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Definition

Marijuana (marihuana) Cannabis sativa L., also known as Indian hemp, is a member of the Cannabaceae or hemp family, thought to have originated in the mountainous districts of India, north of the Himalayan mountains.

Description

The herb was referred to as "hempe" in A.D. 1000 and listed in a dictionary under that English name. Supporters of the notorious Pancho Villa first used the name marijuana in 1895 in Sonora, Mexico. They called the mood-altering herb they smoked marijuana. The term hashish, is derived from the name for the Saracen soldiers, called hashashins, who ingested the highly potent cannabis resin before being sent out to assassinate enemies.

Two related species of cannabis are C. ruderalis, and C. indica, a variety known as Indian hemp. Indian hemp grows to a height of about 4 ft (1.2 m) and the seed coats have a marbled appearance.

The species C. sativa L. has many variations, depending on the soil, temperature, and light conditions, and the origin of the parent seed. These factors also affect the relative amounts of THC (tetra-hydrocannabinol) and cannabidiol, the chemicals present in varying amounts in cannabis that determine if the plant is primarily a fiber type or an intoxicant. Generally the species grown at higher elevations and in hotter climates exudes more of the resin and is more medicinally potent.

Marijuana is a somewhat weedy plant and may grow as high as 18 ft (5.4 m). The hairy leaves are arranged opposite one another on the erect and branching stem. Leaves are palmate and compound, deeply divided into five to seven narrow, toothed and pointed leaflets. Male and female flowers are small and greenish in color and grow on separate plants. Male flowers grow in the leaf axils in elongated clusters. The female flowers grow in spike-like clusters. The resinous blossoms have five sepals and five petals. The male and female blossoms can be distinguished at maturity. The male plant matures first, shedding its pollen and dying after flowering. Female plants die after dropping the mature seeds. Marijuana produces an abundance of quickly germinating seeds. This hardy annual is wind pollinated and has escaped from cultivation to grow wild along roadsides, trails, stream banks, and in wayside places throughout the world. The plant matures within three to five months after the seed has been sown.

Marijuana has been cultivated for thousands of years. Cannabis was first described for its therapeutic use in the first known Chinese pharmacopoeia, the Pen Ts'ao. (A pharmacopoeia is a book containing a list of medicinal drugs, and their descriptions of preparation and use.) Cannabis was called a "superior" herb by the Emperor Shen-Nung (2737–2697 B.C.), who is believed to have authored the work. Cannabis was recommended as a treatment for numerous common ailments. Around that same period in Egypt, cannabis was used as a treatment for sore eyes. The herb was used in India in cultural and religious ceremonies, and recorded in Sanskrit scriptural texts around 1,400 B.C. Cannabis was considered a holy herb and was characterized as the "soother of grief," "the sky flyer," and "the poor man's heaven." Centuries later, around 700 B.C., the Assyrian people used the herb they called Qunnabu, for incense. The ancient Greeks used cannabis as a remedy to treat inflammation, earache, and edema (swelling of a body part due to collection of fluids). Shortly after 500 B.C. the historian and geographer Herodotus recorded that the peoples known as Scythians used cannabis to produce fine linens. They called the herb kannabis and inhaled the "intoxicating vapor" that resulted when it was burned. By the year 100 B.C. the Chinese were using cannabis to make paper.

Cannabis use and cultivation migrated with the movement of various traders and travelers, and knowledge of the herb's value spread throughout the Middle East, Eastern Europe, and Africa. Around 100, Dioscorides, a surgeon in the Roman Legions under the Emperor Nero, named the herb Cannabis sativa and recorded numerous medicinal uses. In the second century, the Chinese physician Hoa-Tho used cannabis in surgical procedures, relying on its analgesic properties. In ancient India, around 600, Sanskrit writers recorded a recipe for "pills of gaiety," a combination of hemp and sugar. By 1150, Moslems were using cannabis fiber in Europe's first paper production. This use of cannabis as a durable and renewable source of paper fiber continued for the next 750 years.

