Key Definitions
Introduction
The extent to which Cannabis was used by humans throughout early history is a complete mystery as the plant’s usage predates writing. Archaeologists have traced the use of Cannabis as far back as 4000 BC, with medical applications being written about Cannabis as far back as 2737 BC (Amar, 2006).
The following sections aim to provide evidence for the medical applications of Cannabis by only examining the findings of properly controlled clinical trials from 1975. Some of the clinical studies refer to registered medications that consist of one or more constituents found in Cannabis. Note that none of these medications are currently registered in South Africa. The following is a list of some of the registered medicines:
- Dronabinol or Marinol®: an oral capsule that contains a synthetic version of (-)-delta-9-trans-tetrahydrocannabinol (THC).
- Nabilone or Cesamet®: an orally administered drug that contains a synthetic version of THC.
- Nabiximols or Sativex®: an oromucosal spray that contains THC and cannabidiol (CBD) in a 1:1 ratio.
- Cannador®: an oral capsule that contains whole Cannabis plant extract and has a THC to CBD ratio of 2:1.
- Cannabidiol or Epidiolex®: a 98% oral CBD solution that consists of pure plant-derivatives.
Antiemetic Effect
The antiemetic effect of Cannabis is related to the symptoms of nausea and vomiting that are caused by Cancer chemotherapy. The following is a summary of findings across 30 controlled clinical studies:
- Nabilone showed superior antiemetic effects when compared with conventional antiemetics (e.g., prochlorperazine). The studies also indicated that patients favoured nabilone over other antiemetics (Amar, 2006) (Legare, et al., 2022).
- Dronabinol showed equivalent to greater antiemetic effects when compared with conventional antiemetics (e.g., chlorpromazine) when treating delayed chemotherapy-induced nausea and vomiting (CINV) (Amar, 2006) (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
Appetite Stimulation Effect
The appetite stimulation effect of Cannabis is related to the loss of appetite associated with anorexia, cancer cachexia, human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). The following is a summary of findings across 8 controlled clinical studies:
- Orally administered THC and smoked THC (namely Cannabis) stimulated the appetite and slowed or stabilised weight loss in advanced cancer patients (Amar, 2006). Oral THC also increased taste and smell perception, macronutrient preference, appeal of foods, relaxation and sleep quality in cancer patients undergoing chemotherapy (Kowal, et al., 2016) (Legare, et al., 2022).
- HIV patients using smoked Cannabis and oral dronabinol increased their food intake throughout the day (Hazekamp & Grotenhermen, 2010). Inhaled Cannabis was also found to increase appetite hormones in the blood stream (Kowal, et al., 2016).
Analgesic Effect
The analgesic effect of Cannabis relates to the treatment of acute (e.g., postoperative pain) and chronic pain (e.g., cancer and neuropathic pain). The following is a summary of the findings from over 20 controlled clinical studies:
- Oral and sublingual THC and THC/CBD mixtures have been found to exhibit analgesic effects in moderate to high doses (10-20 mg) for chronic pains (Amar, 2006) (Hazekamp & Grotenhermen, 2010).
- Patients with chronic therapy-resistant pain and patients with fibromyalgia found that Nabilone decreased pain and increased their quality of life. Note that Nabilone in conjunction with standard therapies, may offer greater value for pain management than Nabilone alone (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- Dronabinol in conjunction with opioids contribute to significant pain relief and quality of sleep in patients with chronic noncancer pain (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- Smoked Cannabis can be used to help with neuropathic pain. Smoked Cannabis was also found to reduce daily pain significantly in patients suffering from HIV-associated sensory neuropathy (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- Rheumatoid arthritis patients found a statistically significant improvements in pain on movement, pain at rest, quality of sleep and inflammation when taking Sativex. Sativex was also found to be effective in relieving peripheral neuropathic pain when taken in conjunction with other analgesics (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- Use of THC/CBD oromucosal sprays in conjunction with standard opioid therapy showed reduced pain intensity scores amongst patients with neuropathic pain (Kowal, et al., 2016).
