Hemp has been used for its virtues, particularly against pain, for thousands of years. A survey, published in February 2019 on the website of theNational Institutes of Health, highlights that more than half of these prescriptions were prescribed to relieve the condition that affects one in five people: chronic pain.

How do cannabinoids affect pain?

Figures (1)

After California in 1996, there are now thirty-three federal states (plus the District of Columbia) in the United States. United States that authorize the use of cannabinoids to relieve patients with a wide variety of pathologies (ten federal states authorize the recreational use of cannabis). To qualify for authorization, future users must meet certain admission requirements, which vary according to the policy applied in each of these states.

In order to verify the admissibility of these prescriptions, theNational Institutes ofHealth (NIH) carried out a study based on records dating back to 1996. Only around twenty states provide this information, which is sometimes erroneous. This lack of correspondence with reality stems from the fact that this information is provided on a voluntary basis.

The results conclude that chronic pain is the main reason for prescribing cannabinoidsfrom 1996 to 2016, with an average of 62.2%. The other most common qualifying conditions are muscle spasms due to multiple sclerosis, chemotherapy-induced nausea and vomiting, post-traumatic stress disorder and cancer.
For these different pathologies, nine out of ten people reported that cannabinoids had a relieving effect on their symptoms.

Finally, this study highlights the need to standardize data collection for these prescriptions. The non-recognition of cannabinoids at federal level is holding back the development of research, and calls on theUnited Nations (UN) to reclassify cannabis in the schedule of the Single Convention on Narcotic Drugs recommended in February 2019 by World Health Organization (WHO).
L'United Nations (UN) has postponed the vote to March 2020, having originally scheduled it for March 2019.

Chronic pain (2)

Pain is " an unpleasant sensory and emotional experience associated with actual or potential tissue damage ". Individual and subjective, it is specific to each person, which makes it difficult to define a scale of pain intensity.

Its primary role is to signal and protect the human body via nociceptors (peripheral pain receptors). They pick up this information and transmit it via sensory nerves to the spinal cord.
On its way up the spinal cord, the signal crosses the thalamus and then the cerebral cortex of the brain toregister the pain information. This " ordinary " (or nociceptive) pain is more commonly referred to as acute pain.

When pain is persistent, lasting more than three months despite the disappearance of the initial cause, we speak of chronic pain. The same applies to recurrent pain, which occurs periodically.
In such cases, pain no longer fulfils its role as an alarm signal and protector of the organism, and thus becomes a disease in its own right, which can be characterized as one of three types of pain:

• Pain due to excess nociception (or inflammatory pain)
• Neuropathic pain
• Dysfunctional pain

   

Chronic pain leads to psychological difficulties (depression, anxiety, insomnia...), as well as physical pathologies and social withdrawal. Pain thus handicaps patients' daily lives, both in their professional careers and in their personal lives. Almost 20% of the population suffers from pain, a figure set to rise with the ageing of the population and the lack of research into the causes of these pathologies.

The story (3)

Hemp has been used in traditional Chinese medicine for 4700 years, with the first written records of its use as a medicinal plant. The first general anaesthetic to be used during surgery was performed by the legendary Hua Tuo in the 2nd century, using his famous mafeisan, otherwise known as " boiled hemp powder ".

From 1500 to 200 B.C., cannabis was used as a medicine in Egypt, India, Greece and the Mediterranean region to treat a wide range of pathologies, including pain. In Persia, cannabis was glorified as the most important medicinal plant, according to the sacred book of the Mazdean religion, theAvesta.

In the early days of Islamic medicine, cannabis was a controversial plant. Defined by some as a deadly poison, althoughno case of death has yet been attributed to it, and by others as a plant with exceptional virtues. In the 9th century, a Persian physician, Shapur Ibn Sahl, relieved his patients' headaches with " cannabis juice ", which he treated by inhalation.

In the 19th century, Dr Lynch treated a patient suffering from neuropathic pain in the head and eyes with " a tincture of Indian hemp ". According to his results, the pain disappeared after two days. He demonstrated the effects of cannabis on another patient suffering from arm neuralgia, using " indica tincture ".
In 1887, a Philadelphia medical professor, Dr. Habart Amory Hare, wrote an article on the benefits of cannabinoids compared with opioids, which have undesirable effects such as nausea, sedation (calming action) and dependence.

In 1925, the League of Nations authorized the use of hemp and its derivatives for medical purposes only. After mid-century studies focused on the psychoactive effects of cannabis, the Single Convention on Narcotic Drugs Single Convention on Narcotic Drugs in 1961 as a drug in its own right, on a par with cocaine, LSD andheroin.
Medical research into the potential uses of uses of cannabinoids in pharmacopoeia to alleviate, or even cure, various pathologies such as pain is therefore held back, in total ignorance of previous evidence on these virtues, recognized for millennia.

Research

In 2013, armed with the authorization to prescribe phytocannabinoidsDr. Sunil K. Aggarwal studied the effect of cannabinoids on his patients suffering from chronic pain such as myofacial pain, neuropathic pain, back pain, arthritic pain, fibromyalgia and visceral pain. Once the dosage appropriate to each individual's body, patients experienced relief from their symptoms.(4)

Chronic pain is regularly treated withopioids, despite their lack of efficacy in relieving certain types of pain.
Drs. Hohmann and Russo observed in 2013 that cannabinoidsas an adjunct to standard treatment, reduce the dosage, tolerance and dependence associated with opioids(5) In 2004, the same Dr Russo had already studied the role of endocannabinoids on chronic pain conditions such as migraine, fibromyalgia and functional colopathy, showing that taking phytocannabinoids these diseases by rebalancing the endocannabinoid endocannabinoid system.(6)

The endocannabinoid system system also plays an essential role in pain signaling andintensity. Cannabinoids (endogenous and exogenous) produce analgesic and antinociceptive effects. They also modulate pain signal transmission between the spinal column and the brain, and reduce pain sensitivity.

The latest study on chronic neuropathic pain published in August 2018 and led by Dr. Gabrielle Gobbi, highlights theaffiliation between cannabidiol (CBD) and serotonin neurotransmitters by triggering receptors, playing a role onanxiety (5-HT1A) and pain (TRPV1).(7)

Cannabidiol (CBD), a phytocannabinoid with no psychoactive effects, has historically been less studied than its tetrahydrocannabinol (THC) counterpart.
The focus of research over the last few decades, clinical studies on cannabidiol (CBD) have been more thanencouraging, revealing its many virtues inthe treatment of pain, nausea,vomiting,epilepsy, withdrawal,anxiety, muscle spasms induced by multiple sclerosis, post-traumatic stress...  

Sources

1 : KF Boehnke, S Gangopadhyay, DJ Clauw, RL Haffajee. Qualifying Conditions Of Medical Cannabis License Holders In The United States.

2 Patrick Gunti. Chronic pain: when pain becomes disease.

3 : Michael Backes: Medical Cannabis - What you need to know...

4 Sunil K. Aggarwal. Cannabinergic Pain Medicine: A Concise Clinical and Survey of Randomized-Controlled Trial Results.

5 : Ethan B. Rosso and Andrea G. Hoffmann. Role of Cannabinoids in Pain Management

6 Ethan B. Rosso. Clinical Endocannabinoids Defiency (CECD): Can This Concept Explain Therapeutics Benefits of Cannabis in Migraine, Fibromyaligia, Irritable Bowel Syndrome and Other Treatment-Resistant Conditions?

7 De D Gregorio, RJ McLaughlin, L Posa, R Ochoa-Sanchez, J Enns, M Lopez-Canul, M Aboud, S Maione, S Comai, G Gobbi. Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain.