What Is Marijuana?
What Is Marijuana?
Marijuana has a long history in human civilization. The plants, from which the fiber hemp and the drug marijuana come, have been grown all over the world for thousands of years. Humans have found many uses for this plant, but it is its use as a drug that makes it controversial and illegal in most countries.
Marijuana Is a Drug
Drug is a medical term that describes any substance that affects the functioning of living creatures. By this broad definition many common substances contain drugs, including coffee (caffeine), beer (ethyl alcohol), cigarettes (nicotine), cough medicine (codeine and other drugs), chocolate (theobromine and caffeine), and turkey (tryptophan). The thousands of substances created and sold by pharmacological companies with the intent of treating the medical diseases and conditions of humans and animals are drugs. Hundreds of medicinal herbs used for millennia by the world's physicians to treat, cure, and prevent disease are drugs. Most of these naturally occurring drugs, however, have been replaced with synthetic pharmaceutical drugs, which are usually more effective and more profitable than herbs.
In addition to the drugs used for medical treatment, many legal and illegal drugs are used to create feelings of pleasure, excitement, sleepiness, sleeplessness, and other sensations. Such drugs that affect the mind or behavior of the user are often termed psychotropic, which means the drug moves toward the mind rather than other parts of the body. This group includes marijuana as well as ethyl alcohol, nicotine, heroin, cocaine, methamphetamines, hallucinogens, and many other substances.
Although most drugs have legitimate medical purposes, many people use psychotropic drugs to get "high," which means to feel one or more nonmedical drug effects like pleasure, excitement, sleepiness, and sleeplessness. In addition, many people also use drugs that have genuine medical value for getting high. Excessive or nonmedical use of drugs is often described as drug abuse.
Drugs that have medical value are listed in a special type of catalog called a pharmacopoeia. Marijuana has been considered a medicinal drug throughout most of human history and has been listed in most pharmacopoeias until recently. In fact, the oldest known pharmacopoeia, a nearly four-thousand-year-old stone tablet from ancient Babylon, lists marijuana. Almost as old, a Chinese book on medical drugs called the Shen-nung Pen-tshao Ching describes marijuana's ability to reduce the pain of rheumatism and certain digestive disorders. Marijuana was listed in the United States Pharmacopoeia until 1941, when it was removed following the passage of the Marihuana Tax Act, which prohibited doctors from prescribing it.
Drugs cause a great variety of effects in humans and animals. Some of the effects can make drugs difficult or dangerous to use even when they have medically important properties. Two of these effects are called dependence and tolerance. These effects make drugs like morphine, a troublesome medication that requires careful management by a physician, one of the strongest painkillers known to medicine.
Dependence means that a person's body chemistry responds to a drug by developing the need to continue taking it to avoid unpleasant, painful, or even deadly reactions; in addition to whatever else a dependence-causing drug does (for example, kill pain, relieve fever, make a person high), it also produces extremely undesirable effects when the person tries to stop using it. These effects, called withdrawal symptoms, include breathing difficulty, muscle and joint pain, headaches, irritability, nausea, sweating, hallucinations, sleeplessness, psychosis, and, in the worst cases, death. When a drug causes severe dependence, meaning that the withdrawal symptoms themselves are severe, it is said to be addictive. Two of the most powerfully addictive drugs are nicotine, found in tobacco products, and opiates, found in heroin and morphine. Whether or not marijuana is addictive is a matter of disagreement, but it does cause mild withdrawal symptoms in a small percentage of users.
The likelihood of developing dependence increases if a drug causes tolerance. Tolerance describes the need to take ever-increasing amounts of the drug to obtain the same effect that a small dose once provided. As users begin taking such a drug more often, larger quantities of the drug are needed to achieve the same effect and to avoid unpleasant withdrawal symptoms. In most cases a drug that causes dependence, tolerance, and withdrawal is considered unsafe for human use.
The federal government's Food and Drug Administration (FDA) has the job of approving the safety of food and drugs. Drugs that the FDA determines to have little or no medical value and a high likelihood of being abused—not always with full agreement from the medical and scientific experts—are generally illegal to use, buy, or sell under any circumstances except for rigidly controlled research purposes. Some drugs currently judged by the FDA to have no medical value include heroin, lysergic acid diethylamide (LSD), and, since 1937, marijuana.
Source and Appearance of Marijuana
Marijuana comes from the flowering tops and leaves of two closely related species of plants known by the scientific names Cannabis sativa and Cannabis indica. Both species also produce the fiber known as hemp that is used for rope and fabric. In fact, the marijuana plant itself is often called hemp because its fiber has been so important throughout history.
With such a long history of cultivation, many varieties of cannabis plants have developed so that today cannabis is grown in almost all climates. All it needs is lots of sunshine, soil, and water; so besides intentional cultivation, it sometimes also grows wild. Law enforcement agencies have discovered wild and cultivated marijuana growing in places as diverse as Alaska, Hawaii, Switzerland, Brazil, and Africa.
