The therapeutic use of marijuana to treat a range of conditions has been gaining widespread support in Europe and the US for a number of years. In Australia there is a growing move toward the legalisation and use of medical cannabis. Victoria was the first state (1), followed by NSW and most recently Queensland (2). The impact of legalising a potentially impairing drug is causing concern in many workplaces across the country.
Current scientific evidence is pointing to its use in epilepsy, MS, treating the side effects of chemotherapy and managing severe chronic pain. However it shouldn’t be thought that all the patients are getting high on smoking joints. There have been identified over 100 different cannabinoids derived from the marijuana plant. The most common is delta-9-tetrahydrocannabidol (THC) which is the primary psychoactive compound in marijuana. However the compounds that are being primarily investigated for medical use such as cannabidiol(CBD), Cannabigerol (CBG) and tetrahydrocannabivarin (THCV) have virtually no psychoactive or impairing effects (3). In addition the marijuana plants that are being grown to produce these compounds have been genetically modified to produce less than 3% of the THC component.
Therefore at this stage the likely impact on the workplace is going to be low, the medicinal cannabinoids are not impairing and not detectable in onsite testing devices. However in the future there may be more widespread medical applications utilising the impairing THC component. In that case workplaces need to apply the same principles of any potentially impairing medication, production of prescriptions, fitness for duty assessments and testing to ensure that the medication is being taken at the recommended therapeutic level.