By the 1300s, government and religious authorities, concerned about the psychoactive effects on citizens consuming the herb, were placing harsh restrictions on its use. The Emir Soudon Sheikhouni of Joneima outlawed cannabis use among the poor. He destroyed the crops and ordered that offenders' teeth be pulled out. In 1484, Pope Innocent VIII outlawed the use of hashish, a concentrated form of cannabis. Cannabis cultivation continued, however, because of its economic value. A little more than a century later, the English Queen Elizabeth I issued a decree commanding that landowners holding 60 acres or more must grow hemp or pay a fine. Commerce in hemp, which was primarily valued for the strength and versatility of its fibers, was profitable and thriving. Hemp ropes and sails were crossing the sea to North America with the explorers. By 1621, the British were growing cannabis in Virginia where cultivation of hemp was mandatory. In 1776, the Declaration of Independence was drafted on hemp paper. Both President George Washington and President Thomas Jefferson were advocates of hemp as a valuable cash crop. Jefferson urged farmers to grow the crop in lieu of tobacco. By the 1850s, hemp had become the third largest agricultural crop grown in North America. The U. S. Census of that year recorded 8,327 hemp plantations, each with 2,000 or more acres in cultivation. But the invention of the cotton gin was already bringing many changes, and cotton was becoming a prime and profitable textile fiber. More change came with the introduction of the sulfite and chlorine processes used to turn trees into paper. Restrictions on the personal use of cannabis as a mood-altering, psychoactive herb, were soon to come.

— Clare Hanrahan

1. The cannabis plant.
2. A preparation made from the dried flower clusters and leaves of the cannabis plant, usually smoked or eaten to induce euphoria.

[Spanish marihuana.]

The Spanish name for the dried leaves and flowering tops of the hemp plant, Cannabis sativa (Cannabinaceae). The narcotic ingredients allegedly have stimulating effects, and after smoking two or three cigarettes, the smoker often has a feeling of well-being and increased power and ability. After excessive amounts of the drug, illusions are often common, as well as pleasing, fanciful hallucinations. Sometimes the excessive user experiences disorientation and even delirium. See also Hemp.

A drug sometimes called cannabis or grass. It is obtained from the hemp plant Cannabis sativa, which contains the active ingredient tetrahydrocannabinol. The psychological effects of marijuana include sedation, relaxation, and euphoria. It may disturb the sense of balance and reduce aggression. Persistent marijuana smoking is incompatible with serious training because it tends to demotivate exercisers.

Many people argue that, compared to alcohol, marijuana is harmless and should be legalized. But its harmless nature has been seriously questioned recently. Chronic over-indulgence has been linked to a number of disorders and possible addiction.

Description

Marijuana (marihuana), Cannabis sativa L., also known as Indian hemp, is a member of the Cannabaceae or hemp family, thought to have originated in the mountainous districts of India, north of the Himalayan mountains. The herb was referred to as "hempe" in A.D. 1000 and listed in a dictionary under that English name. Supporters of the notorious Pancho Villa first called the mood-altering herb they smoked marijuana in 1895 in Sonora, Mexico. The term hashish, is derived from the name for the Saracen soldiers, called hashashins, who ingested the highly potent cannabis resin before being sent out to assassinate enemies.

Two related species of cannabis are C. ruderalis and C. indica, a variety known as Indian hemp. Indian hemp grows to a height of about 4 ft (1.2 m) and the seed coats have a marbled appearance.

The species C. sativa L. has many variations, depending on the origin of the parent seed and the soil, temperature, and light conditions. These factors also affect the relative amounts of THC (tetra-hydrocannabinol) and cannabidiol, the chemicals present in varying amounts in cannabis that determine if the plant is primarily a fiber type or an intoxicant. Generally the species grown at higher elevations and in hotter climates exudes more of the resin and is more medicinally potent.

Marijuana is a somewhat weedy plant and may grow as high as 18 ft (5.4 m). The hairy leaves are arranged opposite one another on the erect and branching stem. Leaves are palmate and compound, deeply divided into five to seven narrow, toothed and pointed leaflets. Male and female flowers are small and greenish in color and grow on separate plants. Male flowers grow in the leaf axils in elongated clusters. The female flowers grow in spike-like clusters. The resinous blossoms have five sepals and five petals. The male and female blossoms can be distinguished at maturity. The male plant matures first, shedding its pollen and dying after flowering. Female plants die after dropping the mature seeds. Marijuana produces an abundance of quickly germinating seeds. This hardy annual is wind pollinated and has escaped from cultivation to grow wild along roadsides, trails, stream banks, and in wayside places throughout the world. The plant matures within three to five months after the seed has been sown.

History

Marijuana has been cultivated for thousands of years. Cannabis was first described for its therapeutic use in the first known Chinese pharmacopoeia, the Pen Ts'ao. (A pharmacopoeia is a book containing a list of medicinal drugs, and their descriptions of preparation and use.) Cannabis was called a "superior" herb by the Emperor Shen-Nung (2737–2697 B.C.), who is believed to have authored the work. Cannabis was recommended as a treatment for numerous common ailments. Around that same period in Egypt, cannabis was used as a treatment for sore eyes. The herb was used in India in cultural and religious ceremonies, and recorded in Sanskrit scriptural texts around 1,400 B.C. Cannabis was considered a holy herb and was characterized as the "soother of grief," "the sky flyer," and "the poor man's heaven." Centuries later, around 700 B.C., the Assyrian people used the herb they called Qunnabu for incense. The ancient Greeks used cannabis as a remedy to treat inflammation, earache, and edema (swelling of a body part due to collection of fluids). Shortly after 500 B.C. the historian and geographer Herodotus recorded that the peoples known as Scythians used cannabis to produce fine linens. They called the herb kannabis and inhaled the "intoxicating vapor" that resulted when it was burned. By the year 100 B.C. the Chinese were using cannabis to make paper.

