Botanical name: Cannabis sativa
Other common names: weed, pot, herb, bud, dope, spliff, reefer, grass, ganja, 420, chronic, Mary Jane, gangster, boom, skunk. There are over 200 street names for marijuana.
What is Marijuana?
Marijuana is a green, brown or gray mixture of dried, shredded leaves, stems, seeds and flowers of the hemp plant Cannabis sativa. Marijuana is used as a psychoactive (i.e. mind altering) recreational drug, for certain medical ailments and for religious and spiritual purposes. Sinsemilla, hash/hashish (resinous form) and hash oil (sticky black liquid) are stronger forms of marijuana.
How does Marijuana work?
The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). It is a psychoactive ingredient. The highest concentrations of THC are found in the leaves and flowers. When marijuana smoke is inhaled, THC rapidly passes from the lungs into the bloodstream and is carried to the brain and other organs throughout the body. THC from the marijuana acts on specific receptors in the brain, called cannabinoid receptors, starting off a chain of cellular reactions that finally lead to the euphoria, or "high" that users experience.
Certain areas in the brain, such as the hippocampus, the cerebellum, the basal ganglia and the cerebral cortex, have a higher concentration of cannabinoid receptors. These areas influence memory, concentration, pleasure, coordination, sensory and time perception.1 Therefore these functions are most adversely affected by marijuana use.
Marijuana's strength is correlated to the amount of THC it contains and the effects on the user depend on the strength or potency of the THC. The THC content in marijuana has been increasing since the 1970s. For the year 2007, estimates from confiscated marijuana indicated that it contains almost 10 percent THC on average. There are many other chemicals found in marijuana, many of which may adversely affect health.2 Marijuana contains over 60 different cannabinoid compounds related to THC, including cannabidiol, cannabinol, and β-caryophyllene.
Marijuana is usually smoked as a cigarette (called a joint or a nail) or in a pipe or bong. In recent years, it has appeared in blunts, which are cigars that have been emptied of tobacco and refilled with marijuana, often in combination with another drug, such as crack. The “blunts” retain tobacco leaf used to wrap the cigar and therefore it combines marijuana's active ingredients with nicotine and other harmful chemicals. Some users also mix marijuana into food or use it to brew tea.
Medicinal use of THC
In the United States, the Controlled Substances Act (CSA) of 1990 classifies marijuana as a Schedule I substance, which has no approved medical use and has high potential for abuse. However, some US states have legalized the use of marijuana or medical or recreational use. Prescription medicines containing synthetic cannabinoids (THC) are already available.
Both medications are used to treat chemotherapy patients who have nausea, vomiting and loss of appetite. However, Marinol is also approved to treat HIV patients with cachexia (weight loss, muscle atrophy, fatigue and loss of appetite).
Studies have also been done which show that THC and cannabidiol (CBD) provide therapeutic benefit for Multiple Sclerosis (MS) spasticity symptoms.3 In Canada, Europe, the UK, Spain, Germany, Denmark, the Czech Republic, Sweden, and New Zealand, Sativex, an oral sublingual spray, is available for adjunctive use in MS neuropathic pain and cancer-related pain. Sativex® is composed of plant-derived extracts of THC and cannabidiol, not synthetic cannabinoids. In 2013, Sativex was in Phase II and III clinical trials for US approval for use in MS spasticity and cancer pain, and has the adopted generic name of nabiximols. Dronabinol has also been used in Europe for treatment of MS-related pain.
- Sativex (nabiximols)
Marijuana has also been used for glaucoma to lower intraocular pressure (IOP), but research does not show that marijuana has a better effect than currently approved glaucoma medications. Studies have shown that smoked, oral or IV use may have an effect on lowering IOP, but topically applied marijuana derivatives to the eye did not have an effect. Marijuana is not FDA approved for use in glaucoma, and may lead to other side effects such as increased heart rate and lowered blood pressure. 4 However, in some US states, marijuana is used for glaucoma under medical marijuana programs.
