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Medical Cannabis: History, Benefits, Use and Effects

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Medical marijuana or medical cannabis is a cannabinoid drug that has been synthesized from the cannabis plant for use in medical treatment of patients in many countries around the world. While there are many arguments on the benefits of cannabis in medical applications, the medicine form has not been fully tested for its full potential due to the many restrictions in both production and governmental regulations in the various countries where it has been legalized for use.

Complete medical benefits are not fully clear

There is limited evidence available that the use of medical cannabis can help to reduce nausea and vomiting during chemotherapy treatments for cancer, and can improve the appetites of people with HIV/AIDS. It is also known that it can severely reduce chronic pain and muscles spasms in patients with severe muscular injuries. And while there is some evidence to suggest that the short-term use of cannabis can increase the risk of some minor side effects, the long-term effects are yet unclear. More research still needs to be completed before such quantifiable evidence can be released. However, major concerns among medical practitioners include memory and cognitive problems, the risk of addiction, as the addictive qualities are neither proven nor disproven yet, and the risk of it accidentally being taken by children. The effects on children under 12-years-old are unconfirmed due to restrictions on testing.

How to administer medical cannabis

As a drug, cannabis can be administered in many ways, including using lozenges, dermal patches or oral/​dermal sprays, as well as by vaping a synthesized liquid, smoking of the dried buds, eating cannabis-inclusive foods (where the cannabis has been cooked into the food), and ingestion in the form of medical capsules.

History of medical cannabis from past to present

Ancient times

Cannabis has been used throughout history as both medicines and recreational or psychoactive use. Its origins are believed to have been in Taiwan around 10,000 years ago, where hemp seeds were used as food. It is fair to believe that they would also have discovered the medicinal uses of the plant. Pharmacologist and emperor, Shen Nung, wrote a book that included some of the medical benefits of cannabis in 2737BCE, and he recommended the drug for several illnesses and ailments, including gout, rheumatism, constipation, and absentmindedness. Ancient texts from India also confirm the use of cannabis for its psychoactive properties and its use in medical treatment, including as a pain relief during childbirth. And in ancient Egypt and ancient Greece, there is extensive evidence of its use, and was even mentioned in the famed Ebers Papyrus from 1550BCE. In more modern times, there is extensive evidence of its use in medicine right up to the late 18th century.

Throughout history, cannabis has been used for its medicinal properties, and its use is believed to have started over twelve thousand years ago in Asia. With hemp seeds being a natural part of Asian foods, ancient physicians soon discovered that the plant had many other useful properties, especially in the areas of medicines and narcotics. As far back as 2900BCE, there are texts that quote the use of Ma”, the Chinese word for cannabis, as a popular medicine that possessed both yin and yang. In the 27th century BCE, the Emperor Shen Hung wrote of the medicinal properties of cannabis in his works. Considered to be the father of all Chinese medicine, his writings included the fact that cannabis was useful in the treatment of gout, constipation, rheumatism, and forgetfulness.

Chinese women creating medicine from cannabis plants. (herb​.co)

In Egypt, in the 12th century BCE, cannabis was a popular medicine for treating glaucoma, inflammation (hemorrhoids) and other ailments, and pollen from the cannabis plant was found in the wrappings of the mummy of King Ramesses II when his tomb was finally opened in 1995. There have also been extensive mentions of its use in several ancient papyri spanning a period of over a thousand years, including the Ebers Papyrus from 1550BCE, the Ramesseum III Papyrus from 1700BCE, the Berling Papyrus, that is dated from around 1300BCE, and the Chester Beatty Medical Papyrus from 1300BCE.

Scripture depicting Ancient Egyptians using cannabis. (herb​.co)

In India in around 1000BCE cannabis was used as an anti-phlegmatic and anesthetic, and was administered in milk. India has always had close ties with the use of cannabis as a medicine, and bhang”, the medicinal name for the cannabis plant in India, has long been a regular medicine for many ailments. Ancient Indian text shows that they also used bhang for the treatment of dysentery and sunstroke, as well as to quicken digestions and for other stomach ailments. In around 600BCE, an Indian medical work known as the Ayurvedic treatise of Sushrita Samhita cited cannabis as a cure for leprosy.

