In common usage, marijuana refers to the dried flowers of the cannabis plant. These flowers are typically smoked to produce a psychoactive high. In addition, the flowers and other parts of the plant can be processed into hashish, oils, extracts, and other refined products that can be smoked, eaten, and vaporized. The effects of the high can be subjective and often vary depending on whether the user consumed a Cannabis sativa strain, a Cannabis indica strain, or a hybrid strain.
Beyond its popularity as a recreational drug, marijuana also has medicinal applications and its increasing use as a holistic therapy has helped bring about the development of novel delivery methods. These include tinctures, balms, transdermal patches, and microdosing preparations. Biopharmaceutical companies working with cannabis are also in the process of creating a new generation of controlled delivery methods including regular and time-release capsules with standardized dosages.
Recreational marijuana use is common in the United States. According to results from the annual National Survey on Drug Use and Health, 17.5 percent of Americans age twelve and older reported using marijuana in 2019. Marijuana use is most common among people between eighteen and twenty-five years old. Though federal law has prohibited the sale and possession of marijuana since 1937, thirty-six states, the District of Columbia, Guam, Puerto Rico, and the US Virgin Islands have legalized cannabis use in some capacity, typically for medical purposes. As of January 2021, recreational adult use of marijuana has been approved in fifteen states and the District of Columbia.
According to a Gallup poll conducted in November 2020, 68 percent of Americans support legalizing marijuana. Public support has steadily increased since Gallup began surveying Americans on cannabis legalization in 1969, when only 12 percent of respondents supported it. Gallup polling has revealed several motivations for supporting legalization, including an appreciation of the plant's medical benefits, a desire to free up law enforcement resources, the promise of state and local tax revenue, belief that cannabis use should be a personal choice, and anticipation that government regulation will make its use safer. Opponents of cannabis legalization have expressed concerns about its impact on public safety, noting that legalization may result in more impaired driving and contribute to users moving on to harder drugs.
The psychoactive substance that produces the "high" associated with marijuana is known as tetrahydrocannabinol (THC). THC is one of many chemical compounds present in marijuana known as cannabinoids and is the only cannabinoid proven to produce intoxicating effects. The effects of cannabis use can differ, depending on factors such as the strain of marijuana consumed by the user, the level of THC content, and the consumption method.
Marijuana use commonly causes altered sensory perception. It can also induce temporal distortions, making time seem to pass more slowly. Mood changes can occur; these effects tend to be highly subjective and dependent on the user's mental and emotional state. Many users report that the high causes difficulty with sequential reasoning and problem-solving but stimulates creativity and free-associative thought. At very high doses, marijuana can also induce delusions and hallucinations.
Cannabis users report that sativa strains induce a more energetic high suitable for socializing and creative thinking, while indica strains produce a heavier, more sedative effect. Hybrid strains of the plant, which are typically cultivated to contain a certain percentage of sativa parentage and a certain percentage of indica parentage, can produce different combinations of these effects. Smoked or vaporized cannabis products enter the bloodstream quickly and produce a near-instantaneous high, while edible preparations and tinctures are absorbed at a slower rate and usually take at least thirty to sixty minutes to produce any noticeable effects.
The subspecies Cannabis ruderalis naturally has extremely low concentrations of THC and is not typically consumed recreationally because it does not produce psychoactive effects. However, the plant has been used in traditional medicines in Central Asia. Further, cannabis growers have experimented with blending the subspecies with sativa and indica trains because of its sturdiness and its ability to flower regardless of the light cycle.
Marijuana use can have both short-term and long-term physical and mental effects. Short-term physical effects include decreased blood pressure, increased heart rate, and dry mouth. If the drug is smoked, it also constricts blood vessels. The increase in heart rate associated with marijuana is considered risky for people with heart disease and other cardiovascular conditions. The short-term mental effects of marijuana use include confusion, sedation, impaired memory, inattentiveness, and diminished concentration. Users may also experience psychological side effects including anxiety, paranoia, panic, and delusional or psychotic behavior. More extreme psychological reactions are typically associated with higher dosages.
With regular long-term use, the physical effects of marijuana can include bronchitis, lung infections, and a chronic cough. Mental faculties that can be negatively affected include concentration, memory, and decision-making abilities. Some studies suggest that long-term use could lower a person's intelligence quotient (IQ) score. Such claims have faced scrutiny from researchers who challenge the methodologies and sample sizes used in these studies.
Research also suggests links between marijuana use and serious mental illnesses such as psychosis and schizophrenia. These links are strongest in people who began using the drug at a young age, use the drug heavily and frequently, and have a family history of psychosis and schizophrenia. In general, negative marijuana-related long-term physical and mental health outcomes are more likely to occur in heavy, regular users and users who begin taking the drug at a young age, particularly during adolescence and early adulthood when the brain is still developing.