Extent of Marijuana Use
In January 2014, marijuana was noted by the National Institute on Drug Abuse as being the most widely used illicit drug in the U.S. Globally, between 129 and 191 million people aged 15 to 64 used marijuana at least one time in 2008, or 2.9 to 3.4 percent of the world's population. In North America, 29.5 million people used marijuana at least once in 2008.5 According to the 2010 National Survey on Drug Use and Health (NSDUH), marijuana was used by 76.8 percent of current illicit drug users (defined as having used the drug at some time in the 30 days before the survey) and was the only drug used by 60.1 percent of them.
Data indicate that in 2008 marijuana was responsible for about 17 percent (322,000) of all admissions to treatment facilities in the United States. Only opiates have a higher admission rate among abused substances. Marijuana admissions were primarily male (74 percent), white (49 percent), and young (30 percent were in the 12-17 age range). Starting marijuana by age 14 was a common factor among 56 percent of those admitted for treatment.1
According to the 2011 National Survey on Drug Use and Health, 2.6 million Americans aged 12 or older used marijuana for the first time in the 12 months prior to being surveyed (roughly 7,200 new users per day), which is similar to the 2009-2010 rate (2.4 million each), but higher than the estimates in 2002 through 2008. Close to 58 percent of the 2.4 million recent marijuana users were younger than age 18 when they first used. Among all youths aged 12 to 17, an estimated 5.5 percent had used marijuana for the first time within the past year, which was similar to the rate in 2010 (5.2 percent).6
The 2012 Monitoring the Future survey indicates that marijuana use among 8th-, 10th-, and 12th-graders, which had shown a consistent rise over 2010 and 2011, leveled off in 2012. Daily marijuana use increased significantly in all three grades in 2010, 1.2%, 3.3.% and 6.1% in grades 8, 10 and 12, which computes to roughly one out of every 16 high school seniors who smoke marijuana daily.7 These trends increased slightly in the higher grades in 2012, with 1.1%, 3.5%, and 6.5% in grades 8, 10, and 12 using marijuana daily.7
Perceived risk and individual disapproval of marijuana is a leading indicator of marijuana use among teens in the U.S. In all grades in 2012, those who perceived smoking marijuana as harmful and the proportion who disapprove of the drug’s use have slightly declined, suggesting use may increase in upcoming years. In 2012, 37% of 8th graders, 69% of 10th graders, and 82% of 12th graders reported marijuana as being fairly or very easy to get. It thus seems clear that marijuana has remained highly accessible to the older teens.
Effects during Pregnancy and Breastfeeding
Any drug of abuse can affect a mother's health. THC can cross the placenta so there is potential for problems in the fetus. THC can depress the fetal heart rates and change fetal brain wave electrical patterns. Studies have found that babies born to mothers who used marijuana during pregnancy were smaller than those born to mothers who did not use the drug. In general, smaller babies are more likely to develop health problems. Tests given to children at 48 months of age whose mothers used marijuana during pregnancy have shown lower verbal and memory scores compared to children whose mother did not use marijuana.  Babies born to adolescents who used marijuana during pregnancy have also shown adverse effects on the neurological behavior of the newborns in the first 24 to 78 hours after delivery.9
A nursing mother who uses marijuana passes some of the THC to the baby in her breast milk.8 Research indicates that use by a mother during the first month of breast-feeding can impair the infant's motor development. Pregnant and nursing women should avoid marijuana use.
Marijuana side effects
What are the short-term side effects of Marijuana use?
Side effects of marijuana use will be variable from person to person, depending upon strength and amount of marijuana used and if the user is occasionally or chronically exposed to THC. The short-term effects of marijuana use include problems with memory and learning; distorted perception (sights, sounds, time, touch); difficulty in thinking and problem solving; loss of coordination and motor skills; increased heart rate, anxiety, bloodshot eyes, dry mouth. Reaction time may be impaired while driving. Panic attacks, paranoia and psychosis may occur acutely and be more common in psychiatric patients.10. For chronic users, the impact on memory and learning can last for days or weeks after its acute effects wear off.1 Marijuana may be cut on the street with more dangerous substances that may lead to more serious side effects.