On and on throughout history, there have been medical references to the use of cannabis as a healing medicine. In Greece, it was used for earaches and inflammation, and the Greek physician, PedaniusDioscorides, who was a doctor with the Roman Legions, added it to his book entitled De Materia Medica (On Medical Matters) in AD 70, which became the most important medical tome for the next 1500 years. Its medicinal properties are even extolled by the Roman scientist and historian, Pliny the Elder, as being used to ease cramped joints, gout too and similar violent pain” in his book, Naturalis Historia, in AD 79.

In ancient Persia, the famous polymath, Avicenna, (Ibn Sina)wrote about the medicinal properties of cannabis many times in his works, and his contributions to medicine were hugely influential throughout Europe during the medieval and renaissance period. His texts tell of his use of the whole plant for its medicinal properties, using seeds, roots, and leaves for both internal and topical treatments. His works often refer to it as the juice of cannabis leaves”, and he would mix it with other herbs and plants to make concoctions to treat a range of illnesses. The works of Avicenna were so influential in early western medicine that cannabis was referred to in Brice Bauderon’s 17th-century medical work, The Pharmacopoeia of Bauderon, as Cannabis ex Avicenna”.

Modern times

In modern medicine, cannabis has been used regularly to treat muscle spasms, stomach cramps, and general pain since the early part of the 19thcentury. Its introduction to western medicine was attributed to the Irish physician, William Brooke O’Shaughnessy, who was famous for his work in pharmacology, chemistry and his research that led to intravenous therapy. After his return from India, he began the first ever clinical trials into the medicinal benefits of cannabis, using the recipes he had learned from the Ayurvedic physicians. In 1839, he produced the first concise case studies of his treatment of patients suffering from rheumatism, cholera, tetanus, and hydrophobia, which showed that the cannabis tinctures he developed had significant effect on the ailments. And the personal physician of Queen Victoria, Sir Robert Russell, wrote extensive papers on the benefits of cannabis and recommended its use as a tincture in the treatment of dysmenorrhoea (menstrual cramps).

O’Shaughnessy’s clinical trials produced results that had many physicians of the time clamoring to try this new wonder drug”, and between 1839 and 1900 over 100 papers were written on the subject, as chemists worked to identify and isolate the active principles of cannabis, a goal not achieved until 1964, by Dr. Raphael Mechoulam. A Professor of Medicinal Chemistry at the Hebrew University of Jerusalem, he was the first to identify delta-9-tetrahydrocannabinol (THC), as the main psychoactive component of cannabis. He was also the first to synthesize THC.

In 1850, cannabis was included into the United States Pharmacopeia, the official government authority for all prescription medicines in the U.S. Cannabis was listed as a treatment for numerous illnesses and ailments, including neuralgia, tetanus, typhus, cholera, rabies, dysentery, alcoholism, opiate addiction, anthrax, leprosy, incontinence, gout, convulsive disorders, tonsillitis, insanity, excessive menstrual bleeding, and uterine bleeding. Pharmaceutical companies patented marijuana tinctures which were sold by pharmacists under prescription from doctors. It was removed from the US Pharmacopeia in 1942, finally losing the mantle of being a legitimate medicine.

In the 1970s, cannabis was synthesized for use as a drug in the United States, and approved by the Food and Drug Administration (FDA) under the name Marinol. In 1978, a new program was established in the United States and run by the federal government. The Compassionate Investigational New Drug (CIND)program allowed a small number of people with severe illnesses to use medical marijuana as a treatment. This small group of people was suffering from illnesses that included Multiple Sclerosis, AIDS, Nail-patella Syndrome, Multiple Congenital Cartilaginous Exostoses, and Glaucoma. Of the ten patients that were prescribed with medical cannabis in the group, four are still alive and are still classed as active participants in the program.

