Medical Marijuana: The Risks, Benefits, and Legal Status

After decades of contention, the public perception of medical marijuana and recreational cannabis use has begun to change in the United States.

In 2016, 57% percent of the population supported the legalization of marijuana, up from a paltry 32% merely a decade ago [1]. Today, about six-in-ten Americans (62%) say that marijuana should be legalized [2].  Approval for its medicinal usage has grown at an even faster rate, due in large part to expanded awareness of the myriad benefits the plant provides.

There remains no consensus amongst medical professionals or if they advocate and support marijuana for recreational purposes. But more experts are agreeing, rather than contesting, that marijuana has potential health benefits that have not been explored to their fullest extent.

Why Don’t We Know what We Don’t Know about Medical Marijuana?

medical marijuana informationUS federal regulations and restrictions, not to mention social stigmas, have thus far hampered substantial research on marijuana (cannabis). The dearth of scientific study on marijuana’s health benefits is due in no small part to the difficulty of obtaining permission for human trials. The Food and Drug Administration (FDA) has not yet recognized or approved medical marijuana as a treatment for illness and the drug remains classified as Schedule I under the Controlled Substances Act [3-4].

More than 85 cannabinoids and 400 different chemical compounds have been identified within the cannabis plant, but only a tiny handful of these have undergone preliminary testing for medicinal uses. Currently, researchers believe that, among cannabis’ many constituents, CBD and THC hold the greatest medical promise. Others of potential interest include tetrahydrocannabivarin (THCV), cannabinol (CBN), and cannabigerol (CBG). An increasing number of people are calling upon researchers to examine the application of marijuana to various medical conditions as alternative treatment options.

The lack of empirical findings in the field has not prevented doctors from prescribing medical marijuana to patients suffering from a wide variety of ailments like chronic pain, insomnia, nausea, and seizures. In the wake of individual states legalizing medical marijuana, this may seem like a sudden and bizarre shift in medical policy. However, the illicit status of marijuana has a rather short history in the United States, dating back less than a century. Prior to that, marijuana was a normal medical prescription regularly given by doctors, and had been for thousands of years.

Medical Marijuana Throughout History

The earliest written mention of marijuana comes from the 15th-century Chinese tome called Rh-Ya, or the Pharmacopeia, which attributed healing properties to cannabis. Over a dozen centuries earlier, the legendary Chinese emperors Fu Hsi and Shen Nung are said to have likewise extolled the plant’s healthful benefits.

The Chinese were not alone; the ancient Greeks, Egyptians, Persians, and Indians—all major civilizations of the ancient world—used marijuana to treat a variety of ailments, from aches and pains to inflammation and glaucoma. Throughout history, the medical use of marijuana is a pervasive presence, from classical antiquity up through the modern era. It was a mainstay of the apothecary’s cabinet in the middle ages, and by the mid-19th century was commonly prescribed by doctors.

That’s to say nothing of the plant’s other uses throughout history. There is evidence that, during the Exodus, the Israelites may have anointed themselves with cannabis-derived oil for religious purposes, as may have Jesus and his apostles. Shakespeare may have used marijuana recreationally (or, some might argue, artistically). Other writers, such as Oscar Wilde and Charles Baudelaire, were also known to indulge.

Despite its prevalence in history and culture, and its venerable medical reputation, marijuana came under fire in the United States in the early twentieth century. Though the prohibition of marijuana was a decades-long process, the de-legalization of cannabis was fueled prominently by two major factors: xenophobia against Mexican immigrants, who used the plant recreationally, and the sensationalistic “journalism” of William Randolph Hearst, who was more interested in selling papers than in purveying information.

Nearly a century later, a progressive attitude toward marijuana is finally clearing away the cobwebs in the interest of objective, evidence-based scrutiny.

Health Benefits of Marijuana

The suspected and preliminarily confirmed health benefits of marijuana are far too numerous to list in detail. Here are some of the interesting findings that may hold the keys to future medical breakthroughs. For a quick read on the most up-to-date research, be sure to check out statistics on CBD and cannabis here.

Lung Health

Unlike cigarettes, which are known for the damage they do to the lungs, casual marijuana use does not appear to have adverse effects on the human respiratory system. A long-term study published in the Journal of the American Medical Association (JAMA) tested 5,115 young adults for 20 years to observe the effects of marijuana on their lungs. Far from inflicting injury or illness, the study showed that marijuana smoke had “unexpected and apparently positive effects” [5]. Over two decades, while cigarette smokers lost lung capacity, the lung capacity of marijuana uses actually increased (in all but the heaviest smokers, as defined by the study).

Weight Gain

Certain diseases and treatments, particularly cancer and chemotherapy, reduce patients’ appetite and sense of taste. As a result, these patients frequently experience rapid and problematic weight loss. For these ailments, marijuana holds much promise. One study showed that tetrahyrdocannibinol (THC: the main psychoactive component in marijuana) can increase appetite and enjoyment of food in people suffering chemosensory distortions and other, similar disorders [6]. This occurs because THC acts directly on the endocannibinoid system in the human brain, increasing sensitivity to smell and flavor [7].

Eye Health

We have known since the 1970s that THC can effectively treat glaucoma, which involves damage to the optic nerves [8]. One cause of damage is higher-than-normal internal pressure within the eye. THC can reduce this pressure, preventing damage and pain. However, its effects last only a few hours. To be an effective treatment, a person would have to dose multiple times a day, around the clock, which would impair their ability to perform everyday tasks like driving. With continued research into marijuana’s medical potential, these practical limitations may yet yield to more effective glaucoma treatment.

Slowing Alzheimer’s

Researchers at the Salk Institute have found that cannibinoids, like THC, and others found in marijuana can remove proteins from the brain that lead to dementia and Alzheimer’s [9]. Despite the temporary cognitive impairment that THC confers, it can bolster healthy brain function in the long term. There is some promise that marijuana may yield treatments for other ailments associated with aging, but much more research will be required.

Curbing Alcoholism and Addiction

Some might call it substituting one dependency for another, but there is evidence that marijuana helps people reduce or eliminate their abuse of more dangerous substances, such as methamphetamine, alcohol, and illicit pharmaceuticals. In many cases, marijuana helps mitigate severe withdrawal symptoms that occur when fighting addiction. With less intense withdrawals, there can be a lesser chance that those symptoms will lead people to relapse.

Survey studies conducted in California and Canada consistently showed that, of the people questioned, about 75% conceded that using marijuana helped them to avoid alcohol and other, harder substances. Moreover, states that have legalized marijuana for medical use have likewise experienced a 25% decreased incidence of deaths caused by opiate overdose [10].

Inhibiting Cancer

Cancer is the result of malfunction in two types of genes: those that cause cells to multiply, and those that cause cells to stop multiplying. One of these genes, called ID-1, causes cancer to grow and spread. When CBD is introduced to cancerous cells, however, ID-1 switches off, and the cancerous cells stop multiplying [11]. CBD doesn’t cure cancer, but it is capable of stopping the metastasis of aggressive cancers. Despite the intense concentration required for the treatment to be effective, there have been no signs of toxicity in test animals, and researchers hope that clinical trials in humans can begin in the near future.

Reducing Seizures

Seizures occur when there is an alteration in the brain’s normal electrical activity. The cannabinoid receptor CB1 contributes to the onset of seizures, as it plays a role in the excitation and relaxation of neurons in the brain [12]. CBD acts on CB1 receptors, and it has shown substantial effectiveness in reducing the occurrence of seizures in patients with epilepsy [13]. Doctors and researchers have expressed enthusiasm for this promising avenue toward more effective treatments, as have the full third of epilepsy patients who are resistant to anticonvulsant medications.

Pain Relief

Cannabinoids are also known to ease inflammation, and this is especially effective in helping treat one of the major symptoms of autoimmune diseases like multiple sclerosis (MS), lupus, and rheumatoid arthritis: pain. Specifically, CBD and THC bind to pain receptors in the nervous system, preventing users from experiencing the physical discomfort that their ailments produce. CBD has also been demonstrated to ease muscle spasms and stiffness that occur in MS and similar conditions [14]. Obviously, these benefits are not limited to autoimmune disorders; any condition involving inflammation and pain can be treated through the judicious application of cannabinoids.

