Marijuana Use and Health Effects

Is marijuana addictive?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base:

"Compared to most other drugs ... dependence among marijuana users is relatively rare ... [A]lthough few marijuana users develop dependence, some do. But they appear to be less likely to do so than users of other drugs (including alcohol and nicotine), and marijuana dependence appears to be less severe than dependence on other drugs."

Does using marijuana lead to harder drugs?

According to the National Academy of Sciences' Institute of Medicine: 1999 report, Marijuana and Medicine: Assessing the Science Base:

"There is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs ... There is no evidence that marijuana serves as a stepping stone on the basis of its particular physiological effect ... Instead, the legal status of marijuana makes it a gateway drug."

The World Health Organization noted that any gateway effect associated with marijuana use may actually be due to marijuana prohibition because "exposure to other drugs when purchasing cannabis on the black-market, increases the opportunity to use other illicit drugs."

Is marijuana more dangerous than tobacco?

In a word: no. Marijuana is not more dangerous than tobacco. Research has shown that marijuana causes far less harm than tobacco.

According to the U.S. Centers for Disease Control, tobacco was responsible for 435,000 deaths in 2000, or nearly 1,200 deaths per day. On the other hand, marijuana has never caused a fatal overdose in more than 5,000 years of recorded use.

It is important to note that the act of smoking anything is harmful to the lungs, and in this regard, marijuana is not completely benign. According to Understanding Marijuana (2002), by Mitch Earleywine, marijuana smokers sometimes exhibit symptoms similar to those experienced by tobacco smokers — coughing, wheezing, and bronchitis.

However, these harms can be minimized by ingesting marijuana orally, with devices known as vaporizers, or by using higher-potency marijuana, which reduces the harms associated with smoking while still delivering marijuana's medical benefits.

Other research shows that daily marijuana use does not lead to increased rates of respiratory illness, and that smoking both tobacco and marijuana is worse than smoking just one.

Unlike tobacco, research has never shown that marijuana increases rates of lung cancer or other cancers usually associated with cigarette smoking. In a 10-year, 65,000-patient study conducted at the Kaiser-Permanente HMO and published in 1997, cigarette smokers had much higher rates of cancer of the lung, mouth, and throat than non-smokers, but marijuana smokers who didn't smoke tobacco had no such increase. And in May 2006, Dr. Donald Tashkin of UCLA presented results of a new study showing that even very heavy marijuana smokers had no increased risk of lung cancer.


Has anyone ever died from marijuana?

In all of recorded medical literature, no one has ever died from a marijuana overdose.

In 2001, a detailed examination of the health and psychological effects of marijuana use from the National Drug and Alcohol Centre at the University of New South Wales in Australia noted that marijuana "makes no known contribution to deaths and a minor contribution to morbidity [illness]."

In a 1998 editorial, The Lancet, an esteemed British medical journal, wrote, "On the medical evidence available, moderate indulgence in cannabis has little ill-effect on health."

Can marijuana use cause cancer?

Marijuana smokers do not have an increased risk of premature death or cancer. According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base:

"There is no conclusive evidence that marijuana causes cancer in humans, including cancers usually related to tobacco use. ... More definitive evidence that habitual marijuana smoking leads or does not lead to respiratory cancer awaits the results of well-designed case control epidemiological studies."

Can marijuana cause fertility problems?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base:

"[T]he effect of cannabinoids on the capacity of sperm to fertilize eggs is reversible and is observed at [concentrations] which are higher than those likely to be experienced by marijuana smokers ... The well-documented inhibition of reproductive functions by THC is thus not a serious concern for evaluating the short-term medical use of marijuana or specific cannabinoids."

Can marijuana cause other life-threatening health problems?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base, "Epidemiological data indicate that in the general population marijuana use is not associated with increased mortality."

Does marijuana cause amotivational syndrome?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base, "When heavy marijuana use accompanies these symptoms, the drug is often cited as the cause, but no convincing data demonstrate a causal relationship between marijuana smoking and these behavioral characteristics."

I've heard that today's marijuana is stronger and more dangerous. Is this true?

