What is Medicinal Cannabis?

Dr Lisa Beckett

May 2022

Medicinal cannabis products use the cannabis plant to treat physical and psychological conditions. Cannabis contains chemicals called cannabinoids. Cannabinoids act on receptors in the Endocannabinoid System (ECS) to produce effects in the body. The main cannabinoids in medicinal cannabis are Δ 9-tetrahydrocannabinol (THC) and cannabidiol (CBD).

Medicinal cannabis contains known quantities of THC and CBD, complies with pharmaceutical manufacturing standards and is produced with the intention of treating medical conditions or symptoms. The composition of the street cannabis product is unknown and may contain harmful substances including fungi, bacteria and heavy metals.

Cannabis has been used medicinally for centuries, dating back to ancient China. It was introduced to the Western world in the early 1800s by medical pioneers such as William O’Shaughnessy, who used it to treat various conditions including pain, inflammation, and seizures. In the mid-1900s, cannabis was used extensively to treat a variety of conditions, including nausea and vomiting associated with cancer chemotherapy. By the 1970s, the therapeutic benefits of cannabis were largely forgotten due to its criminalisation. In recent years, however, there has been a resurgence in interest in its potential medical applications, particularly for treating chronic pain, anxiety, and seizures.

The therapeutic effects of cannabis are thought to be mediated by the body’s Endocannabinoid System, which is a network of receptors located throughout the body that are activated by cannabinoids. The ECS is involved in a variety of physiological processes, including pain modulation, immune function, and appetite.

What are cannabinoids?

Cannabis is a complex plant, containing hundreds of different chemicals known as cannabinoids. THC is the cannabinoid that is responsible for the plant’s psychoactive effects, while CBD is thought to have a number of therapeutic benefits, including anti-inflammatory and analgesic (pain-relieving) properties.

THC

Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis. It is one of many cannabinoids in the plant, but it is the only one that produces a psychoactive effect.

THC binds to cannabinoid receptors in the brain and produces a range of effects, from relaxation and increased appetite to paranoia and anxiety. THC also produces the "high" people feel when they smoke marijuana or eat foods containing it.

CBD

CBD does not produce a high. Some people prefer CBD because it does not have this effect. CBD, also known as cannabidiol, is a compound found in hemp and marijuana plants. Unlike THC, the compound that gets users high, CBD is non-psychoactive.

CBD is thought to have a variety of potential health benefits, including reducing anxiety, relieving pain, and improving sleep. CBD is available in a variety of forms, including oils, capsules, and edibles.

What is medicinal cannabis used for?

In Australia, the TGA has approved use of medicinal cannabis for a number of conditions including (but not limited to):

  • nausea and vomiting due to chemotherapy
  • epilepsy in children
  • palliative care
  • cancer pain
  • neuropathic pain
  • spasticity from neurological conditions (such as multiple sclerosis)
  • anorexia and wasting associated with chronic illness (such as cancer)
  • mental health conditions (such as anxiety, depression and PTSD)

Despite a growing body of evidence for use, there are a number of challenges that need to be addressed before cannabis can be widely accepted as a mainstream treatment. These include the lack of large-scale, high-quality clinical trials, the potential for abuse and dependence, and the lack of standardization in terms of product quality and potency. Nonetheless, the medical potential of cannabis is considerable, and further research is likely to uncover even more therapeutic benefits.

What are the side effects?

All medications have the potential to cause unwanted side effects and medicinal cannabis is no exception. Side effects may depend on the type, dose and form of cannabis being used.

The known side effects from medicinal cannabis treatment include, but are not limited to;

  • fatigue and sedation
  • dizziness
  • confusion
  • nausea and vomiting
  • fever
  • decreased or increased appetite
  • dry mouth
  • diarrhoea

Products high in THC have been associated with:

  • feeling ‘high’ or feeling dissatisfied
  • depression
  • confusion
  • hallucinations
  • paranoid delusions
  • psychosis
  • cognitive distortion (having thoughts that are not true)

Medicinal cannabis side effects are commonly dose-dependent, so it’s important to follow the dosing recommendations and use only under medical guidance as it may interact with other medicines or supplements.

References