Cannabis use and cultivation migrated with the movement of various traders and travelers, and knowledge of the herb's value spread throughout the Middle East, Eastern Europe, and Africa. Around A.D. 100, Dioscorides, a surgeon in the Roman Legions under the Emperor Nero, named the herb Cannabis sativa and recorded numerous medicinal uses. In the second century, the Chinese physician Hoa-Tho, used cannabis in surgical procedures, relying on its analgesic properties. In ancient India, around 600, Sanskrit writers recorded a recipe for "pills of gaiety," a combination of hemp and sugar. By 1150, Moslems were using cannabis fiber in Europe's first paper production. This use of cannabis as a durable and renewable source of paper fiber continued for the next 750 years.

By the 1300s, government and religious authorities, concerned about the psychoactive effects on citizens consuming the herb, were placing harsh restrictions on its use. The Emir Soudon Sheikhouni of Joneima outlawed cannabis use among the poor. He destroyed the crops and ordered that offenders' teeth be pulled out. In 1484, Pope Innocent VIII outlawed the use of hashish, a concentrated form of cannabis. Cannabis cultivation continued, however, because of its economic value. A little more than a century later, the English Queen Elizabeth I issued a decree commanding that landowners holding 60 acres (24 ha) or more must grow hemp or pay a fine. Commerce in hemp, which was primarily valued for the strength and versatility of its fibers, was profitable and thriving. Hemp ropes and sails were crossing the sea to North America with the explorers. By 1621, the British were growing cannabis in Virginia where cultivation of hemp was mandatory. In 1776, the Declaration of Independence was drafted on hemp paper. Both President George Washington and President Thomas Jefferson were advocates of hemp as a valuable cash crop. Jefferson urged farmers to grow the crop in lieu of tobacco. By the 1850s, hemp had become the third largest agricultural crop grown in North America. The U.S. Census of that year recorded 8,327 hemp plantations, each with 2,000 or more acres in cultivation. But the invention of the cotton gin was already bringing many changes, and cotton was becoming a prime and profitable textile fiber. More change came with the introduction of the sulfite and chlorine processes used to turn trees into paper. Restrictions on the personal use of cannabis as a mood-altering, psychoactive herb, were soon to come.

Controversy

The 1856 edition of the Encyclopedia Britannica, in its lengthy entry on hemp, noted that the herb "produces inebriation and delirium of decidedly hilarious character, inducing violent laughter, jumping and dancing." This inebriating effect of marijuana use has fueled the controversy and led to restrictions that have surrounded marijuana use throughout history in many cultures and regions of the world. Cannabis use has been criminalized in some parts of the United States since 1915. Utah was the first state to criminalize it, then California and Texas. By 1923, Louisiana, Nevada, Oregon, and Washington had legal restrictions on the herb. New York prohibited cannabis use in 1927.

In 1937, the federal government passed the Marijuana Tax Act, prohibiting the cultivation and farming of marijuana. This bill was introduced to Congress by then Secretary of the Treasury Andrew Mellon, who was also a banker for the DuPont Corporation. That same year, the DuPont Chemical Company filed a patent for nylon, plastics, and a new bleaching process for paper. The 1937 Marijuana Transfer Tax Bill prohibited industrial and medical use of marijuana and classified the flowering tops as narcotic, and restrictions on the cultivation and use of cannabis continued. Marijuana was categorized as an illegal narcotic, in the company of LSD and heroin, cocaine, and morphine. Illegal use continued. The FBI publication, Uniform Crime Reports for The United States, 1966 reported that 641,642 Americans were arrested for marijuana offenses that year, with as many as 85% of these arrests for simple possession, rather than cultivation or commerce.

In a reversal of the state-by-state progression of criminalizing marijuana that led to the 1937 Marijuana Transfer Tax Bill, there is a movement underway, state by state, to endorse the legalized use of medical marijuana. By 1992, 35 states in the United States had endorsed referenda for medical marijuana. A growing body of scientific research and many thousands of years of folk use support the importance of medical marijuana in treatment of a variety of illnesses, and the economic value of hemp in the textile, paper, and cordage industries has a long history.