- Sativex was found to be effective in reducing pain and sleep disturbances in patients with multiple sclerosis (MS) (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- THC/CBD oromucosal spray produced clinically significant improvement in average daily MS associated neuropathic pain (Kowal, et al., 2016).
- Oral THC was found to be as effective for pain relief as diphenhydramine in patients of spinal cord injuries (Kowal, et al., 2016).
Treatment of Multiple Sclerosis
Multiple sclerosis (MS) is a debilitating neurodegenerative disease that consists of muscle rigidity (spasticity), cramps, chronic pain, tingling and prickling in extremities, ataxia, tremors and vesical and intestinal dysfunctions (Amar, 2006). The following is a summary of findings across 17 controlled clinical studies:
- Orally administered THC objectively improved mobility and spasticity, and subjectively improved muscle spasms, pain, sleep quality and general health in patients with MS. Results also showed a decrease in hospitalisations for relapses. Similar results were also observed when MS patients used THC/CBD mixtures (Amar, 2006).
- MS patients who perceived symptom relief when using Sativex, maintained that relief for 434 days. Sativex was also found to be significantly more effective at relieving spasticity (Hazekamp & Grotenhermen, 2010).
- Cannador and THC had a significant effect in urge incontinence episodes amongst MS patients (Hazekamp & Grotenhermen, 2010).
- Sativex, Cannador and a THC/CBD oromucosal spray significantly decreased spasticity in patients. Patients also reported reduced sleep disturbances and depression, and an overall impression of change while taking Sativex (Kowal, et al., 2016).
- Inhaled Cannabis was found to reduce symptoms of spasticity and pain in MS patients that were resistant to other treatments (Kowal, et al., 2016).
- Spinal cord injuries exhibit similar symptoms to MS. Studies showed similar results to the MS studies (Amar, 2006).
- Huntington’s disease is also a neurodegenerative disease like MS and a study found that Nabilone reduced involuntary movements that are associated with the disease (Legare, et al., 2022).
Treatment of Gilles de la Tourette’s Syndrome
Gilles de la Tourette’s syndrome is a neuropsychiatric disorder that consists of verbal and physical tics, and other behavioural and cognitive disorders. 2 studies found that oral THC reduced tics, and did not impair neuropsychological performances (Amar, 2006) (Legare, et al., 2022).
Treatment of Epilepsy
Epilepsy affects approximately 1% of the world’s population. 1 study of 15 patients, showed that oral CBD either stopped or improved convulsions (Amar, 2006). Another 2 studies shared similar oral CBD findings in treatment-resistant epilepsy patients (Legare, et al., 2022).
CBD may also have potential in managing seizures caused by Dravet syndrome and tuberous sclerosis (Legare, et al., 2022).
Treatment of Glaucoma
Glaucoma is caused by an increase in intraocular pressure and can lead to blindness (Amar, 2006). The following is a summary of the findings from over 3 controlled clinical studies:
- Smoked Cannabis and THC eye-drops reduced intraocular pressure (IOP) in patients with glaucoma (Amar, 2006).
- Oromucosal spray that consists of THC significantly reduces IOP, while oromucosal spray that consists of CBD does not reduce IOP ion glaucoma patients (Hazekamp & Grotenhermen, 2010).
- Sublingual and intravenous preparations of THC have also been shown to reduce IOP in glaucoma patients (Legare, et al., 2022).
Treatment of Parkinson’s Disease
Parkinson’s disease affects the nervous system and parts of the body controlled by the nerves, and has symptoms such as tremors, stiffness or slowed movement (Mayo Clinic Staff, 2024).
One study showed that nabilone significantly reduced total levodopa-induced dyskinesia when compared to placebo, but exhibited no antiparkinsonian action (Amar, 2006) (Legare, et al., 2022).
Another study found that oral CBD has the potential to enhance the quality of life of Parkinson’s disease patients without psychiatric comorbities. It is worth noting that this study also found that the CBD did not show any neuroprotective or motor effects (Kowal, et al., 2016).