Easing Anxiety

Cannabis users often tout its relaxing effect on the body and mind, and researchers have conditionally confirmed this [15]. At low doses, THC does act as a sedative, but prolonged or heavy use can actually increase paranoia and anxiety. Nonetheless, the chemical shows promise for reducing stress as long as it isn’t used excessively or consistently.

Effects of Marijuana Use

The immediate effects of using marijuana include short-term memory impairment, lowered blood pressure, increased appetite, dry mouth, and decreased motor coordination. The THC-induced high can alternately produce a sensation of relaxation or it can cause anxiety and paranoia. Higher doses can lead to distorted perceptions, minor hallucinations, and dissociative effects.

The chief hazard of long-term marijuana use is dependence and addiction, which are distinct degrees of substance use. Dependence occurs when the brain adapts to the continual presence of external cannabinoids. In response, it reduces both the production of its own endocannabinoids and the sensitivity of the brain’s endocannabinoid system. Addiction, on the other hand, occurs when a person habitually uses a substance despite its interference in or obstruction of their normal functioning and everyday life.

Studies frequently lump these categories together (since addicted users are also dependent, although a dependent user isn’t necessarily addicted). These studies show that 9% of marijuana users become dependent on the substance, and that number rises to 17% amongst people who begin using it in their teens. When dependent users quit, they experience typical withdrawal symptoms: irritability, difficulty sleeping, cravings, restlessness, among others. These symptoms usually peak in the first seven days of abstinence and can last up to two weeks.

It is worth noting that cultivated strains of marijuana—primarily intended for recreational use but now viable for medical treatment as well—have increased in potency. From the early 1990s to 2014, samples of confiscated marijuana nearly doubled in THC content [16]. Concentrated extracts like cannabis oil and hashish are also widely available. There are currently no definitive findings on how this sort of increased potency affects users.

Marijuana smokers also risk long-term damage to their lungs. While it doesn’t contain the chemical additives found in cigarettes, marijuana tar is thick and viscous, just like that of a tobacco. Because marijuana smokers tend to inhale more deeply and hold the smoke longer, the residue can have a more extensive and damaging effect. Researchers have found little evidence that smoking marijuana over the long term increases the likelihood of lung cancer, but the results were inconclusive regarding heavy users. These hazards, confirmed or potential, are all avoided by users who vaporize flowers or oil, consume cannabinoid-infused foods, or take supplements in pill form.

Because the active components of marijuana work directly on the brain’s extensive endocannabinoid system, they can have repercussions on neural functions and cognition. A study performed at Northwestern University showed that teenagers who used marijuana daily for three years developed abnormal brain structures and functions [17]. In particular, neural structures related to memory withered in a manner reminiscent of schizophrenia-related disorders. These effects were persistent even two years after subjects ceased using marijuana.

Obviously, the effects of long-term marijuana use are poorly understood and require more research. As medical and recreational marijuana become more and more prevalent in the United States, the need for further inquiry becomes more pressing. However, the plant’s accessibility and abundance of users make such investigation much more practical as well.

Legal Status of Marijuana

Currently, 29 of the 50 United States have legalized the use of marijuana in some form, primarily for medical purposes. Despite public opinion and scientific research to the contrary, the federal government maintains marijuana as a Schedule I substance under the Controlled Substances Act, claiming that it has no known medical purpose. Thus, despite local laws that allow for medical use, marijuana is still illegal at the federal level.

At the state level, each legislature has established their own guidelines and regulations for distribution and consumption. Currently, the only states that honor out-of-state medical marijuana cards are Arizona, Nevada, Rhode Island, Maine, New Hampshire, Michigan, and Pennsylvania. This reciprocity extends to having and consuming marijuana; patients may or may not be able to purchase marijuana outside of the state in which they are registered.

Beyond the United States, other nations are taking a scientific and economic interest in marijuana. Israel and Spain have both recently liberalized their marijuana regulations, more or less decriminalizing it to varying degrees. Uruguay, in an attempt to combat cartels, has also legalized marijuana use. Within the United States, seven states and the District of Columbia have legalized marijuana for recreational use—not to mention tax revenue.

Navigating the Medical Marijuana Market

The sheer abundance of types and forms of medical marijuana can be overwhelming, especially for those uninitiated in the ways of the weed.