A commonly held belief suggests that marijuana does not cause physical addiction. However, most mental health professionals recognize the potential for users to develop a psychological dependence on the drug. The distinction between physical addiction and psychological dependence is that addiction causes physical withdrawal symptoms when the drug is discontinued, while dependence causes withdrawal symptoms that are purely emotional and psychological in nature. However, experts stress that characterizing marijuana in this way is inaccurate and misleading because physical addiction can occur in rare cases, primarily in very heavy chronic users. Mental health professionals believe a person has developed marijuana use disorder when cannabis use interferes with a person's life and the person has trouble refraining from use.
Some public health officials, addiction experts, and researchers believe that marijuana may act as a gateway drug, meaning that using it creates an increased chance that a person will go on to take other drugs. While the National Institute on Drug Abuse (NIDA) acknowledges marijuana's potential as a gateway drug, it also concedes that the majority of marijuana users do not go on to experiment with or use other, more dangerous substances.
Medical experts have recognized marijuana's potential therapeutic value in treating a wide range of symptoms and conditions including chronic pain, seizures, inflammation, nausea, and insomnia. Research suggests that cannabis can also ease symptoms like the muscle spasms and stiffness of progressive neurological disorders such as multiple sclerosis (MS). Additionally, marijuana has been shown to help treat nausea and vomiting in some cancer patients undergoing chemotherapy and to counteract loss of appetite among people with HIV/AIDS. When combined with other therapies, it may also help individuals suffering from post-traumatic stress disorder (PTSD).
Marijuana also has been cited as a possible solution for the abuse of harder drugs, particularly opioids. The products of cannabis plants have noted analgesic properties and are being investigated as possible alternatives to the powerful narcotic painkillers that have contributed to high rates of opioid addiction in the United States and other countries. Several studies have shown that states with legal access to medical marijuana have fewer opioid-related deaths. No death has ever been attributed to marijuana overdose.
Proven and potential medical applications have helped marijuana regain legal status after a decades-long prohibition on all uses of the drug. At the state level, marijuana was first criminalized in 1911 in Massachusetts; federal prohibition followed in 1937 with the passage of the Marihuana Tax Act. California became the first state to relegalize marijuana in 1996, approving it only for medical purposes. As of 2021, medical marijuana has been legalized in thirty-six states and the District of Columbia, Guam, Puerto Rico, and the US Virgin Islands.
The Agriculture Improvement Act of 2018, more commonly referred to as the Farm Bill, changed the legal status of hemp, a type of cannabis that contains less than 0.3 percent of THC and has traditionally been used to make clothing, rope, and other durable products. Through this change, Congress made allowances for the study of the potential effects of using hemp and the sale of some hemp-derived products, particularly those containing cannabidiol (CBD). CBD is not psychoactive and can be found in all forms of cannabis. Interest in CBD products increased after the law's passage, though a consensus has not been reached on the full benefits of CBD. Several studies, however, indicate that it can be effective at treating certain epilepsy syndromes. As of January 2021, eleven states that otherwise forbid cannabis consumption provide allowances for the use of CBD products under certain circumstances.
As medical marijuana gained widespread acceptance, activists turned to advocating the legalization of the drug for recreational purposes. As of January 2021, Alaska, Arizona, California, Colorado, Illinois, Maine, Massachusetts, Michigan, Montana, Nevada, New Jersey, Oregon, Vermont, and Washington as well as the District of Columbia have approved recreational marijuana use by adults.
Except when considering the potential medical benefits of hemp, federal law considers cannabis an illegal substance and makes no distinction between medical and recreational use. In 2020 the US House of Representatives passed the Marijuana Opportunity Reinvestment and Expungement Act (MORE Act), which would have decriminalized marijuana at the federal level and removed it from the list of controlled substances. However, the bill stalled after the Senate chose not to vote on it. Lawmakers returned to the issue during the first week of the next congressional session in January 2021 when Representative Greg Steube (R-FL) introduced a bill that would not decriminalize cannabis but would reclassify it as a less serious substance. Many observers, particularly cannabis investors, expressed optimism that the federal status of marijuana would change with Democrats gaining control over the executive branch and both bodies of Congress in 2021 as well as increased support for reform among Republicans.
The legalization of recreational marijuana has had positive and negative impacts. On the positive side, states with legal recreational marijuana have enjoyed a major increase in tax revenues. Colorado, which was the first state to legalize the drug for adult recreational use, reported over $1 billion in revenue from marijuana sales between January 2014 and June 2019, including $266.5 million in 2018 alone. A 2017 study also showed that if marijuana were legalized in the United States at the federal level, it would generate $132 billion in tax revenue and create over one million jobs over the ten-year period spanning 2017–2026. In addition, legalization would disrupt the criminal networks that control the production and distribution of the drug in areas where it is prohibited, denying them a major source of revenue. A reduction in the illegal distribution of marijuana would also theoretically make it more difficult for minors to access the drug.
