cannabis, attitudes about the drug, expectancies regarding the drug use consequences, and the situational context of drug use as well as the dose of THC absorbed
      • The typical emotional response is a carefree and relaxed state described as euphoric, content, happy, and excited
      • Though the response is generally viewed as pleasant and positive, negative emotional feelings such as anxiety or dysphoria are more common than might be expected
      • A variety of somatic consequences have been reported including headache, nausea, and muscle tension
      • Less frequently, suspiciousness and paranoid ideation have occurred
      • About a third of users occasionally experience some negative effects and they are often inexperienced cannabis users
    • Social and Environmental Effects
      • Though some report they use marijuana because it enhances their social skills and allows them to be more competent in social situations, the research does not support this. It is likely the user is more relaxed in the situation and thus perceives less anxiety, or interprets his or her behavior differently while under the influence
      • Cannabis use is not causally related to increased aggression. In fact, levels of aggression actually decrease following cannabis use
      • The most controversial social / environmental consequence of cannabis use is the amotivational syndrome
      • Amotivational Syndrome – Loss of effectiveness and reduced capacity to accomplish conventional goals as a result of chronic marijuana use
      • List of behaviors proposed as part of the syndrome include apathy, decreased effectiveness, lost ambition, decreased sense of goals, and difficulty in attending and concentrating
      • The phenomenon is most likely to be seen among younger users who are using marijuana daily or heavily, however, the syndrome has not been seen in all daily or heavy users and has been seen in youths who do not use marijuana
      • There is also some debate about how commonly the syndrome occurs, with some studies citing it as fairly infrequent
      • Preexisting personality characteristics and some drug effects together probably account for what has been labeled the amotivational syndrome