Claims of a dramatic increase in marijuana potency are commonly based on the assertion that marijuana used in the 1960s and 1970s contained only 1% THC (the main psychoactive compound in marijuana). But, as University of Southern California psychology professor and researcher Mitch Earleywine noted in his book, Understanding Marijuana, these claims are based on very small numbers of samples that may have been improperly stored. Furthermore, marijuana with just 1% THC is not psychoactive  that is, it doesn't produce a "high." So if the 1% figure is true, the drug's rapid increase in popularity was based on marijuana so weak that it wasn't even capable of producing the intended effect.

Earleywine further explained that the moderate increases in potency that have occurred "may not justify alarm. THC is not toxic at high doses like alcohol, nicotine, or many other common drugs. High-potency marijuana may actually minimize risk for lung problems because less [smoke] is required to achieve desired effects." Thus, even if today's marijuana were stronger, it would not be more dangerous.

Effects of Marijuana Prohibition

Are people actually arrested for marijuana?

Yes. An estimated 663,367 arrests were made nationwide for marijuana-related offenses in 2018 — up from 659,700 in 2017 and  653,249 in 2016 — of which 92% were for possession alone. This upsurge in arrests numbers occurred despite the fact that marijuana is legal in 11 states for adults 21 and older. 

On average, one person is arrested for a marijuana-related offense in the U.S. approximately every 48 seconds.

How much does marijuana prohibition cost?

By adding law enforcement costs and depriving governments of the revenue that could be gained by taxing marijuana sales, prohibition costs U.S. taxpayers $41.8 billion per year, according to a 2007 estimate by public policy researcher Jon B. Gettman, Ph.D. The report, "Lost Taxes and Other Costs of Marijuana Laws," is based primarily on government estimates of the U.S. marijuana supply, prices, and arrests.

A more conservative 2005 estimate by Harvard University economist Dr. Jeffrey Miron is still staggering at $10-$14 billion per year.

Wouldn't repealing marijuana prohibition make it easier for teens to buy marijuana?

Marijuana prohibition has not prevented a dramatic increase in marijuana use by teenagers. In fact, the overall rate of marijuana use in the U.S. has risen by roughly 4,000% since marijuana was first outlawed in 1937, and independent studies by RAND Europe and the U.S. National Research Council have reported that marijuana prohibition appears to have little or no impact on rates of use.

Prohibition actually increases teen access to marijuana. Sellers of regulated products like tobacco and alcohol can be fined or lose their licenses if they sell to minors. Prohibition guarantees that marijuana dealers are not subject to any such regulations. Drug dealers don't ask for ID.

Countries that have reformed their marijuana laws have not seen an increase in teen use. Since Britain ended most marijuana possession arrests in 2004, the rate of marijuana use by 16- to-19-year-olds (the youngest group included in government drug use surveys) has dropped. In the Netherlands, where adults have been allowed to possess and purchase small amounts of marijuana from regulated businesses since 1976, the rate of marijuana use by adults and teens is lower than in the U.S.

For more information, please see:
Effective Arguments for Advocates of Regulating and Taxing Marijuana

Medical Marijuana

What conditions can marijuana treat?

People with cancer, glaucoma, AIDS or HIV, Crohn's disease, hepatitis C, and multiple sclerosis have found relief by using marijuana. Marijuana is also used to treat cachexia, anorexia, and wasting syndrome; severe or chronic pain or nausea; seizure disorders (such as epilepsy); arthritis; migraines; and agitation of Alzheimer's disease.

Why not wait for more research before making marijuana legally available as a medicine?