In 1990, a senior investigator at the National Institute of Mental Health, discovered a connection between cannabis and certain receptors in the brain. This discovery helped scientists to better understand the effects of cannabinoids, which occur when Cannabis-based THC binds with these cannabinoid receptors in the brain. Cannabinoids (THC and CBD)are the chemical compounds produced from cannabis flowers, which can imitate the natural compounds found in the body, called endocannabinoids. These compounds work to maintain internal stability and health, and mediate communication between cells. Where there is a problem with endocannabinoids, unpleasant symptoms and physical complications can occur, which can be treated by the introduction of THC or CBD to the system.

On November 5, 1996, California became the first state to legalize cannabis for medical use. Proposition 215, as it was known, was an initiative to allow patients and primary caregivers to possess and cultivate cannabis for the treatment of AIDS, cancer, muscular spasticity, migraines, and several other disorders, with a physician’s recommendation. But it was not until late in 1998 that three other states approved the use of medical marijuana, with ballots in Alaska, Oregon, and Washington. By the middle of 2014, 23 states plus the District of Columbia had passed laws allowing the use of medical marijuana, with three more states joining after the elections in November 2016.

22 years after its initial inception in 1978, the Compassionate IND program produced its only study on the effects of cannabis treatment on their selected patients in January 2000. The study showed that, despite the cannabis being provided by the government being a crude mixture of leaf with abundant stem and seed components”, there were definite benefits of cannabis medication in those patients. The conclusion of the study stated that cannabis smoking, even of a crude, low-grade product, provides effective symptomatic relief of pain, muscle spasms, and intraocular pressure elevations” and that clinical cannabis patients are able to reduce or eliminate other prescription medicines and their accompanying side effects.” However, despite this conclusive evidence of the benefits of marijuana in cases such as glaucoma, and the 27 states and districts that have legalized its use for medical purposes, the federal government refuses to change its stance on the medical use of cannabis.

Medical cannabis use in modern society and cultures

Legal status

The legal status of medical cannabis use varies around the world, from illegal to legal, and is dependent on the country in which it is being used. There is no internationally recognized legal status for both medical and recreational use of cannabis, although the number of countries where it is being legalized or decriminalized is continuously growing. As of this time, the countries where the medical use of cannabis or a THC preparation (capsule medication) is legalized are:

The United Nations (UN) Single Convention on Narcotic Drugs (SCND) lists cannabis in Schedule IV, giving it special restrictions. According to Article 2 of the SCND, Schedule IV allows as follows:

A Party shall, if in its opinion the prevailing conditions in its country render it the most appropriate means of protecting the public health and welfare, prohibit the production, manufacture, export and import of, trade in, possession or use of any such drug except for amounts which may be necessary for medical and scientific research only, including clinical trials therewith to be conducted under or subject to the direct supervision and control of the Party.”

This means that the Convention allows individual countries to outlaw cannabis if they so wish, while still allowing its use in research and medical use as they see fit. It also means that any country or state allowing the use of medical marijuana operates a licensing system for all growers, manufacturers, marketers, and distributors. The total volume of cannabis should not exceed that required for their scientific and medical purposes.


Distribution of cannabis for medical use varies from country to country, and in the U.S., users can either grow it themselves or buy it from listed dispensaries. Vending machines are now being used in some states, and are being planned for use in Canada, and there is even a mobile app where you can order more in the San Francisco area.

As there is no full FDA approval for cannabis medication yet, medical insurance will not cover its cost of purchase for users.This is hoped for in the future if the federal government legalizes its use and it is approved by the FDA.

Recreational use

The recreational use of cannabis is still illegal in many countries around the world, with only a handful allowing it for personal, recreational consumption. However, this list of countries allowing the use of cannabis for medical and recreational purposes is increasing, as the research into the plant’s use gets deeper, and the minimal adverse effects are legally recognized.

Brand names

In the U.S. there are only two brand names for medical cannabinoids that are approved by the FDA, the same number as in Canada, and only nine other countries have approved the use of cannabinoids in medications.


There has been a lot of research into the uses and benefits of cannabis the in majority of countries where studies can be conducted. However, there is only limited study on certain aspects and parts of the plant and its properties, and no study of the whole plant has ever been initiated. Despite the new rules within the compliant U.S. states, the nation is not advancing in the study and research of the cannabis plants benefits due to the massive amounts of red tape involved in getting a study off the ground. Approvals are needed from the FDA, the Drug Enforcement Administration (DEA), and NIDA. Moreover, any other government agency involved in the prohibition or research of cannabis could halt the entire project at any time, especially the government’s federal law enforcement agencies.