THC in marijuana is strongly absorbed by fatty tissues in various organs. Generally, traces of THC can be detected by standard urine testing methods several days after a smoking session. In heavy chronic users, traces can sometimes be detected for weeks after they have stopped using marijuana.
What are the long-term side effects of Marijuana use?
People who smoke marijuana often have the same respiratory problems as cigarette smokers. These individuals may have daily cough and phlegm, symptoms of chronic bronchitis, and more frequent chest colds. They are also at greater risk of getting lung infections like pneumonia. Marijuana contains some of the same, and sometimes even more, of the cancer-causing chemicals found in cigarette smoke. A study from 2009 suggests that regular and long-term use of marijuana may increase the risk for testicular cancer.
When people smoke marijuana for years they can suffer negative consequences. For example, because marijuana affects brain function, the ability to do complex tasks could be compromised, as well as the pursuit of academic, athletic, or other life goals that require you to be 100 percent focused and alert. Long-term abuse of marijuana may lead to addiction.
Marijuana also may affect mental health. Studies show that early use may increase the risk of developing psychosis (a severe mental disorder in which there is a loss of contact with reality) including false ideas about what is happening (delusions) and seeing or hearing things that aren’t there (hallucinations), particularly if you carry a genetic vulnerability to the disease. Also, rates of marijuana use are often higher in people with symptoms of depression or anxiety.2
Effects of Marijuana On Other Organs
Effects on the Heart
Shortly after smoking marijuana the heart rate increases drastically and may remain elevated for up to 3 hours. This effect may be enhanced if other drugs are taken with marijuana. One study has suggested that the risk of heart attack may increase by up to 4.8-fold in the first hour after smoking marijuana.11 The effect may be due to the increased heart rate, as well as altered heart rhythms. The risk of heart attack may be greater in those with specific risk factors such as patients with high blood pressure, heart arrhythmia, or other cariac disease.
Effects on the Lungs
After smoking marijuana, the bronchial passage relaxes and becomes enlarged, and the blood vessels in the eyes expand making the eyes look red. Studies have shown that marijuana smoke contains 50-70 percent more carcinogenic hydrocarbons than tobacco smoke, and is an irritant to the lungs. Marijuana users tend to inhale more deeply and hold their breath longer than tobacco smokers do, which further increase the lungs' exposure to carcinogenic smoke. Marijuana smokers can have many of the same respiratory problems as tobacco smokers, such as daily cough and phlegm production, more frequent acute chest illness, and a heightened risk of lung infections.1 A case-controlled study from 2006 found no links between marijuana use and lung cancer, but no evidence-based consensus has been definitively made on the absolute risk of lung cancer with marijuana use.12
Effects of Heavy Marijuana Use on Social Behavior
Heavy marijuana abuse may show low achievement in important life measures including mental and physical health, and career. Marijuana affects memory, judgment and perception. Learning and attention skills are impaired among people who use it heavily. Longitudinal research on marijuana use among young people below college age indicates those who use marijuana have lower achievement than the non-users, more acceptance of deviant behavior, more delinquent behavior and aggression, greater rebelliousness, poorer relationships with parents, and more associations with delinquent and drug-using friends.
Smoking marijuana can make driving dangerous. The cerebellum is the section of our brain that controls balance and coordination. When THC affects the cerebellum’s function it can cause disaster on the road. Research shows that drivers have slower reaction times, impaired judgment, and problems responding to signals and sounds if driving while under the influence of THC.2
A drug is addicting if it causes compulsive, uncontrollable drug craving, seeking, and use, even in the face of negative health and social consequences. Research suggests that roughly 9 percent of users become addicted to marijuana, with higher rates if the user starts at a young age (17 percent) and in those who use marijuana daily (25-50 percent). While not everyone who uses marijuana becomes addicted, when a user begins to seek out and take the drug compulsively, that person is said to be dependent or addicted to the drug.
Long-term users who try to quit could experience withdrawal symptoms such as sleeplessness, irritability, anxiety, decreased appetite and drug craving. Withdrawal symptoms usually begin about a day after the person stops using marijuana, peaks in 2 to 3 days and may take about 1 to 2 weeks to subside.