Treatment of Intestinal Dysfunction
There have been 3 studies completed to date on the use of Cannabis to treat intestinal dysfunction. The following is a summary of the findings from these clinical studies:
- THC was found to significantly slow gastric emptying in females and a significantly delay gastric emptying in males. THC was also seen to increase fasting gastric volumes in males (Hazekamp & Grotenhermen, 2010).
- THC was found to potentially have application in treating diarrheal diseases such as irritable bowel syndrome (IBS) (Hazekamp & Grotenhermen, 2010).
- Oral THC improved colonic compliance and decreased fasting colonic motility in patients with IBS (Kowal, et al., 2016).
Treatment of Schizophrenia
A 4-week study was conducted across 42 patients on the antipsychotic properties of CBD in acute schizophrenia. The study found a significant decrease in psychotic symptoms after 2 and 4 weeks (Hazekamp & Grotenhermen, 2010).
A study found that oral CBD displayed significant improvements in clinical psychosis symptoms of patients suffering from schizophrenia (Kowal, et al., 2016).
Treatment of Crohn’s Disease
Crohn’s disease is a chronic inflammatory bowel disease that affects your digestive tract (MedlinePlus, 2023). A single study has been completed to date on the impact of inhaled Cannabis on the disease. The results found that inhaled Cannabis had a high decrease in Crohn’s Disease Activity Index (CDAI) scores, meaning Cannabis may result in remission in treatment-resistant patients over time (Kowal, et al., 2016).
Treatment of Cannabis Dependence
A study tested if Sativex had an efficacy in treating Cannabis dependence and withdrawal. The results of the study showed that Sativex decreased the severity of Cannabis withdrawal, withdrawal-related irritability, depression and Cannabis cravings when compared with placebo (Kowal, et al., 2016).
Another study used oral THC to treat Cannabis dependence and withdrawal. The study found that oral THC is promising for the treatment of Cannabis dependence and can decrease withdrawal symptoms (Kowal, et al., 2016).
Treatment of Anxiety
2 studies were conducted to see if oral CBD had any effects on generalised social anxiety disorder (SA). Patients in both studies subjectively reported reduced anxiety levels and results from tests completed during the study further confirmed these self-reports (Kowal, et al., 2016).
A study that was conducted on active-duty military personnel with post-traumatic stress disorder (PTSD) showed a Nabilone had a significant and beneficial effect in reducing the frequency of PTSD-related nightmares (Legare, et al., 2022).
Treatment of Amyotrophic Lateral Sclerosis
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease of upper and lower motor neurons. One study found that Nabiximols improve spasticity in ALS patients. Although there are limited studies on Cannabis for ALS, a survey found that patients prefer Cannabis medication over prescription medication due to their subjective perceptions of improvement in symptoms (Legare, et al., 2022).
Treatment of Opioid Use Disorder
A study found that daily Cannabis use was associated with lower opioid use during opioid use disorder (OUD) treatment. Another study found that Cannabis users exhibited less withdrawal symptoms. In lieu of additional studies, the belief is that Cannabis, more specifically CBD, may be of added value when using traditional OUD medication-assisted treatments (Legare, et al., 2022).
Other
The following is a list of potential therapeutic actions and indications of Cannabis or its constituents. Note that clinical trials have not been completed or are currently being completed on the items below:
- Anti-inflammatory effects (Amar, 2006).
- Anticancer effects (Amar, 2006) (Hazekamp & Grotenhermen, 2010) (Legare, et al., 2022).
- Treatment of psychotropic drug dependence (Amar, 2006).
- Treatment of rheumatoid arthritis (Amar, 2006).
- Treatment of Hepatitis C (Hazekamp & Grotenhermen, 2010).
- Treatment of sleep disorders (Legare, et al., 2022).
- Chronic obstructive pulmonary disease (COPD) (Kowal, et al., 2016).
Disclaimer
The information presented in this post is intended as an informational guide. The remedies, approaches and techniques described herein are meant to supplement, and not to substitute for, professional medical care or treatment. They should not be used to treat a serious ailment without prior consultation with a qualified health care professional.
References
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