There are several reasons:

  1. The federal government is actively blocking research into marijuana's use as a medicine. In fact, several researchers have filed lawsuits against the federal government, charging it with obstruction for failing to act on an application for approval to grow high-potency, research-grade marijuana at a university facility in Massachusetts. The researchers who filed suit are barred from obtaining research-grade marijuana from other countries, and the poor quality of the federal government's marijuana makes it unfeasible to use in research; thus, without the ability to grow it for themselves, they are unable to conduct research into marijuana's medical use.
  2. There already is ample evidence that marijuana has medical uses.
  3. Even if more research was needed, patients using marijuana should not face arrest and imprisonment while waiting for the results of research that tells them what they already know: marijuana has anti-nausea, anti-spasticity, and appetite-stimulating effects, among many others, that lead to a better quality of life for seriously or chronically ill patients.
  4. In thousands of years of recorded use, marijuana has never been known to cause an overdose death. In fact, it is physically impossible to die from an overdose of marijuana. In comparison, the National Institute on Alcohol Abuse and Alcoholism has reported over 300 deaths per year from accidental alcohol poisoning.
  5. Similarly, long-term marijuana use has never been shown to increase the risk of death or shorten life-expectancy, while the CDC reported in 2004 that excessive alcohol consumption is the third leading cause of death in the U.S., resulting in roughly 76,000 deaths from liver damage, cancers, violence and other causes.

Why shouldn't we wait for new drugs based on marijuana's components to be developed, rather than allowing patients to eat or smoke natural marijuana right now?

Marijuana, in its natural state, provides effective relief to people with numerous medical conditions. Creating pharmaceuticals based on marijuana's medicinal properties is a goal that MPP supports, but not to the exclusion of allowing people to use marijuana in its natural form. There are several reasons why patients should not be forced to wait for marijuana-based pharmaceuticals to reach the market:

  1. It takes years to approve drugs for prescription in the United States. Should patients be forced to go without their medicine while they wait for other drugs to be approved, when marijuana, in plant form, is available now?
  2. Prescription drugs are more expensive than ever before. Because of the rigorous testing requirements to bring a drug to market and to gain regulatory approval, the end product is often quite expensive. And even though natural marijuana can be expensive because it is illegal, it is surely less expensive than the marijuana-based pharmaceuticals that are currently under development.
  3. Marijuana has hundreds, if not thousands, of chemical compounds (as does nearly every other plant). Tetrahydrocannabinol, or THC, is considered the main active chemical in marijuana, and from which the U.S.'s only existing marijuana-based drug, Marinol, is derived. However, science is only just beginning to understand how natural marijuana works. Several other compounds in natural marijuana are being examined for their effects on the human body, and it is believed that marijuana in plant form creates combinations of these compounds that are greater than the sum of their parts. In other words, the many chemicals in marijuana are thought to work together to produce optimal results with minimal negative effects. Much more research is needed, but simply extracting one of the chemicals from natural marijuana does not provide all of the benefits of the whole plant.

Isn't marijuana too dangerous to be used as a medicine?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base, "[E]xcept for the harms associated with smoking, the adverse effects of marijuana use are within the range of effects tolerated for other medications."

If patients were allowed to use medical marijuana, wouldn't non-medical use increase too?

According to the National Academy of Sciences' Institute of Medicine's 1999 report, Marijuana and Medicine: Assessing the Science Base:

"There is a broad social concern that sanctioning the medical use of marijuana might increase its use among the general population. At this point there are no convincing data to support this concern. The existing data are consistent with the idea that this would not be a problem if the medical use of marijuana were as closely regulated as other medications with abuse potential. ... [T]his question is beyond the issues normally considered for medical uses of drugs and should not be a factor in evaluating the therapeutic potential of marijuana or cannabinoids.

"No evidence suggests that the use of opiates or cocaine for medical purposes has increased the perception that their illicit use is safe or acceptable."


Does the passage of medical marijuana laws increase use of the drug among youth?

No. Since the passage of California's medical marijuana law (Proposition 215) in 1996, marijuana use among youth has declined significantly. See MPP's Teen Use Report for more information.

Do people really get arrested for medical marijuana?

In 2012, about 750,000 people were arrested for marijuana possession. The government doesn't keep figures on how many of these people were using marijuana for medical purposes, but if even 1% were, then about 7,500 patients were arrested.

Why is medical marijuana needed if it's already available in a pill form (Marinol)?

