20120527-cannabis ReeferMadness_09.JPG
Scene from Reefer Madness
Some people who smoke cannabis a lot get paranoid or extremely lazy. Some don’t leave their homes much, and spend most of their time getting high. Long term, heavy users sometimes have distorted perception, slow reaction times, impaired coordination and marginalized driving skills, especially when they are high. In extreme cases heavy users develop irrational fears, become seriously withdrawn and lose control. There have been reports of heavy users suffering from schizophrenic attacks and having their blood flows interfered with to such a degree they had their limbs amputated. But it is not clear whether cannabis was responsible for these maladies. Many of the studies are incomplete, flawed in some way or have inconclusive results. They some insight on the issues they address but fail to make point conclusively or not. Claims made in the 1970s and 80s that marijuana causes brain damage, chromosome damage, sterility, infertility and even homosexuality were never proven.

Cannabis use has also been linked to other mental health problems, such as depression, anxiety, and suicidal thoughts among teens. However, study findings have been mixed. Compared to those who don't use cannabis, those who frequently use large amounts report the following: lower life satisfaction, poorer mental health, poorer physical health and more relationship problems People also report less academic and career success. For example, cannabis use is linked to a higher likelihood of dropping out of school. It's also linked to more job absences, accidents, and injuries. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

One of the main arguments traditionally made against cannabis is that is of it lead the use of harder drugs such as cocaine and heroin. Cannabis does not seem to be a "gateway" to harder drugs. Studies have shown that beer and cigarettes seem to be gateways to cannabis but cannabis is not a gate way to other drugs. The majority of people who use cannabis don't go on to use other "harder" drugs.

The amount of THC in cannabis has been increasing steadily over the past few decades. For a person who's new to cannabis use, this may mean exposure to higher THC levels with a greater chance of a harmful reaction. Higher THC levels may explain the rise in emergency room visits involving cannabis use. The popularity of edibles also increases the chance of harmful reactions. Edibles take longer to digest and produce a high. Therefore, people may consume more to feel the effects faster, leading to dangerous results. Higher THC levels may also mean a greater risk for addiction if people are regularly exposing themselves to high doses. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

Websites and Resources: U.S. Drug Enforcement Administration (DEA) ; Vaults of Erowid ; United Nations Office of Drugs and Crime (UNODC) ; Wikipedia article on illegal drug trade Wikipedia ; Frank’s A-to-Z on Drugs ; ; Illegal Drugs, country by country listing, CIA

Books: “Buzzed” by Cynthia Kuhn Ph.D. Scott Swartzwelder, Ph.D., Wilkie Wilson Ph.D. of the Duke University Medical Center (Norton, 2003); “Consuming Habits: Drugs in Anthropology and History” by Goodman, Sharratt and Lovejoy; “Drug War Heresies: Learning from Other Vices, Times and Places” by Robert MacCoun and Peter Reuter (Cambridge University Press).

Cannabis and Poor Health

The primary dangers from cannabis are posed by tars, carcinogens and other substances in the smoke. Cannabis smoke contains more than 400 different chemical compounds, some which are carcinogens. According to major report done by the United States government, "Numerous studies suggest that cannabis smoke is an important risk factor in the development of respiratory disease" and is associated with an increased risk of cancer, lung damage and poor pregnancy outcomes. Studies on cell cultures at the Argonne National Laboratory in Illinois shows that THC affects the development of immune-system cells. In the laboratory immature white blood cells exposed to THC never developed to the a point where effectively fight disease.

Studies have shown that marijuana and hashish can be harmful to the lung, impair brain functions, slow down the immune system and affect the physiology of fetuses. Cannabis raises heart rate for up to three hours after smoking. This effect may increase the chance of heart attack. Older people and those with heart problems may be at higher risk. One study showed that middle-aged people their risk of a heart attack rose by nearly five times in the first hour after smoking cannabis. Others show that cannabis changes the heart rate and lowers blood pressure. Regular, long-term cannabis use can lead to some people to develop Cannabinoid Hyperemesis Syndrome. This causes users to experience regular cycles of severe nausea, vomiting, and dehydration, sometimes requiring emergency medical attention.