The controversy and misinformation persists around this relatively safe and non-toxic herb. The World Health Organization, in a 1998 study, stated that the risks from cannabis use were unlikely to seriously compare to the public health risks of the legal drugs, alcohol and tobacco. And despite thousands of years of human consumption, not one death has been directly attributed to cannabis use. According to Lester Grinspoon, MD, and James B. Bakalar, JD, in a 1995 Journal of the American Medical Association article, "Marijuana is also far less addictive and far less subject to abuse than many drugs now used as muscle relaxants, hypnotics, and analgesics. The chief legitimate concern is the effect of smoking on the lungs. Cannabis smoke carries even more tars and other particulate matter than tobacco smoke. But the amount smoked is much less, especially in medical use, and once marijuana is an openly recognized medicine, solutions may be found."

General Use

Every part of the cannabis plant, including buds, leaves, seeds, and root, has been utilized throughout the long history of this controversial herb. Despite persistent legal restrictions and severe criminal penalties for illicit use, marijuana continues to be widely used in the United States, and throughout the world, both for its mood-altering properties and its proven medicinal applications. The conflicting opinions on the safety and effectiveness of cannabis in a climate of prohibition make any discussion of its beneficial uses politically charged. Marijuana has analgesic, anti-emetic, anti-inflammatory, sedative, anti-convulsive, and laxative actions. Clinical studies have demonstrated its effectiveness in relieving nausea and vomiting following chemotherapy treatments for cancer. The herb has also been shown to reduce intraocular pressure in the eye by as much as 45%, a beneficial action in the treatment for glaucoma. Cannabis has proven anticonvulsive action, and may be helpful in treating epilepsy. Other research has documented an invitro tumor inhibiting effect of THC. Marijuana also increases appetite and reduces nausea and has been used with AIDS patients to counter weight loss and "wasting" that may result from the disease. Several chemical constituents of cannabis displayed antimicrobial action and antibacterial effects in research studies. The components CBC and d-9-tetra-hydrocannabinol have been shown to destroy and inhibit the growth of streptococci and staphylococci bacteria.

In 2002, the Dutch government announced that a small trial would begin in the country to study the effects of medical marijuana on patients with multiple sclerosis. After extending the number of participants in the trial, researchers also hoped to add patients with neuralgia and lower back pain to the study.

Cannabis contains chemical compounds known as cannabinoids. Different cannabinoids seem to exert different effects on the body after ingestion. Scientific research indicates that these substances have potential therapeutic value for pain relief, control of nausea and vomiting, and appetite stimulation. The primary active agent identified to date is 9-tetrahydrocannabinol, known as THC. This chemical may constitute as much as 12% of the active chemicals in the herb, and is said to be responsible for as much as 70–100% of the euphoric action, or "high," experienced when ingesting the herb. The predominance of this mental lightness or "euphoria" depends on the balance of other active ingredients and the freshness of the herb. THC degrades into a component known as cannabinol, or CBN. This relatively inactive chemical predominates in marijuana that has been stored too long prior to use. Another chemical component, cannabidiol, known as CBD, has a sedative and mildly analgesic effect, and contributes to a somatic heaviness sometimes experienced by marijuana users.

Before prohibition, cannabis was recommended for treatment of gonorrhea, angina pectoris (constricting pain in the chest due to insufficient blood to the heart), and choking fits. It was also used for insomnia, neuralgia, rheumatism, gastrointestinal disorders, cholera, tetanus, epilepsy, strychnine poisoning, bronchitis, whooping cough, and asthma. Other phytotherapeutic (plant-based therapeutic) uses include treatment of ulcers, cancer, emphysema, migraine, and anxiety.

The United States federal government policy prohibits physicians from prescribing marijuana, even for seriously ill patients because of possible adverse effects, and the disputed belief that cannabis is dangerously addictive. Former U.S. Attorney General Janet Reno warned that physicians in any state who prescribed marijuana could lose the privilege of writing prescriptions, be excluded from Medicare and Medicaid reimbursement, and even be prosecuted for a federal crime, according to a 1997 editorial in the New England Journal of Medicine. Yet in 1996, California passed a law legalizing medical use of marijuana and many other states have introduced similar laws. The debate in the United States over medical use of the drug continues. Some opponents believe that the movement to legalize marijuana for medicinal purposes is led by those who want the drug legalized for recreational purposes.

Preparations

Cannabis extracts, prepared for medicinal application, are prohibited in the United States. Marijuana is ingested by smoking, which quickly delivers the active ingredients to the blood system. The dried herb is also variously prepared for eating. The essential oil consists of beta caryophyllenes, humules, caryophyllene oxide, alpha-pinenes, beta-pinenes, limonene, myrcene, and betaocimene. The oil expressed from the seeds is used for massage and in making salves used to relieve muscle strain.