Some heavy users develop a tolerance to marijuana; meaning that the user needs larger doses to get the same desired results that he or she used to get from smaller amounts.1
As of July 2014, 23 states and the District of Columbia legally allow marijuana for personal medical use. Rules surrounding the use of medical marijuana vary by state. The first state in the union to legalize the medical use of marijuana was California in 1996. Other states that allow medical marijuana include: Alaska, Arizona, California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Washington, and the District of Columbia. It is important to recognize that these state marijuana laws do not change the fact that using marijuana continues to be an offense under Federal law.
Medical marijuana in the U.S. is controlled at the state level. Per federal law, cannabis is illegal as noted in the Controlled Substances Act, but the federal government has stated they will not actively prosecute patients and caregivers complying with state medical marijuana laws. However, use of medical marijuana outside of the state laws for illegal use or trafficking will not be tolerated by state or federal government.
There are eight medical conditions for which patients can use cannabis:
- Muscle spasms
- Severe pain
- Severe nausea
- Cachexia or dramatic weight loss and muscle atrophy (wasting syndrome)
According to various state laws, medical marijuana can be used for treatment of other debilitating medical conditions, such as decompensated cirrhosis, amyotrophic lateral sclerosis, Alzheimer's disease, and post-traumatic stress disorder. Not all states that approve of medical marijuana have enacted laws to allow its use for all of these conditions. Another difference between states - the amount of marijuana for medical use that can be possessed by the individual patient or primary caregiver varies, but may include dried marijuana and live plants.
In healthcare, the use of marijuana for medical reasons is controversial. In November 2013, the American Medical Association (AMA) voted to retain an official position that "cannabis is a dangerous drug and as such is a public health concern," but also acknowledged the changing attitudes toward marijuana among the American public. The AMA calls for laws “to emphasize public health based strategies to address and reduce cannabis use" and state that criminal laws for the illegal possession of marijuana for personal, recreational use focus on "public health based strategies, rather than incarceration."
The American Medical Association (AMA) encourages continued research of marijuana and related cannabinoids in patients who have serious conditions. AMA also states that marijuana’s status as a federal schedule I controlled substance should be reviewed "with the goal of facilitating the conduct of clinical research and development of cannabinoid-based medicines, and alternate delivery methods. This should not be viewed as an endorsement of state-based medical cannabis programs, the legalization of marijuana, or that scientific evidence on the therapeutic use of cannabis meets the current standards for a prescription drug product." The AMA continues to stand strong against the legalization of marijuana for recreational use. The AMA also rejected a proposal to advocate for the "sale of cannabis to be regulated on a state-based level.”13
Several states are now considering or have passed bills to allow legalization of medical marijuana oil (CBD oil or Realm Oil) for intractable seizures in children with Dravet Syndrome. These children can suffer 40 more seizures per day; the seizures are often prolonged in length. The oil is made a from a special strain of marijuana called “Charlotte's Web” that has extremely low levels of tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana that leads to the “high”. However, the strain has elevated levels of cannabidiol, or CBD, a non-psychoactive component that has been shown to have a number of therapeutic benefits, including those that limit seizure activity. The oil is taken in an oral liquid form, not smoked like traditional marijuana.14 News media has showcased several families from states that do not allow the CBD oil. These families have moved to Colorado from their home states to access the oil legally for their children who suffer from the debilitating seizures. Legislation is currently under review in several states to allow the oil for children with this debilitating seizure condition. As of June 7, 2015, in addition to the states that allow medical marijuana, 15 states had okayed the use of CBD oil: these states include Utah, Texas, Alabama, Kentucky, Missouri, Wisconsin, Mississippi, Tennessee, Georgia, South Carolina, Iowa, Florida, North Carolina, Virginia and Illinois.