Though public support for cannabis legislation continues to grow in the United States, citizens remain concerned about the risks of impaired driving. The American Automobile Association's Traffic Safety Culture Index reported in 2019 that 70 percent of Americans considered driving after using cannabis to be highly dangerous and over 80 percent supported laws criminalizing marijuana-impaired driving. In a survey conducted by the Colorado Department of Transportation (CDOT) in 2018, 22.3 percent of marijuana users reported having driven within three hours of using the drug during the previous year. According to CDOT reporting, 19 percent of 2017 traffic fatalities in the state among drivers tested for drugs had high levels of THC in present in their blood.
Testing positive for marijuana use after a collision, however, does not prove the person was impaired while driving, as the drug can stay in a person's system for several weeks after use. The lack of a reliable, universally accepted roadside screening test for marijuana impairment poses another complication for addressing impaired driving. While such tests are actively being developed, law enforcement officials must rely on controversial screening processes, including swab tests that are said to yield inaccurate and inconsistent results and field sobriety tests that involve the application of police officers' own judgment. Many police agencies have also indicated that officers frequently lack the knowledge and training to spot the signs of marijuana impairment, which can allow drug-impaired drivers to escape undetected even if they are stopped by police.
Changing marijuana laws have created some legal issues without clear answers. For example, many activists have called for marijuana amnesty, which would erase previous convictions from the criminal records of people found guilty of cannabis possession in states that have legalized it. Such amnesty would likely necessitate the release of people incarcerated for marijuana offenses. In addition, amnesty raises the possibility of paying reparations to individuals who suffered under the law. However, with marijuana remaining prohibited at the federal level, there is no obvious path forward for such a policy at the national level, even though public support for amnesty is strong. As marijuana prohibition has disproportionately resulted in the arrest and incarceration of people of color, many activists have argued that any legal cannabis industry must provide opportunities through which the communities most affected can benefit from its revenue.
The transportation of recreational marijuana from a state where it is legal to a state where it is not legal causes further complications for law enforcement. Existing federal statutes make interstate transport of marijuana or marijuana products illegal. However, the rise of novel consumption methods such as marijuana-infused beverages, chocolates, and candies has presented law enforcement officials with significant detection and enforcement challenges. Further, in states where such consumption methods are legal, authorities have reported cases of minors mistaking the drug for something safe to eat.
"Marijuana has been used throughout the world for thousands of years, and its medicinal benefits are incontrovertible."
In the following viewpoint, the Drug Policy Alliance argues that marijuana is safe and effective as a medicine for the treatment of many illnesses. The alliance reports that because of this and the change in public opinion, about half the states now allow the use of medical marijuana. The author claims that the federal government should not interfere with the states and should do more to support research about medical marijuana. The Drug Policy Alliance is a national advocacy leader of drug law reform that is grounded in science, compassion, health, and human rights.
"Legalizing the marijuana plant ... and allowing open access to it is not necessary and may even create a public health danger for seriously ill patients."
In the following viewpoint, the Drug Free America Foundation, Inc. (DFAF) argues that there is no justification for legalizing use of the marijuana plant as medicine. DFAF claims that there is already a synthetic marijuana-component pharmaceutical product on the market prescribed for medical purposes, and more research is under way for potential effective and safe use of natural or synthetic components of the marijuana plant. DFAF is a drug policy and prevention organization committed to creating an environment where citizens live free of illicit drugs.
“Despite its benefits, decriminalization falls short in many ways—largely because it still lies within the framework of prohibition.”
In the following viewpoint, the Drug Policy Alliance argues that marijuana prohibition has failed, but marijuana decriminalization policies do not go far enough to remedy the problems with prohibition. The alliance contends that decriminalization does not prevent arrests and criminal records and does nothing to address the harms of the underground—and often violent—marijuana trade. The alliance contends that marijuana ought to be legal, taxed, and regulated in a manner similar to alcohol. The Drug Policy Alliance is a national advocacy leader of drug law reform that is grounded in science, compassion, health, and human rights.
“Indeed, decriminalization doesn’t change the social conditions that sustain both marijuana use and racially biased responses to it.”
Chris S. Duvall is an associate professor of geography at the University of New Mexico. He is the author of Cannabis, a history of marijuana use throughout the world. In the following viewpoint, Duvall breaks down the historical racial and class biases associated with marijuana. He identifies many misconceptions that persist in the debate over drug legalization, including the idea that African slaves introduced marijuana to the United States and the belief that decriminalization is enough to remove the racial stigma surrounding the drug. However, Duvall states, decriminalization will have a number of benefits, including fewer arrests in minority neighborhoods. He urges readers to consider marijuana’s role in society and explains how tax revenues from legally sold marijuana could be applied to services for those in low-income communities.