Precautions

Marijauna is considered a Class I narcotic and its use has been restricted by federal law since 1937. Penalties include fines and imprisonment. The National Commission on Marihuana and Drug Abuse concluded in 1972 that, "A careful search of the literature and testimony of the nation's health officials has not revealed a single human fatality in the United States proven to have resulted solely from ingestion of marihuana."

Research has shown that cannabis acts to increase heart frequency by as much as 40 beats per minute. A study reported by The American Heart Association in February 2000, concluded that smoking marijuana can precipitate a heart attack in persons with pre-existing heart conditions. One hour after smoking marijuana, the likelihood of having a heart attack is four and one-half times greater than if the person had not smoked, according to the research. A 2002 report cautioned that marijuana use during pregnancy cuts the child's birth weight, a possible indication of problems for the unborn child. Early results indicate that pregnant women should avoid using marijuana.

An additional health concern is the effect that marijuana smoking has on the lungs. Cannabis smoke carries more tars and other particulate matter than tobacco smoke.

Side Effects

The PDR For Herbal Medicine reports, "No health hazards or side effects are known in conjunction with the proper administration of designated therapeutic dosages." Smoking the herb, however, "leads almost at once to euphoric states (pronounced gaiety, laughing fits)," and "long term usage leads to a clear increase in tolerance for most of the pharmacological effects." The ability to safely operate automobiles and machinery can be impaired for up to eight hours after ingesting the herb. Chronic abuse results in "laryngitis, bronchitis, apathy, psychic decline and disturbances of genital functions," according to the PDR. In early 2002, several published studies showed conflicting results about the effects of long-term chronic use of marijuana on memory and cognitive function. For the most part, however, these effects seem to lessen after use is halted. Further research on the effects of marijuana on memory and how long those effects may last should continue.

Some people may be hypersensitive to marijuana. They may experience paranoia or be allergic or sensitive to the plant. Chronic sinus fungal infections have been linked to chronic marijuana smoking.

Interactions

Marijauna use may mask the perceived effects of alcohol and cocaine when the drugs are consumed together. Marijuana is said to exert a synergistic effect with other medicinal agents. When used with nitrous oxide it may enhance the effect.

Resources

Books

Foster, Steven, and James A. Duke. Peterson Field Guides, Eastern/Central Medicinal Plants. Boston-New York: Houghton Mifflin Company, 1990.

Lust, John. The Herb Book. New York: Bantam Books, 1974.

Magic and Medicine of Plants. The Reader's Digest Association, Inc. 1986.

PDR for Herbal Medicines. New Jersey: Medical Economics Company, 1998.

Periodicals

Eidelman, William S., and Eric A. Voth. "Should Physicians Support the Medical Use of Marijuana?" The Western Journal of Medicine 176, no. 2 (March 2002): 76.

Grinspoon, Lester, M.D., and James B. Bakalar, JD. The Journal of the American Medical Association 273, No. 23 (June 21, 1995): 1875–1876.

Kassirer, Jerome P., M.D. "Federal Foolishness and Marijuana." Massachusetts Medical Society, New England Journal of Medicine 336, no. 5 (January 30, 1997): 366–367.

"Marijuana During Pregnancy Cuts Child's Birth Weight" Women's Health Weekly (January 31, 2002): 5.

Pope, Harrison G. "Neuropsychological Performance in Long-Term Cannabis Users." JAMA, The Journal of the American Medical Association (January 16, 2002): 296.

Sheldon, Tony. "Netherlands to Run Trials of Marijuana in Patients with Multiple Sclerosis." British Medical Journal (March 2, 2002): 504.

"Study Links Long-Term Marijuana Use with Memory Impairment." Alcoholims & Drug Abuse Weekly (March 11, 2002): 3.

Other

Campaign to Legalize Cannabis International Association. Cannabis Campaigner's Guide, Up-to-Date Chronology of Cannabis Hemp. 2002 [cited January 2003]. .

Deerman, Dixie, RN. The Best Herb You're Not Using That Could Add Years to Your Life! North Carolina: Community of Compassion, 2000.

Goddard, Ian Williams. Proven: Cannabis Is Safe Medicine. 1996 [cited January 2003]. .

Lewin, Louis. Phantastica, Hallucinating Substances, Indian Hemp: Cannabis Indica. 1931 [cited January 2003]. .

Report of the U.S. National Commission on Marihuana and Drug Abuse, 1972. II. Biological Effects of Marihuana, Botanical and Chemical Considerations. 1972 [cited January 2003]. .

Report of the U.S. National Commission on Marihuana and Drug Abuse, 1972. History of Marihuana Use: Medical and Intoxicant. 1972 [cited January 2003]. .

Taima in Japan. Drug War Facts: Marijuana. 1999 [cited January 2003]. .