Political leaders, US government officials, health care providers and medical organizations take differing views of the benefits and risks of medical marijuana. Proponents state that marijuana has valid medical uses and further research should be pursued, while opponents list concerns about health risks, and the "gateway" effect of marijuana that can lead to more dangerous drug abuse, among other issues. Nonetheless, legalization of medical marijuana continues to be pursued at the state level, with pending legislation in multiple states.15
Recreational Use of Marijuana
In 2012, voters in Colorado and Washington state passed initiatives legalizing marijuana for adults 21 and older under state law. The states of Oregon and Alaska, as well as Washington, D.C also voted to approve recreational use of marijuana in November 2014. It is important to note that the federal government still considers marijuana a dangerous drug and that the illegal distribution and sale of marijuana is a serious crime. Under the Controlled Substances Act (CSA), marijuana is still considered a Schedule 1 drug. Cultivation and distribution of marijuana are felonies; possession for personal use is a misdemeanor; possession of “paraphernalia” is also illegal. Cultivating 100 plants or more carries a mandatory minimum sentence of five years according to federal statutes.16
That being said, it is unlikely that the federal government is interested in pursuing individuals complying with state-mandated regulations surrounding legalized marijuana for recreational use, although the CSA law still gives them authority to do so.
The Department of Justice (DOJ) has attempted to clarify this issue.17 On August 29, 2013, the DOJ issued guidance to Federal prosecutors concerning marijuana enforcement under the CSA. The DOJ is focused on priorities, such as:
- Preventing the distribution to minors
- Preventing revenues from sale of marijuana towards criminal activity
- Preventing diversion of marijuana from states where it is legal to states where it is not legal
- Preventing state-legalized marijuana from being a cover for other illegal drugs or activity
- Prevent violence and guns in the cultivation and distribution of marijuana
- Prevent drugged driving and other public health issues
- Prevent the use of public land for marijuana cultivation
- Preventing marijuana possession or use on federal property
Additional states may undertake or pursue citizen petitions in the future to legalize the recreational use of marijuana. According to the Brookings Institute, Presidential years bring out an electorate more favorable to marijuana legalization than the off-year electorate.16 Other states pursuing legalization may include California, Arizona, Nevada, Massachusetts, Montana, Rhode Island, and Vermont.18 Maine and Michigan citizen voters have also passed legalization of marijuana for recreational use, but state law will likely override these voter referendums; only medical marijuana is currently legal according to state law in these states.
A majority of Americans support legalization of marijuana -- 52 percent pro versus 45 percent con -- according to findings from a Pew Research Center survey in March 2013. Support for marijuana legalization has increased dramatically since 2010, by 11 percentage points. 16
Colorado passed Colorado Amendment 64 on November 6, 2012, allowing the sale and possession of recreational marijuana. Adults 21 years and older can grow up to three immature and three flowering, mature cannabis plants privately and in a locked space. Adults can legally possess all the cannabis from the plants in the place it was grown, but when traveling away from this place may only possess one ounce in total. In addition, an adult may give up to one ounce to another adult at least 21 years of age; it cannot be sold.
On January 1, 2014, retail marijuana shops opened for business in Colorado, and sales of marijuana are now taxed at the state level. Retail taxes on recreational marijuana can be lofty; in the Denver metro area they can exceed 20 percent. In January 2014 alone, Colorado pulled in over $2 million in taxes from recreational marijuana sales.19
Specific city and county laws have been enacted to regulate how citizens and tourists may possess and consume marijuana. Penalties exist for driving while under the influence of marijuana. Someone driving under the influence of marijuana is considered impaired when five nanograms per milliliter (ng/mL) of blood or more of active THC is detected, according to the Colorado Department of Transportation. Tourists to the city may purchase a quarter ounce at retail shops, instead of the one ounce for state residents. The newly formed Colorado Marijuana Enforcement Division of the Department of Revenue regulates recreational marijuana in the state.
On November 6, 2013 the state of Washington passed Washington Initiative 502, also legalizing marijuana possession and sale for recreational use for adults 21 years and older. The initiative was approved by popular vote, passing by roughly 56 to 44 percent. Like Colorado, Washington taxes marijuana cultivation and sales. Washington’s retail tax rate on marijuana is somewhat higher than Colorado’s, at roughly 30 to 40 percent.19 However, additional excise taxes are implemented in the supply chain. It has been reported that tax dollars will be directed to schools, youth drug abuse programs, and campaigns to hinder driving while under the influence of marijuana.