When people are vomiting from cancer chemotherapy or AIDS wasting syndrome, it can be extremely difficult to swallow pills. After taking Marinol, patients continue to suffer for a half hour or more before the pill takes effect; smoking marijuana can provide patients with almost instantaneous relief. Additionally, Marinol contains only one of the many therapeutic cannabinoids found in whole marijuana.

How many states allow medical marijuana?

Twenty-four states — Alaska, Arizona, California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington, as well as the District of Columbia — have effective laws protecting qualified patients from arrest and imprisonment for using marijuana under the advice of a physician.

A number of other states have passed symbolic, non-binding laws pertaining to medical marijuana. For more information on marijuana laws by state, please visit MPP's State-by-State Medical Marijuana Laws: How to Remove the Threat of Arrest.

How do state medical marijuana laws work?

Because 99% of marijuana arrests are made at the state level, well-written state medical marijuana laws effectively protect patients, despite federal hostility.

In states without effective medical marijuana laws, patients are treated as criminals. They may face an insufficient supply of medicine due to its prohibition-inflated price or scarcity; impure, contaminated, or chemically adulterated marijuana from the underground market; arrests, fines, court costs, property forfeiture, incarceration, probation, loss of financial aid for education, loss of employment, and criminal records.

Don't state-level medical marijuana laws put states in violation of federal law?

There is no federal law that mandates that states must enforce federal laws against marijuana possession or cultivation. States are free to determine their own penalties — or lack thereof — for drug offenses. State governments cannot directly violate federal law by giving marijuana to patients, but states can refuse to arrest patients who grow or acquire their own medicine.

Further, on October 14, 2003, the U.S. Supreme Court declined to hear Conant v. Walters, letting stand an appellate court ruling that barred the federal government from punishing physicians who recommend medical marijuana to patients. By refusing to hear this case, the Supreme Court eliminated any doubt that states have the right to protect medical marijuana patients and their physicians under state law. Some people mistakenly believe that the 2005 U.S. Supreme Court decision in Gonzales v. Raich invalidated state medical marijuana laws, but that is not the case. The decision simply maintained the status quo as it has existed since California voters passed Proposition 215 in 1996: States may protect medical marijuana patients from arrest under state law, but those laws don't give patients immunity from federal prosecution. Shortly after the Raich decision, Montana Attorney General Mike McGrath told the Helena Independent Record, "We still have a valid law." Officials from every medical marijuana state have made similar determinations.

Shouldn't we go through the FDA approval process instead of passing medical marijuana bills and initiatives?

In its 1999 report on medical marijuana, the Institute of Medicine (IOM) commented on the difficulty of doing marijuana research: "Some drugs, such as marijuana, are labeled as Schedule I in the Controlled Substances Act, and this adds considerable complexity and expense to their clinical evaluation. ... In short, development of the marijuana plant is beset by substantial scientific, regulatory, and commercial obstacles and uncertainties."

As is mentioned by the IOM, the FDA's bureaucratic approval process would take many years and cost millions — and possibly billions — of dollars. Because the marijuana plant cannot be patented, there is no economic incentive for pharmaceutical companies to invest in getting FDA approval for marijuana. Seriously ill people who find relief through marijuana (and whose doctors approve its use) should not be forced to face arrest while waiting for this process to start or be completed.

What major organizations support medical marijuana?

  • American Medical Association
  • American College of Physicians
  • American Nurses Association
  • American Public Health Association
  • Lymphoma Foundation of America
  • Leukemia & Lymphoma Society
  • Epilepsy Foundation
  • American Academy of HIV Medicine
  • National Multiple Sclerosis Society
  • Episcopal Church
  • Presbyterian Church USA
  • Consumer Reports magazine
  • American Federation of State, County and Municipal Employees

And many, many more ...

All either support legal access to medical marijuana or have directly acknowledged that marijuana can have legitimate medical uses. (The American Medical Association, formerly opposed to medical marijuana, officially changed its position to neutral in 1997; the AMA endorses a physician's right to discuss marijuana therapy with patients.)

For more information, please see:
Effective Arguments for Medical Marijuana Advocates