[Article by: Clare Hanrahan; Teresa G. Odle]

Marijuana is a dried mixture of the leaves and flowers of Cannabis sativa, or hemp plant. Slang words for marijuana include "pot," "weed," "grass," and "dope." The term "cannabis" refers to different psychoactive preparations of the plant, including marijuana, hashish, and hashish oil. Hashish is the resin produced by the flowering tops of the plants; hashish oil is a concentrated form of cannabis extracted from the plant or resin using a solvent. Unpollinated female plants are called sinsemilla (sen-suh-mee-ah) and the flowering tops of these plants produce potent "buds" that do not contain seeds.

The major psychoactive ingredient in cannabis is delta-9-tetrahydrocannabinol (THC), but there are more than sixty related chemicals in marijuana, which are called "cannabinoids." Cannabis also contains other unrelated compounds that have similar psychoactive effects. The World Health Organization reported in 1997 that THC content in marijuana ranges from 0.5 to 4 percent, while concentrations in cannabis oil, hashish, and sinsemilla generally range from 7 to 14 percent, but may be as high as 20 percent. THC concentration depends on the variety, sex, and growing conditions of the plant, and it has increased over the years due to hydroponic cultivation techniques and selective breeding.

Marijuana and other cannabis products are usually smoked as a cigarette (a "joint") or in pipes, but may also be ingested orally. In the 1990s, the use of "blunts" to smoke marijuana became more common. A blunt is made by removing the tobacco from a cigar wrapper and filling it with marijuana, or a mixture of marijuana and some other drug like cocaine.

Psychoactive and Physiological Effects

THC is absorbed more quickly into the bloodstream when smoked than when eaten. Effects are felt almost immediately and peak within thirty minutes of smoking. The marijuana "high" results when the THC binds with cannabinoid receptors in the brain. This process slows down regular nerve transmission, interfering with normal function. The cannabinoid receptors are located in the areas of the brain involved in muscle control, sexual functioning, vision and hearing, reasoning, hormone release, and memory.

Short-term effects include a temporary increase in heart rate, blood pressure, and blood flow to parts of the brain. Users generally feel a sense of euphoria, relaxation, hilarity, and heightened sensory perception. Negative psychological reactions may include anxiety, hallucinations, and panic attacks. Many smokers report that they feel unmotivated when they are high. Cannabis intoxication alters perceptions of time and space and impairs reaction time—affecting the performance of psychomotor tasks such as driving, which increases the risk of motor vehicle accidents. Cannabis increases food intake, impairs learning capabilities, and affects short-term memory. Many cannabis effects are subjective and influenced by the social circumstances, but the extent of impairment mainly depends on the potency and dose of the drug, the individual's tolerance to and experience using cannabis, and the difficulty and complexity of the task at hand.

Long-Term Health Consequences

Many of the studies done on the health consequences of marijuana have been inconclusive, although a picture is emerging of some worrisome long-term health effects. Smoking marijuana affects the respiratory system in much the same way as cigarette smoking. Cannabis smoke contains many of the same toxic chemicals and carcinogens as tobacco, as well as cannabinoids, all of which are respiratory irritants. Frequent marijuana smokers often report laryngitis, hoarseness, and coughing, and they are more likely than infrequent or nonusers to get acute and chronic bronchitis.

In a comprehensive analysis of the health effects of cannabis, the World Health Organization reports that cannabis is known to have adverse effects on the immune system, reproductive system, adrenal hormones, growth hormone, and cognitive function, particularly related to attention and memory processes. The long-term consequences of these effects, however, are not fully known, and further research is warranted. Smoking marijuana during pregnancy reduces oxygen flow to the fetus, which may interfere with growth and result in low birth weight, premature birth, and deficits in verbal ability and memory during childhood.

Preliminary research has demonstrated some positive health benefits of marijuana, including control of nausea and vomiting in people suffering from advanced cancer and AIDS (acquired immunodeficiency syndrome), appetite stimulation for those with wasting diseases, treatment of glaucoma by reducing intraoculer pressure, and control of convulsions and muscle spasms. More research in these areas is needed.

Trends in Marijuana Use

Marijuana use by young people in North America peaked at the end of the 1970s, then declined progressively until the early 1990s, when use began to rise again. In the United States, it appears that the rate of increase may have stabilized at the end of the 1990s, although this stabilization was not apparent in Canada. The Monitoring the Future Survey found that lifetime use of marijuana among U.S. high school seniors peaked in 1979 at 60.4 percent, declined to a low of 32.6 percent in 1992, then rose to 49.6 percent in 1997, where it appears to have leveled off. A 1998 Canadian study on marijuana use did not report use among twelfth graders, but did find that approximately 42 percent of tenth graders had used marijuana in the previous year, up from 25 percent in 1991. In comparison, in 1998 only 31.1 percent of tenth graders in U.S. high schools reported use.