Cannabis use during pregnancy is linked to lower birth weight and increased risk of both brain and behavioral problems in babies. Children exposed to cannabis in the womb have an increased risk of problems with attention, memory, and problem-solving compared to unexposed children. A five-year Canadian study showed that babies born to mothers who smoked cannabis were more likely than babies of nonsmokers to have problems with vision, tremors and reflexes although these problems usually disappeared or declined several months after the babies' birth. Some research also suggests that moderate amounts of THC are excreted into the breast milk of nursing mothers. With regular use, THC can reach amounts in breast milk that could affect the baby's developing brain. Other recent research suggests an increased risk of preterm births. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

Cannabis and the Lungs

Cannabis smoke irritates the lungs, and people who smoke cannabis frequently can have the same breathing problems as those who smoke tobacco. These problems include daily cough and phlegm, more frequent lung illness, and a higher risk of lung infections. Researchers so far haven't found a higher risk for lung cancer in people who smoke cannabis. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

A study done by the New England Journal of Medicine has shown the amount of carbon monoxide in the bloodstream of a cannabis user who smokes one joint is five times the amount of carbon monoxide in the bloodstream of tobacco smoker who smokes one cigarette. The same study showed that the amount of tar in the lungs of a pot smoker is four times that of cigarette smoker. One reason for the high carbon monoxide and tar figures is that is that cannabis smokers generally inhale more smoke than cigarette smokers and hold the smoke in their lungs almost four times as long which gives the tar more time to settle in the lungs and the carbon dioxide more time to be absorbed into the blood.

U.C.L.A. respiratory specialist Donald Tashkin told Discover magazine, "smokers of only a few joints a day have as much microscopic damage to the cells lining in their airways as smokers of more than a pack of cigarettes a day." It is "the same kind of change that one sees in long-term tobacco smokers who go on to develop lung cancer."

University of Arizona respiratory specialist John Bloom told Discover that people who smoked several joints a day had lung damage worse than tobacco smokers. "This group is under 40 years of age," he said. "It is unusual to find evidence of abnormality, even from tobacco smoking, in this young group. Considering that they were smoking an average of 6.7 [joints] each week, it seems that a relatively small amount of smoking these things causes an apparent effect."

Links between cannabis smoking and lung cancer have not been shown with the certainty as links between tobacco and lung cancer but this is mainly because cannabis smoking is a relatively new phenomena and lung cancer often takes decades to reveal itself and cannabis and cancer have not been studied as throughly and as long as tobacco and cancer.

Cannabis and the Brain

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Brain of marijuana user
According to a 1997 World Health Organization Report, cannabis "acutely impairs cognitive development and psychomotor performance, which increase the risk of motor vehicle accidents among those who drive intoxicated." A significant number of people involved in automobile accidents have THC in their blood. Most of these people had alcohol in their blood too.

Cannabis affects brain development. When people begin using cannabis as teenagers, the drug may impair thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions. Researchers are still studying how long cannabis's effects last and whether some changes may be permanent. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

Cannabis has been shown to diminish academic and athletic performances and cause confusion. Studies with rats show that THC disrupts the normal functioning of the hippocampus, a part of the brain involved with memory. A study from New Zealand conducted in part by researchers at Duke University showed that people who started smoking cannabis heavily in their teens and had an ongoing cannabis use disorder lost an average of 8 IQ points between ages 13 and 38. The lost mental abilities didn't fully return in those who quit cannabis as adults. Those who started smoking cannabis as adults didn't show notable IQ declines.

In another recent study on twins, those who used cannabis showed a significant decline in general knowledge and in verbal ability (equivalent to 4 IQ points) between the preteen years and early adulthood, but no predictable difference was found between twins when one used cannabis and the other didn't. This suggests that the IQ decline in cannabis users may be caused by something other than cannabis, such as shared familial factors (e.g., genetics, family environment).6 NIDA’s Adolescent Brain Cognitive Development (ABCD) study, a major longitudinal study, is tracking a large sample of young Americans from late childhood to early adulthood to help clarify how and to what extent cannabis and other substances, alone and in combination, affect adolescent brain development.