Washington residents cannot grow recreational marijuana for personal use, although they can cultivate medical marijuana if it is approved by a physician for their use. Residents may possess up to one ounce of marijuana, previously a misdemeanor charge. The same rules for driving under the influence in Colorado apply to Washington residents.
The state of Washington will be issuing the first retail store licenses in March 2014; they are expected to open in June 2014. The commercial market in Washington State is regulated by the Washington State Liquor Control Board.
- Bath Salts
- PCP (Phencyclidine)
- Psilocybin (mushrooms)
- Speed (methamphetamine)
- Synthetic Marijuana (Spice or K2)
Recommended for you
- National Institute on Drug Abuse (NIDA). NIH. NIDA Info Facts. 11/10. Accessed 9/22/2011
- National Institute on Drug Abuse (NIDA) for Teens. NIH. Marijuana. Accessed 9/22/2011
- Lakhan SE, Rowland M. Whole plant cannabis extracts in the treatment of spasticity in multiple sclerosis: a systematic review. BMC Neurology 2009:9;59
- National Eye Institute (NEI). NEI Statement. Glaucoma and Marijuana Use. National Institute of Health. May 13, 2009. Accessed 9/22/2011
- UNODC. World Drug Report 2010. United Nations Publication, 2.4 Cannabis. p. 194. Retrieved September 22. 2011
- U.S. Department of Health and Human Services. Substance Abuse and Mental Health Services Administration. Office of Applied Studies. Results from the 2011 National Survey on Drug Use and Health: Summary of National Findings. Accessed June 16, 2013
- Monitoring the Future. National Results on Adolescent Drug Use. Overview of Key Findings 2012. Accessed June 16, 2013
- Coustan DR, Mochizuki TK. Handbook of Prescribing Medications During Pregnancy. Third Edition. Lippincott-Raven Publishers 1998.
- de Moraes Barros MC, Guinsburg R, de Araújo Peres C, et al. Exposure to marijuana during pregnancy alters neurobehavior in the early neonatal period. J Pediatr. 2006;149:781-7.
- Jacob L Heller, MD, MHA. Marijuana Intoxication. Medline Plus. NLM/NIH. 1/5/2011. Accessed 9/22/2011
- Mittleman MA, Lewis RA, Maclure M, et al. Triggering myocardial infarction by marijuana. Circulation 2001;103(23):2805-9. Hashibe M, Morgenstern H, Cui Y, et al. Marijuana use and the risk of lung and upper aerodigestive tract cancers: Results of a population-based case-control study. Cancer Epidemiol Biomarkers Prev 2006;15(10):1829-34.
- American Medical Association. Report 3 of the Council on Science and Public Health (I-09)
Use of Cannabis for Medicinal Purposes (Resolutions 910, I-08; 921, I-08; and 229, A-09). 2009. Accessed March 17,2014.
- Parents Move to Colorado for Miracle Pot for Children. USA Today. February 18, 2014. Accessed March 16, 2014
- ProCon.org. Medical Marijuana. Accessed March 16, 2014
- The Brookings Institute. Brookings. Q&A: Legal Marijuana in Colorado and Washington. May 21, 2013. Accessed March 17, 2014
- U.S. Department of Justice. Office of the Deputy Attorney General. Memorandum: Guidance Regarding Marijuana Enforcement. August 29, 2013. Accessed March 17, 2014
- The Huffington Post. These States are Most Likely to Legalize Pot Next. August 30, 2013. Accessed March 17, 2014
- Forbes. It’s No Toke: Colorado Pulls in Millions in Marijuana Tax Revenue. March 11, 2014. Accessed March 17, 2014
- The Washington Post. Gov Beat. Minnesota’s Legislature Approves Medical Marijuana. Could New York Be Next? May 19, 2014. Accessed May 24, 2014
Last updated: 2015-06-07 by Leigh Anderson, PharmD.