Marijuana is usually a green, brown, or gray mixture of dried leaves, stems, flowers, and seeds from the cannabis plant. Marijuana might come as a crumbly brown mixture of dried material resembling the common kitchen spice oregano. Or it can appear as a pressed mass of light green vegetable matter. In its dry form, it can have a very strong fragrance, often musty or spicy, or almost no smell at all.
Hashish, often called simply hash, is a form of marijuana that is popular in Europe and Asia. It is an aromatic, solid material made by collecting the resin droplets that coat the leaves and flowers of mature cannabis plants and pressing them into patties of hashish. One of the most potent forms of cannabis is a thick green or black oil,
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known as marijuana oil or hash oil, that is made by cooking marijuana or hashish in alcohol to concentrate the active ingredient.
Different Names and Forms
With a long history of cultivation by many different civilizations, it comes as no surprise that there are a great number of words for marijuana (sometimes spelled marihuana). Marijuana, a Spanish word, is one of the most common names for the drug, but many people in medicine and research now refer to marijuana as cannabis (KAN-nahbiss), which is part of the scientific name for the plant from which marijuana is derived. The term cannabis is also used increasingly by journalists in newspaper and magazine articles in place of marijuana.
Although cannabis is now the name preferred by many scientists, political leaders, and medical professionals, there is a large vocabulary of popular-slang, and underground terms for marijuana. Some of the more common terms for this drug in the United States include pot, dope, weed, herb, grass, bud, Mary Jane, reefer, hydro (refers to marijuana grown in nutrient-rich water without soil), pakalolo (Hawaii), and smoke. Terms from other cultures for marijuana include hashish (Asia), ganja (India, Caribbean), kif (Morocco), sinsemilla (Latin America), mota (Mexico), dagga (South Africa), bhang (India), and macoinha (Brazil).
Hemp, Marijuana's "Good" Side
Cannabis plants have been grown for hemp fiber for thousands of years. Hemp was grown in all of the American colonies before and after independence and formed a valuable raw material throughout American history until the end of World War II. The varieties of cannabis plants used for fiber contain only small amounts of the psychotropic ingredients found in the varieties that produce marijuana.
Even though industrial hemp is illegal to grow in the United States today, in 1994 the American Farm Bureau Federation described it as a strong and versatile agricultural crop cultivated in many other countries. Currently, hemp is grown legally throughout much of Europe and Asia, and Australia and Canada are both considering legalizing industrial hemp farming. In France, for instance, where approximately ten thousand tons of industrial hemp are harvested annually, bales of hemp hay coated with cement are used to restore and build houses and walls. Various parts of the plant can also be used to make textiles, paper, paints, clothing, plastics, cosmetics, foodstuffs, insulation, and animal feed. Hemp produces a higher yield of fiber per acre than cotton and other fiber-producing plants. In addition, hemp has an average growing cycle of only a hundred days, and after harvest the soil is left virtually weed-free for the next planting.
The Chemistry and Action of Marijuana
The components of marijuana that create both the drug's high and its medicinal effects belong to a family of chemicals called cannabinoids. Marijuana contains more than sixty different cannabinoids, all found only in the cannabis plant. Furthermore, when marijuana is heated or burned, chemical changes occur that increase the number of cannabinoids and their derivatives. The resulting large number of chemicals interact in complex ways. This is one of the reasons marijuana is so difficult to study.
The most psychotropic of the cannabinoids is the compound delta-9-tetrahydrocannabinol, usually shortened to THC. Dried marijuana may contain anywhere from 2 to 20 percent THC, with the average being 4.2 percent.
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The amount of THC in marijuana determines its potency as a drug. The leaves of industrial hemp cannabis have very low THC content (less than 1 percent of the dry weight) while the flowering tips of mature female marijuana plants have a higher concentration of THC (varying between 2 percent and 20 percent of the dry weight).
What Purpose Does THC Serve in the Plant?
The fact that THC produces an effect on the human brain is an accidental outcome of a complex chemistry that serves other purposes for the plant. Scientists are still researching the value of cannabinoids to the plant, but it appears certain that these substances are important to the plant's survival. Because of the complex structure of the cannabinoid compounds and the resin glands that produce them, scientists do not believe that THC and other cannabinoids are merely by-products or waste products of the plant's metabolism. Instead, cannabinoids appear to be used by the plant for a number of purposes, most having to do with protecting the plant from predators and helping it reproduce successfully.
Most scientists now believe that the primary purpose of these complex and biologically active compounds is to protect the plant from other organisms. The fragrance and taste of the cannabinoids that coat the leaves and flowers seem to discourage insects and plant-eating animals from consuming the cannabis plants before they have produced seeds.