When it comes to buying flowers, whole plants, and their extracts, medical marijuana patients have three options: indica, sativa, and hybrids. Indica and sativa are categories differentiated by physical structure and resin production. When ingested, each has a different effect. Indica tends to induce full-body physical relaxation and mental drowsiness. Sativa, on the other hand, produces a more cerebral, ebullient sensation in users. Hybrids, bred from indica and sativa, can display a wide range of combined effects.

Based on individual preference and medical exigencies, patients have three broad options for how they consume their medication: inhaling it, applying it topically, or ingesting it.


By far the most commonly known way of consuming marijuana is via combustion. Patients can grind and roll the herb in cigarette papers, or they can smoke it in a pipe, hookah, or other apparatus. These accessories and devices, along with many others, are widely available.

As noted, smoking marijuana may carry certain health risks, and so some patients instead choose to vaporize the plant or its derivatives. Traditional vaporizers heat the vegetable matter or extracts to the point that cannabinoids are released without actually burning the marijuana. This method thereby avoids the hazards associated with smoking.

The rise of electronic cigarettes led to a revolution in vaporizing marijuana. Rather than heating the plant, many users have switched to suspending oils and extracts in glycol. These solutions are vaporized in a discrete, handheld e-cigarette that produces little to no odor nor any ash or desiccated remnants.


In addition to flowers and oils for smoking and vaping, dispensaries carry a wide variety of cannabis-derived products meant for eating. These include baked goods, candies, beverages, and pretty much any other food or libation that can be concocted using marijuana and its derivatives. Patients who prefer to prepare their own edibles can obtain food-grade oils and extracts, or they can forego the pretense of cuisine and just swallow the oil in capsule form.

When marijuana is absorbed through the digestive system, the onset of its effects is significantly delayed. As such, ingesting marijuana is not a means of quick relief from symptoms. Nonetheless, pills, oils, and edibles provide an excellent alternative to anyone who wishes to bypass smoking or vaporizing.

For those who wish to avoid additional calories, tinctures are also available. These are marijuana extracts suspended in alcohol and delivered by dropper onto the tongue. The concentrated cannabinoids are absorbed directly from the mouth into the bloodstream, providing tinctures with the speed of inhalants without the smoke or smell.


The healthful cannabinoids found in marijuana can also be suspended in balms, lotions, salves, and other topical formulae. In this form, cannabinoids are less biologically available for uptake, so topical applications of marijuana don’t produce the same psychoactive reaction as inhaled or ingested forms. Nonetheless, patients have found these solutions effective in providing targeted relief from aches and pains.

Medical marijuana patches are also available, and they work in the same fashion as a nicotine patch: they deliver concentrated, controlled amounts of cannabinoids through the skin and into the bloodstream. The content of these patches is carefully measured, and they provide the most consistent and even means of using medical marijuana. [/page_section]

Marijuana Alternatives

For anyone who, for whatever reason, wishes to entirely avoid marijuana and the plant’s extracts, isolated cannabinoids are available for medical use.

Dronabinol is a synthesized, concentrated THC pill used to treat nausea and vomiting in chemotherapy patients and to reduce pain associated with cancer and AIDS. There is evidence that dronabinol is less effective than organic THC found in marijuana and has more intense side effects.

Concentrated CBD, long overshadowed by THC, is also becoming widely recognized for its medical uses, many of which are described above. It has also proven effective in treating diseases like diabetes, Parikinson’s, lupus, schizophrenia, osteoporosis, and many others. Because CBD is non-psychoactive, it can be obtained easily and legally within the United States in a concentrated form.

Despite the relative dearth of scientific data on marijuana, it has clear potential to upend the medical market by offering natural alternatives to harsh pharmaceuticals. With medical marijuana becoming more common, more information on its health effects will inevitably begin coming to light. As it does, we will gain a better understanding of how cannabinoids affects the human body and how we can best exploit them in the interest of our health.


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[11] McAllister SD, Christian RT, Horowitz MP, et al. Cannabidiol as a novel inhibitor of Id-1 gene expression in aggressive breast cancer cells. Mol Cancer Ther. 2007 Nov; 6(11):2921-2927. doi:10.1158/1535-7163.MCT-07-0371

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