Unfortunately it seems lots of people are a bit out of date on this.
Medical marijuana has been available for private prescription in the UK for three years now. The UK is the worlds biggest producer and exporter of medical cannabis products (even more than countries like Canada where it's legal!)
I myself have been prescribed medical marijuana for fibromyalgia after suffering two rare lung diseases and the floodgates are now open with thousands of people paying slightly more for privately prescribed marijuana for the security and legal protection it gives them.
"At the end of 2019, there were less than 250 active medical cannabis users in the country; by 2024, this figure is expected to be over 337 thousand."
Here are just 15 clinics in the UK offering prescription cannabis products for various private healthcare fees: https://www.ukmccs.org/members-area/directories/clinic-directory/
These clinics are supplied by a number of diffferent legal cannabis pharmacies.
I was recently tasked with drafting a drug and alcohol testing policy for a client and I was very interested in how this grey area could be dealt with, when I updated the client on my findings they decided they would park the drug and alcohol testing for now!
It is a minefield and more guidance and legislation, needs to be put in place because the normalisation of medicinal use and likely soon recreational use will change what can be enforced significantly.
How can you judge when someone is 'under the influence of a narcotic' and when someone is getting needed pain relief from a prescribed medicine?
Drug tests can detect tetrahydrocannabinol (THC), in urine, blood, and hair for many days/weeks after use, while saliva tests can only detect THC for a few hours. This is because of the way the body metabolizes THC.
THC is a lipid-soluble chemical. This means that it binds to fat in the body, which increases the length of time it takes for someone to eliminate THC completely.
Urine testing identifies cannabinoids in the fats in urine but only shows someone has used it not that they are under the inflence of it whilst at work.
I don't have the answers but I'm interested in how it can be controlled, monitored, tested and how grey areas of the rights of workers and the risk of intoxicated persons in the workplace affects theirs and others safety and how we as health and safety professionals can adapt to ensure the HEALTH and safety of our site users.