Cannabis causes changes in brain chemistry and hinders some chemicals that relay signals in the nervous system. A 2002 study in the Journal of the American Medical Association showed that near-daily cannabis users scored more poorly on cognitive test and showed worse memories and attention spans than non users. In a study on how drugs affect the mind certain illegal drugs were injected into spiders to see how their webs would turn out. When spiders was given tranquilizers and cannabis their webs were smaller.

In recent years there has been an increased number of reports of psychosis and schizophrenia associated with cannabis, which have inluded delusions and hallucinations and required trips to the emergency room. While THC has been linked to psychotic reactions another chemical in cannabis — cannabisidiol — dampens these psychotic affects. One explanation for the recent reports is that new potent forms of cannabis have high concentrations of THC and lower doses of cannabisidiol. Emergency room responders have seen an increasing number of cases involving cannabis edibles. Some people (especially preteens and teens) who know very little about edibles don't realize that it takes longer for the body to feel cannabis’s effects when eaten rather than smoked. So they consume more of the edible, trying to get high faster or thinking they haven't taken enough. In addition, some babies and toddlers have been seriously ill after ingesting cannabis or marijuana edibles left around the house. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, December 2019]

Cannabis and Driving

Cannabis significantly impairs judgment, motor coordination, and reaction time, and studies have found a direct relationship between blood THC concentration and impaired driving ability. Cannabis is the illicit drug most frequently found in the blood of drivers who have been involved in vehicle crashes, including fatal ones. Two large European studies found that drivers with THC in their blood were roughly twice as likely to be culpable for a fatal crash than drivers who had not used drugs or alcohol. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, July 2020]

However, the role played by cannabis in crashes is often unclear because it can be detected in body fluids for days or even weeks after intoxication and because people frequently combine it with alcohol. Those involved in vehicle crashes with THC in their blood, particularly higher levels, are three to seven times more likely to be responsible for the incident than drivers who had not used drugs or alcohol. The risk associated with cannabis in combination with alcohol appears to be greater than that for either drug by itself.

Several meta-analyses of multiple studies found that the risk of being involved in a crash significantly increased after cannabis use — in a few cases, the risk doubled or more than doubled. However, a large case-control study conducted by the National Highway Traffic Safety Administration found no significant increased crash risk attributable to cannabis after controlling for drivers’ age, gender, race, and presence of alcohol.

Cannabis Use Disorder Becomes Addiction

Cannabis use can lead to the development of problem use, known as a cannabis use disorder, which takes the form of addiction in severe cases. Recent data suggest that 30 percent of those who use cannabis may have some degree of cannabis use disorder.18 People who begin using cannabis before the age of 18 are four to seven times more likely to develop a cannabis use disorder than adults. In 2015, about 4.0 million people in the United States met the diagnostic criteria for a cannabis use disorder;3 138,000 voluntarily sought treatment for their cannabis use. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, July 2020]

Cannabis use disorders are often associated with dependence — in which a person feels withdrawal symptoms when not taking the drug. People who use cannabis frequently often report irritability, mood and sleep difficulties, decreased appetite, cravings, restlessness, and/or various forms of physical discomfort that peak within the first week after quitting and last up to two weeks. Cannabis dependence occurs when the brain adapts to large amounts of the drug by reducing production of and sensitivity to its own endocannabinoid neurotransmitters.

Cannabis use disorder becomes addiction when the person cannot stop using the drug even though it interferes with many aspects of his or her life. Estimates of the number of people addicted to cannabis are controversial, in part because epidemiological studies of substance use often use dependence as a proxy for addiction even though it is possible to be dependent without being addicted. Those studies suggest that 9 percent of people who use cannabis will become dependent on it,24,25 rising to about 17 percent in those who start using in their teens.

Rising THC Potency

Cannabis potency, as detected in confiscated samples, has steadily increased over the past few decades. In the early 1990s, the average THC content in confiscated cannabis samples was less than 4 percent. In 2018, it was more than 15 percent. Cannabis concentrates can have much higher levels of THC. The increasing potency of cannabis, combined with the use of high-THC concentrates, raises concerns that the consequences of cannabis use today could be worse than in the past, particularly among those who are new to cannabis use and in young people, whose brains are still developing. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, July 2020]

Researchers do not yet know the full extent of the consequences when the body and brain (especially the developing brain) are exposed to high concentrations of THC or whether the recent increases in emergency department visits by people testing positive for cannabis are related to rising potency. The extent to which people adjust for increased potency by using less or by smoking it differently is also unknown. Recent studies suggest that experienced people may adjust the amount they smoke and how much they inhale based on the believed strength of the cannabis they are using, but they are not able to fully compensate for variations in potency.