There is currently ongoing research around the world into the use of cannabis and cannabinoids in the treatment of cancer, dementia, diabetes, epilepsy, glaucoma, Tourette syndrome, and many other conditions. However, the research into its use as a beneficial medical drug is ongoing, and there are yet inconclusive results for the majority of studies.

In cancer, it is believed that the use of cannabis could have positive effects, and laboratory experiments have shown some small amount of anti-cancer effects from cannabinoids. However, there has been no full human trial or clinical study yet, and much of the current evidence” available on the internet is misleading” according to Cancer research UK. Nor is there any evidence that using cannabis can help reduce the risk of getting cancer. More research is still needed in these areas.

The same is still also true in cases of dementia, diabetes, epilepsy, and Tourette syndrome, although the studies in the latter have produced very conflicting results. Glaucoma has also been ruled out as a beneficiary of medical cannabis due to the side effects, the short duration of effectiveness, and lack of evidence of any long-term effects.

Studies and research are also ongoing for illnesses such as Huntington’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, bipolar disorder, digestive diseases, and many other illnesses. However, in the case of multiple sclerosis (MS), patients who took the substance orally or as a dermatological spray showed some relief in the normal muscle stiffness, and there is evidence to support it. The American Academy of Neurology — which has previously stated that the scientific evidence to support the use of cannabis in any form as a medicine for treating or alleviating neurological disorders was weak to failing – has published new guidelines on the use of cannabis tablets and sprays for the treatment of MS sufferers.

In psychiatry, studies have shown that cannabinoids such as cannabidiol, have shown high potential in the treatment of several psychiatric conditions, including depression, anxiety, and psychosis.

Marketed cannabis-based drugs

Cannabis elements are now being used in drugs, in the form of Tetrahydrocannabinol (THC) and Cannabidiol (CBD). While THC is the ingredient in cannabis that works on the cannabinoid receptors in the brain, CBD is the part of the plant that produces muscle relaxants, and works on the cannabinoid receptors in the body. These drugs are now available by prescription in the United States:

Several other drugs are currently in either clinical trials or are still in the research and testing stages.

Medical uses of cannabis and cannabinoids

Medical cannabis has been proven to have several beneficial uses in medicine for the treatment of illnesses and ailments. The evidence in many cases is still undergoing conclusive testing, but studies are showing that its use in the treatment of several major illnesses has a beneficial effect to the patients, as well as treating many of the symptoms of the ailments. Testing for the full potential benefits of marijuana is still ongoing. While many other organizations have varied views on the medical use and legalization of cannabis, the FDA has stated that cannabis does not meet the criteria for accepted medical use due to lack of evidence regarding safety and the high risk of abuse”.

Nausea and vomiting

The use of medical cannabis for chemotherapy patients has been rated as having a significant effect in chemotherapy-induced nausea and vomiting (CINV) produced by the treatment. Studies have shown that cannabinoids can be more effective than traditional medications such as prochlorperazine, promethazine, and metoclopramide in controlling CINV.


The evidence that cannabis can be safely used in the treatment of HIV/AIDS patients for anorexia-associated symptoms is inconclusive and has been tainted by bias, small testing sizes, and the lack of conclusive, long-term data. However, it has been proven that cannabis can improve the appetites of HIV/AIDS patients to the degree where they are more easily able to eat and retain some intake of the energy and nutrients needed.


The treatment of chronic pain using cannabis has been proven somewhat effective, including neuropathic pain, fibromyalgia, and rheumatoid arthritis. A 2011 study showed that it was generally safe for use for chronic pain relief in the short-term, though there is very weak evidence of the benefits in cancer patients. However, smoked cannabis has shown better results than cannabinoids in reducing chronic, non-cancer pain in the short-term for around 20 percent of sufferers. In January 2017, a report by the U.S. National Academy of Science, Engineering, and Medicine showed there was substantial evidence to prove that cannabis was effective in controlling chronic pain in adults.

