What is medical cannabis?
Cannabis is one of the oldest medicines that has been used for over 5,000 years in many parts of the world. In recent years, there has been more interest and research into this fascinating plant. It has been shown to help in a wide variety of different conditions, including chronic non-cancer pain, inflammatory bowel disease, endometriosis, fibromyalgia, anxiety and depression, PTSD and insomnia. (National Academies of Sciences, Engineering, and Medicine 2017)
The cannabis plant has over 750 chemicals which can be grouped as cannabinoids, terpenes and flavonoids. There are approximately 140 cannabinoids, of which cannabidiol (CBD) and tetrahydrocannabinol (THC) are the most well known and researched. However, the terpenes and flavonoids have beneficial actions and work synergistically with the cannabinoids – known as the entourage effect.
CBD is the non-psychoactive component, and THC produces the psychoactive effects (“high”) that cannabis is well known for. Each has its unique properties, but both are anti-inflammatory. When THC is combined with CBD, it has been found that this helps reduce THC’s psychoactive side effects.
CBD is not currently a first-line medication– as per the RACGP (Royal Australian College of General Practitioners) guidelines, “medicinal cannabis products should only be considered when all first line, conventional, evidence-based treatment options have been exhausted and after detailed discussions of the potential benefits and harms of medicinal cannabis with the patient”. If ineffective or if they cause side effects, then medical cannabis can be considered.
Cannabinoids can be classified into three categories-
- Endocannabinoids- naturally produced in the body
- Phytocannabinoids – from plants
- Synthetic cannabinoids- pharmaceutical products
What is the endocannabinoid system (ECS)?
We have an endocannabinoid system (ECS) – these natural cannabinoids interact with receptors all over the body, and the ECS modulates different body systems to help achieve homeostasis. It is involved in many functions, including inflammation, pain, sleep, appetite, digestion, metabolism, cardiovascular function, bone development, reproduction, immune function and memory.
The ECS was discovered in 1992. They discovered the body’s two natural endocannabinoids– anandamide (AEA) (from the Sanskrit word, “ananda” meaning bliss; similar structure to THC) and 2- AG (similar structure to CBD) and also discovered that there were two types of cannabinoid receptors – CB1 and CB2. AEA is a natural agonist of CB1 and 2-AG is a natural agonist of CB2.
Most of the receptors are CB1 receptors and located mainly in the central nervous system (CNS) which includes the brain (cognitive functions, memory) – eg hypothalamus, amygdala, hippocampus, basal ganglia, cerebellum, cerebral cortex. CB2 receptors are in the immune system and gut (immune function, pain and inflammation). Both types of receptors can be found in the liver, pancreas and bone marrow.
CBD and THC
CBD – this is the non-psychoactive component that has many beneficial properties including:
- anti-inflammatory
- anti-epileptic
- anxiolytic
- analgesic
- anti-emetic
- anti-psychotic
It’s thought to inhibit the enzyme that breaks down anandamide (one of the two natural cannabinioids in the body) and and stimulates the production of 2-AG (the second naturally occurring cannabinoid).
THC – produces the psychoactive effects (“high”) that cannabis is known for. However, it also has many other benefits including:
- analgesic
- anti-spasmodic
- improving appetite
- anti-inflammatory
- anti-emetic
- and spasticity
THC binds to both CB1and CB2 receptors in the brain whereas CBD binds very weakly to CB1, having more of an effect on ion channels, receptors and enzymes. It has been found that when THC is combined with CBD, this helps to reduce the THC’s psychoactive side effects.
CBD and THC can be used alone on in specific combinations to help a wide variety of conditions.
What conditions is cannabis useful for?
- Chronic non cancer pain (CNCP)
- Chemotherapy induced nausea and vomiting (CINV)
- Cancer pain
- Epilepsy
- Multiple Sclerosis
- Inflammatory bowel disease
- Autism
- Endometriosis
- Fibromyalgia
- Anxiety/Depression
- PTSD
- Parkinsons disease
- Alzheimers disease
- Sleep disturbance associated with Obstructive sleep apnoea (OSA)