According to the UNODC: Δ9-THC in cannabis herb seized increased fourfold in the United States between 1995 and 2018 and almost doubled in Europe between 2002 and 2018. Moreover, in some jurisdictions in Canada and the United States, other cannabis products, such as cannabis concentrates and edibles, may have a potency of 70 per cent or more,53 making the substance more potent and its users more prone to health consequences. Despite that trend, over that same period of time, the percentage of adolescents who consider regular use of cannabis to be harmful has significantly declined. As the scientific literature suggests, daily cannabis use has been associated with a greater likelihood of psychotic disorders among users than among people who have never used cannabis, and the likelihood of such disorders is nearly five times greater among those who, on a daily basis, use cannabis with a high Δ-9-THC content (Δ-9-THC, more than 10 per cent). [Source: United Nations Office on Drugs and Crime (UNODC), World Drug Report 2021]

Is Cannabis That Bad?

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Cannabis brain
No known person has ever died of a cannabis overdose. It is less toxic than many common foods. There is no evidence that cannabis is seriously psychologically or physically addictive. Only 9 percent of users developed a dependency and show withdrawal symptoms when they quit. Studies however indicate that heavy users who give up the habit suffer form anxiety and loss of appetite. People who were heavy users in their teens and 20s generally give up the drug by the time they are 30. Few remain heavy users into their 40s. .

A World Health Organization study released in February, 1997 determined that cannabis was safer than alcohol or tobacco. The findings had previously been suppressed due to political pressure. An editorial in Lancet, Britain's most respected medical journal, called for the legalization of cannabis. It asserted that "the smoking of cannabis, even long-term, is not harmful to health? and it “would be reasonable to judge cannabis less of a threat than alcohol or tobacco.”

Some people say that smoking the modern, more-potent versions of cannabis is more dangerous than the less potent versions in the old days. Some say this argument is a red herring because smokers today smoke less of the drug than people did in the 1960s and 70s.

In a study by a team led by Prof. David Nutt of Britain’s Bristol University published in the British medical journal Lancet, alcohol and tobacco were ranked as worse than cannabis and ecstasy using a ranking system that took into consideration physical harms caused by a substance, the potential for addiction and cost to society from its use. In the study heroin and cocaine ranked as the most dangerous drugs followed by barbiturates and street methadone. Alcohol was listed as the fifth most harmful drug with tobacco coming in ninth. Cannabis was 11th.

Medical Use of Cannabis

Nora D. Volkow, M.D., Director of National Institute on Drug Abuse wrote: Whether smoking or otherwise consuming cannabis has therapeutic benefits that outweigh its health risks is still an open question that science has not resolved. Although many states now permit dispensing cannabis for medicinal purposes and there is mounting anecdotal evidence for the efficacy of cannabis-derived compounds, the U.S. Food and Drug Administration has not approved "medical cannabis." However, safe medicines based on cannabinoid chemicals derived from the cannabis plant have been available for decades and more are being developed. [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, July 2020]

Cannabis is used to relieve the nausea and pain suffered by cancer patients undergoing chemotherapy. It also reduces the "wasting syndrome" in AIDS patients by stimulating appetite. Other drugs work better than cannabis in treating the nausea from chemotherapy but cannabis works well when patients don't respond to the normal treatments.

Cannabis is used treat the symptoms of arthritis, epilepsy, strokes, asthma, alcoholism. insomnia, and Alzheimer disease. It also helps slow the advance of glaucoma, and is used to treat the symptoms of multiple sclerosis and helps control multiple sclerosis spasms and tremors. Some multiple sclerosis patients say that cannabis use has brought feeling back to their legs and stopped chronic joint pain. It is also used by paraplegics.