Neurological problems

The studies around neuropathic pain relief are not yet clear, especially in severe cases of multiple sclerosis (MS), epilepsy, and motor neurons disease. A combination of cannabinoids with other medications has shown some relief in spasticity though it does not give significant changes in the ailments.

Posttraumatic stress disorder and depression

The evidence that cannabis can help with posttraumatic stress disorder (PTSD) symptoms is very tentative yet, but a study carried out by the University of Buffalo into the uses of cannabinoids in depression showed that it can stabilize moods and combat severe depression

Parkinson’s disease

Research from the Tel Aviv University, in Israel, has shown that cannabis can reduce the pain and tremors of patients suffering from Parkinson’s Disease.

Alzheimer’s disease

A study produced by the Scripps Institute on the effects of cannabis on Alzheimer’s disease patients showed that the use of THC can reduce the progression of the disease. The use of THC can limit the formation of the amyloidal plaques in the brain that cause the illness by inhibiting the enzyme that produces them.

Multiple Sclerosis (MS)

A 2012 study into the benefits of cannabis in MS patients showed that the drug can reduce the painful muscle contractions related to the disease (muscle spasticity) and relieve the pain in the lumbar region caused by the myeloid lesions on the spinal cord.


As was shown in the report from the Compassionate IND program, which contained four patients with glaucoma, cannabis has the effect of reducing intraocular pressure. More recent studies have shown that, in clinical trials, glaucoma patients experience relief on average within two hours of the administration of oral compounds of THC and CBD.

Adverse effects of cannabis and marijuana use

Medical use

There is still very little conclusive evidence to suggest that cannabis and marijuana use is safe, although the typical adverse effects are not considered serious. The main adverse effects include tiredness, dizziness, cardiovascular, and some minor psychoactive effects. Tolerance to these effects can develop over a period of a few weeks to months, and the amount of cannabis used for standard medical treatments is believed to not cause permanent cognitive impairment in adults. However, long-term use in adolescents should be avoided, as they are more susceptible to impairment.

Recreational use

In the United States, and many other countries around the world, recreational use of cannabis is prohibited and illegal. There are some acute effects that have been shown to appear in regular users who smoke the plant, both on its own and with tobacco. Anxiety, panic attacks, reduced attention spans, loss of memory during intoxication, and minor psychotic episodes are well documented and usually resolve within minutes or hours of use. Reports of extended symptoms have been relatively small in comparison with the 455,000 estimated annual emergency room visits associated with cannabis use. While the use of cannabis must be implicated in the visit to an emergency room, it is often not the main cause of the visit. Most emergency room visits for drugs involves multiple drug abuse, and in 129,000 listed cases, only one was implicated as directly caused by cannabis.

Chronic use

Chronic use of cannabis as a recreational drug may cause severe effects such as bronchitis, subtle impairments in memory and attention, and a cannabis dependency syndrome. In most adults, any cognitive impairment is not persistent, and fades after abstinence from the drug. There have been very limited numbers of studies that have focused on the effects of smoking cannabis on the human respiratory system. While prolonged use can bring on the symptoms of acute bronchitis, it has shown no significant anomalies in lung functions.


While cannabis smoke is known to contain over fifty known carcinogens, including nitrosamines, reactive aldehydes, and polycylic hydrocarbons, it is not believed that light to moderate use increases the risk of airway or lung cancer. The risks of pulmonary complications are far lower in cannabis smokers than in cigarette smokers, and the carcinogens are not present when consumed using a vaporizer, in pill form, or when added to foods.

Cardiovascular disease

There is a major amount of suspicion surrounding the contribution of cannabis smoking to cardiovascular disease. In the studies that have been done, mainly outside the U.S., 97% of cases also smoked tobacco, so there was no formal association of cardiovascular disease with cannabis smoking.


The use of cannabis does not usually cause withdrawal symptoms in normal users when abstaining, and only 42.2 percent of heavy users showed any signs of withdrawal symptoms when quitting. Symptoms shown were normal symptoms, similar to quitting tobacco, such as cravings, irritability, boredom, anxiety, and sleep problems.

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