Cannabinoids also appear to play another important role in the plant's biological success. Scientists have found evidence that cannabinoids released into the soil help the plant compete for growing room by chemically discouraging the seeds of other species from germinating too close to a cannabis plant. The sticky nature of cannabinoid resins may also help pollen grains from male plants adhere to the flowering parts of the female plants.
When THC is consumed, either by smoking or ingesting marijuana, the human body reacts in a number of ways. Peak levels of THC in the blood usually occur within ten minutes of smoking marijuana, and intoxication lasts approximately two to three hours. Because it dissolves poorly in water and very well in fat (lipids), THC and other cannabinoids accumulate in the body's fatty tissues, including the brain and testes. Since cannabinoids and their breakdown product, called metabolites, linger in these tissues for weeks and sometimes even months, drug tests can appear positive for cannabinoid compounds for a long time after using marijuana.
Scientific research during the 1990s made great strides in understanding how THC and other cannabinoids act in the human body. One of the most important findings of this research was the discovery that the brain and other parts of the body contain cannabinoid receptor sites, places where cannabinoids can change the chemistry of that region. (Researchers also found natural cannabinoids in the human body, which explains why the body has cannabinoid receptor sites in the first place.)
In the part of the human brain known as the hippocampus, scientists found large numbers of cannabinoid receptors. It is here they believe THC produces the marijuana high. When THC attaches to the abundant cannabinoid receptors found in the hippocampus, it causes the brain to suffer a partial loss of short-term memory. The hippocampus interacts with other brain regions to transfer new information, like a math lesson or friend's phone number, from short-term memory into long-term memory. Consequently, new information may never register in long-term memory while the brain is under the influence of marijuana.
Marijuana's effects are not limited to the hippocampus, however. Besides making a person high and interfering with memory, marijuana can cause some people to experience uncontrollable laughter one minute and paranoia the next. These effects are due to cannabinoid receptors in another part of the brain, the limbic system, where emotions are produced.
How Is Marijuana Consumed?
To produce its effects, molecules of marijuana's active ingredients (especially the THC) need to reach the brain through the bloodstream. This is accomplished by smoking or ingesting (eating or drinking) marijuana.
Marijuana is smoked far more often than it is eaten, however. The primary reason for this is that smoking produces the high almost immediately while eating it takes anywhere from thirty minutes to an hour. Marijuana is typically smoked in a hand-rolled cigarette called a joint or in any of a variety of pipes. A type of pipe that delivers a particularly large amount of smoke during each inhalation is called a bong.
Another reason smoking marijuana is more widely practiced than eating it is that smoking allows for more precise dose control. When the drug is smoked, users can tell almost at once if they have taken in enough for the desired effect. With eating, it can be an hour before users can tell if they have too much or too little THC in their bloodstream.
Effects of Marijuana
Consuming marijuana causes a number of effects on the user. In a social setting, marijuana may cause infectious laughter and talkativeness. In addition, short-term memory, attention, coordination, and reaction time are impaired while a person is under the influence of marijuana. Soon after smoking marijuana, a user also usually has bloodshot
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eyes and a dry mouth. And, within a few hours of smoking marijuana, most users become sleepy.
The total set of effects, however, varies from person to person. Further, the same person can experience different effects depending on how strong the marijuana is, his or her mood while using it, where the drug is used, and whether or not other drugs (including alcohol) are being used at the same time.
The most commonly reported unpleasant side effects of occasional marijuana use are anxiety and panic. These effects are reported more often by inexperienced users, and these unpleasant feelings are often the reason new users stop taking the drug. More experienced users also have reported feelings of anxiety and panic after receiving a much larger than usual dose of THC.
One reason marijuana causes anxiety is that it can increase the user's heart rate by 20 to 50 percent within about ten minutes of smoking it and about half an hour of eating it. This elevated heart rate, which can continue for as long as three hours, may be accompanied by a slight increase in blood pressure while the user is sitting and a slight decrease when standing. The light-headedness that can result from this may also intensify the user's feeling of anxiety. Despite this group of effects, cannabinoids are not considered especially toxic and there are no confirmed reports worldwide of human deaths from cannabis poisoning.
Nevertheless, marijuana, like tobacco and alcohol, has the potential to cause permanent harm to children if used by their mothers during pregnancy. Although there is considerable disagreement among scientists and doctors as to the severity of the problem, there is evidence that low birth weight and physical abnormalities have occurred among babies whose mothers used the drug during pregnancy.
There is stronger evidence that marijuana use has a negative impact on athletic performance, a result of research showing impairments in coordination, reaction time, and concentration caused by marijuana. Furthermore, some studies have found that athletic performance might be impaired for as long as twenty-four hours after marijuana use.