Marijuana use across the entire U.S. population was examined in a household survey in 1992 by the National Institute on Drug Abuse, which reported that 33 percent of Americans age 12 years and over had tried marijuana, 9 percent had used it during the previous year, and approximately 4 percent were current users, though the rate of use varied with age. These figures changed little in the 1998 survey. The proportion of Americans who reported having used marijuana at some point in their life was 11 percent among those 12 to 17 years old, 59 percent among those 26 to 34 years old, and 25 percent among people 35 years old and older.

1n 1994, the Canada Alcohol and Other Drug Survey found that 28 percent of Canadians had used cannabis at least once, 7.4 percent used it in the past year, and 3.2 percent were current users. During the early to mid-1990s, the proportion of people in other countries who reported having tried marijuana was 34 percent in Australia, 43 percent in New Zealand, 37 percent in Denmark, 17 percent in Switzerland and 14 percent in the United Kingdom. In general, marijuana use is lower among European, African, Asian, and South American youth than among young people in North America.

Different subgroups in the North American population report different rates of use. In general, males and white youth report higher rates of marijuana use than females, black youth, or young people from other racial or ethnic backgrounds. Young people who have dropped out of school are more likely to use cannabis than those who are in school, and 84.5 percent of students who attended alternative high schools in 1998 said they had tried cannabis.

Marijuana and Substance Abuse

Since the 1970s, research has consistently demonstrated that adolescents progress through a uniform sequence of drug use involvement that begins with alcohol, cigarettes, and marijuana and proceeds to the use of "hard" drugs like hallucinogens, benzodiazepenes, amphetamines, sedatives, cocaine, and heroin. For this reason, marijuana, alcohol, and tobacco have been called "gateway" drugs. Some studies have shown that use of marijuana is almost a necessary condition for cocaine use by youth. The more frequently and intensively that gateway drugs are used, the greater the likelihood of dependence on the drug and progression to a later stage in the sequence of substance use involvement. However, most young people who use marijuana do not progress to dependence, or use harder drugs. The majority of marijuana users do not use other illicit drugs, although they are more likely to smoke cigarettes and drink alcohol than nonusers. Heavy use of marijuana does, however, place users in contact with more diverse networks of drug users and sellers, thereby increasing their exposure to other drugs and to the influence of those who use them. Participation in street culture is related to marijuana use. Those young people who do progress to abuse other illicit drugs and who experience the most harmful consequences are more likely to be socially and economically disadvantaged.

Prevention

Most cannabis-use prevention programs are school based, and they tend to focus on illicit drugs in general, not just marijuana. The existence of a stable pattern of drug use suggests that prevention efforts should be directed not only at preventing the initiation of use, but also at curbing the transitions from experimental to regular use of any of the gateway drugs and the transition to other drugs. In reviewing what works in drug-use prevention, D. R. Gerstein and L. W. Green found that no prevention programs were reliably effective in all cases with all groups. However, a number of principles for effective prevention have been identified. The U.S. National Institute on Drug Abuse suggests that programs should be comprehensive and long-term, with reinforcement over several years; should target all forms of drug abuse; focus on the family, with a parent or caregiver component; include interactive methods, and be age-specific, developmentally appropriate, and culturally sensitive. School programs are best offered in the sixth through tenth grade, and should include components to develop interpersonal social skills, resistance skills, and self-efficacy, and to improve knowledge of health effects. The higher the level of risk in the specific population, the more intensive and targeted the program should be.

(SEE ALSO: Addiction and Habituation; Behavior, Health-Related; Health Promotion and Education; School Health; Social Determinants; Substance Abuse, Definition of)

Bibliography

Adlaf, E. M.; Ivis, F. J.; Smart, R. G.; and Walsh, G. W. (1995). The Ontario Student Drug Use Survey: 1977–1995. Toronto: Addiction Research Foundation of Ontario.

Ellickson, P. L.; Hays, R. D.; and Bell, R. M. (1992). "Stepping Through the Drug Use Sequence: Longitudinal Scalogram Analysis of Initiation and Regular Use." Journal of Abnormal Psychology 101:441–451.

Gerstein, D. R., and Green, L. W., eds. (1993). Preventing Drug Abuse: What Do We Know? Washington, DC: National Academy Press.

Grunbaum, J.; Kann, L.; Kinchen, S.; Ross, J. G.; Gowda, V. R.; Collins, J. L.; and Kolbe, L. J. (1998) "Youth Risk Behavior Surveillance—National Alternative High School Youth Risk Behavior Survey, United States, 1998." Morbidity and Mortality Weekly Report 48 (SS07):1–44. Available at http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/ss4807al.htm.