A 1999 report by the independent Institute of Medicine (IOM), commissioned by the White House Office of National Drug Control Policy backed the medical uses of cannabis. Studies have shown that ingredients from cannabis could produce promising drugs for pain control; it may slow artery disease and prevent hardening of the arteries; and is already, surprisingly enough, is the source of chemical that are the key ingredient in new obesity-fighting oils. . Animals studies have shown that cannabinoids are a effective as codeine in treating mild to moderate pain. Cannabinoids act on a different set of brain receptors than opiates such as morphine.

Chemicals in cannabis have shown promise as bacteria fighters and as a schizophrenia drug. The antibacterial properties of THC have been known since the 1950s. Recent research by Giovanni Appendino of the University of the Eastern Piedmont indicates THC and other cannabisoids are particularly effective against microbial agents already resistant to several classes of drugs. While THC has been linked to psychotic reactions another chemical in cannabis — cannabisidiol — dampened these psychotic affects and has been used on psychiatric hospitals on psychotic patients with fewer side effects than widely-prescribed anti-psychotic drugs.

According to RTT News: “Cannabidiol or CBD is also a naturally-occurring cannabinoid constituent of cannabis. It is a chemical in the cannabis plant often used for medicinal purposes, and does not have the intoxicating effects like those caused by THC As CBD is believed to relieve or ease symptoms related to health problems, CBD-infused products such as beer, iced tea, jelly beans and ice cream are flooding the market. The CBD industry is expected to be a $20 billion industry by 2022.” [Source: RTT News]

Legalization of Cannabis

Cannabis has now been legalized for medical and recreational purpose in some countries. Uruguay and Canada are the only two countries that have fully legalized the consumption and sale of recreational cannabis nationwide. The U.S. states where recreational marijuana is legal (as of 2022) are: Colorado, Washington, Alaska, Oregon, Washington, D.C., California, Maine, Massachusetts, Nevada, Michigan, Vermont, Guam, Illinois, Arizona, Montana, New Jersey, New York, Virginia, New Mexico and Connecticut

In a 2002 survey in the U.S., about 80 percent of the people asked said they though cannabis should be legal for medical purpose and 72 percent agreed that people arrested for possessing small amounts of cannabis should be fined not jailed. At that time several of states allowed medical the use of cannabis Among those who have long supported legalizing cannabis outright are the billionaire philanthropist George Soros and the country singer Willie Nelson.

Nora D. Volkow, M.D., Director of National Institute on Drug Abuse wrote: Changes in cannabis policies across states legalizing cannabis for medical and/or recreational use suggest that cannabis is gaining greater acceptance in our society. Thus, it is particularly important for people to understand what is known about both the adverse health effects and the potential therapeutic benefits linked to cannabis.” [Source: National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services, July 2020]

Cannabis Busts

In one drug bust in Texas, a truck was found with 502 bales of cannabis, weighing 10 tons and worth $25 million.

In 2005, a suspected 51-year-old Australian drug smuggler died in southern Thailand when 60 hashish-packed condoms he swallowed burst in his body, and badly affected his colon and liver.

In 1994, U.S. Customs seized 559,286 pounds of marijuana. Officials believe, at most, this represents 10 percent of the cannabis entering the United States and does not include the cannabis that is produced domestically.

The greatest drug haul in terns of bulk of all time was the seizure of 3,200 tons of Columbian marijuana over 14 months by the United States Drug Enforcement Administration in 1982.

Image Source: DEA (Drug Enforcement Administration); Wikimedia Commons

Text Sources: 1) “Buzzed, the Straight Facts About the Most Used and Abused Drugs from Alcohol to Ecstasy” by Cynthia Kuhn, Ph.D., Scott Swartzwelder Ph.D., Wilkie Wilson Ph.D., Duke University Medical Center (W.W. Norton, New York, 2003); 2) National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services; 3) United Nations Office on Drugs and Crime (UNODC) and 4) National Geographic, New York Times, Washington Post, Los Angeles Times, Wikipedia, The Independent, Times of London, The New Yorker, Time, Newsweek, Reuters, Associated Press, AFP, , Lonely Planet Guides, and various books and other publications.

Last updated April 2022

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