Marijuana's Effect on the Heart and Lungs
The increased heart rate associated with marijuana use can cause other problems. A 1999 report on medical marijuana from the U.S. government's Institute of Medicine (IOM) noted that even though the elevated heart rate experienced by marijuana users is not considered excessive for people in good health, among those with heart disease, such a rise in heart rate could be fatal.
In such cases, marijuana smokers with unidentified heart disease may be vulnerable, especially during the first hour after smoking, to an increased risk of heart attack. In a 2000 report from the American Heart Association (AHA), researchers questioned 3,882 middle-aged and elderly patients who had suffered heart attacks. Of that group, 124 admitted to being current marijuana users, 37 had used the drug in the twenty-four hours preceding their heart attacks, and 9 had used it in the hour before. The AHA pointed out that this was the first time science had found evidence that marijuana might trigger a heart attack in susceptible individuals. The report concluded that among this age group the risk of having a heart attack during the first hour after smoking marijuana is five times greater than it is in people who never use the drug.
The AHA report also stated that the cardiac risks from marijuana appear to be much lower than those from cocaine, which causes a much sharper rise in both heart rate and blood pressure than marijuana. The overall public health threat from marijuana, however, could be even greater because marijuana use is more widespread than cocaine use.
Other studies conducted by government and other research facilities contend that the only proven long-term effects of marijuana use are all related to risks posed by smoking. Users usually inhale marijuana smoke deeply and hold the smoke in their lungs for at least several seconds. Marijuana smoke contains tar, carbon monoxide, and many complex chemicals, almost all of which are respiratory irritants and potential cancer-causing agents. In fact, according to the IOM report, each inhalation of marijuana smoke contains three to five times more tar and carbon monoxide than an equal amount of tobacco smoke. Therefore, a person who smokes marijuana daily for years might face the same respiratory problems as a tobacco smoker. These individuals may cough more often, produce more phlegm, show symptoms of chronic bronchitis, and have more frequent chest colds. Long-term smoking of marijuana can also damage lung tissues and make breathing difficult. The reason marijuana smokers do not
Who Smokes Pot?
Many people have stereotypical views of who uses marijuana. Some people want to change the image of marijuana users. In the June 28, 2001, issue of NORML News, an article entitled "We're Your Good Neighbors. We Smoke Pot" provides some examples of ordinary citizens "coming out" about their marijuana use.
Near Portland, Oregon, a June 2001 full-page advertisement in the Willamette Week newspaper had folks scratching their heads. At the top of the advertisement was the headline "We're Jeff and Tracy. We're your good neighbors. We smoke pot."
Jeff Jarvis and Tracy Johnson, the Oregon couple who ran the advertisement, are calling on mainstream Americans to come out of the closet regarding their use of marijuana and show people that marijuana smokers are not a threat to society. Their ad read, "The United States government acknowledges that over 70 million American adults have smoked pot. That's one in three of your neighborhood doctors, grocers, college professors, police officers, computer programmers, postal carriers, engineers, business executives, and spiritual leaders. These pot smokers are your elected officials. They are your dearest friends. They are your family members."
The Oregon couple are part of a growing movement to "come out of the closet" about marijuana use. Mara Leveritt, senior editor for the Arkansas Times, took this movement one step further by publicly admitting her use of marijuana in an op-ed column that appeared in her newspaper in the spring of 1995. She wrote:
For the past two decades, I have smoked, on average, about a joint a day. . . . If long-term, regular users like myself felt free to articulate their experiences with marijuana, the walking, talking evidence we'd represent could put our marijuana laws to shame. We may not all be intellectual and moral paragons [models]. . . . On the other hand, few of us are wild-eyed marauders, genetic mutants, or drooling derelicts from whom society need protect itself. And as we get older, our lives begin to make the lies that have been broadcast about marijuana look even more ridiculous.
Leveritt and the couple from Oregon join many other marijuana advocates who want people to know that most cannabis users are responsible citizens. According to them, Americans don't have to be afraid that marijuana use is going to spread throughout society—because it already has.
commonly exhibit such health problems, according to the IOM report, is that they usually smoke much less than tobacco smokers.
Although many people consider marijuana to be a dangerous drug, and many studies confirm that users do indeed place themselves at risk for health problems, the extent of those problems and how much of a risk they pose remain controversial. Now a wave of new research is showing that marijuana is neither as dangerous to society and individuals as some previously believed or as entirely harmless as others have believed.
"What Is Marijuana?." Drug Education Library: Marijuana. . Encyclopedia.com. (April 19, 2019). https://www.encyclopedia.com/medicine/medical-magazines/what-marijuana
"What Is Marijuana?." Drug Education Library: Marijuana. . Retrieved April 19, 2019 from Encyclopedia.com: https://www.encyclopedia.com/medicine/medical-magazines/what-marijuana
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