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— MARJORIE A. MACDONALD

For more information on marijuana, visit Britannica.com.

A drug-obtained from the hemp plant (Cannabis sativo). Its active ingredient is tetrahydrocannabinol. The psychological effects of marijuana include sedation, euphoria, and relaxation. It is often used as a means of relaxation and escape from tension. It is generally ergolytic, disturbing the sense of balance and blunting assertiveness. Persistent use of marijuana is incompatible with serious sport participation because it tends to demotivate athletes, taking away their will to win. Marijuana is a cannabinoid a group of substances that is on World Anti-Doping Agency's 2005 Prohibited List.

Marijuana, also spelled "marihuana," whose scientific name is cannabis sativa, is a drug obtained from the stems and leaves of the Indian hemp plant. Marijuana is one of the most commonly used drugs in the world: a 1999 survey on drug abuse showed that 75 percent of illicit drug dealers smoked it. It has several intrinsic virtues: it is an analgesic, an anesthetic, an antibiotic, an anti-depressant, and a sedative, depending on its dosage.

Marijuana was introduced into India from China and from there it spread to North Africa and Europe as early as A.D. 500. The Spanish introduced it to the New World in 1545. The English settlers at Jamestown (1611) used hemp produced from the marijuana plant's fibers to make clothes. The hemp industry started in Kentucky in 1775 (in 1860, 40,000 tons were produced). The Harrison Narcotics Act became law in 1914 and aimed at controlling the sale of narcotics. Utah became the first state to pass an anti-marijuana law in 1915, and by 1931 twenty-nine states had criminalized the non-medical use of marijuana. Congress then passed the 1937 Marijuana Tax Act which prohibited its non-medical use while requiring the people producing, distributing, and using it for medical reasons to register and to pay a tax. In 1942, marijuana was removed from the American Pharmacopoeia because of its addictive qualities, and side effects such as anxiety, sleeplessness, paranoia, and altered time perception.

Evaluations of marijuana and its effects vary radically. In the 1950s the beatniks praised it (as would the hippies of the 1960s) as a gesture of protest against materialistic society and as a possible means of attaining enlightenment, though this assumption was later declared mistaken by such a counter-cultural figure as Allen Ginsberg. The 1970 Controlled Substances Act classified it as extremely dangerous and harmful. Until the 1970s marijuana came mostly from Mexico. By 1975 Colombian marijuana had inundated the American market. Because of drastic measures adopted under the Reagan and Bush administrations, such as the 1986 Anti-Drug Abuse Act, marijuana consumption and imports dropped sharply. Some Americans, young and old, however, continued to cultivate it at home, mainly in California and Hawaii. In 1992, the National Institute of Drug Abuse estimated that 67 million Americans—about one out of three—had smoked marijuana at least once in their lives. In 1996 California adopted Proposition 215, which allowed seriously ill people to obtain and consume marijuana for medical purposes. Connecticut, Louisiana, New Hampshire, Ohio, Vermont, and Wisconsin adopted such laws in 1998. Hawaii became the first state to decriminalize marijuana in June 2000. On 14 May 2001 the Supreme Court ruled eight to zero against authorizing the medicinal use marijuana under federal law.

Bibliography

Bonnie, Richard J., Charles H. Whitebread, and Dana L. Farnsworth. The Marijuana Conviction: A History of Marijuana Prohibition in the United States. New York: The Lindesmith Center. 1999.

Mathre, Mary Lynn. Cannabis in Medical Practice: A Legal, Historical, and Pharmacological Overview of the Therapeutic Use of Marijuana. Jefferson, N.C.: McFarland and Company, 1997.

Sloman, Larry R. Reefer Madness: The History of Marijuana inAmerica. Griffin Trade Paperback, 1998.

Dansk (Danish)
n. - marihuana, hash, pot

Nederlands (Dutch)
marihuana

Français (French)
n. - marijuana

Deutsch (German)
n. - Marihuana

Ελληνική (Greek)
n. - μαριχουάνα

Italiano (Italian)
marijuana

Português (Portuguese)
n. - maconha (f) (Bot.)

Русский (Russian)
марихуана

Español (Spanish)
n. - marijuana, marihuana

Svenska (Swedish)
n. - marijuana

中文（简体）(Chinese (Simplified))
大麻

中文（繁體）(Chinese (Traditional))
n. - 大麻

한국어 (Korean)
n. - 마리화나

日本語 (Japanese)
n. - 麻, 乾燥した麻の葉と花

العربيه (Arabic)
‏(الاسم) المارغوانا, نبات الحشيشه (الكيف)‏

עברית (Hebrew)
n. - ‮חשיש, מריחואנה‬

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