Medical Cannabis has been legal in the UK since 2018, and although NHS prescriptions are still uncommon, private access has grown quickly. There are now over 30 private clinics who can prescribe cannabis-based products for medicinal use (CBPM), resulting in more than 50,000 prescriptions being issued last year alone. Factor in unregulated online products, and the true number of users is far higher. This means that as a manager, you’re increasingly likely to encounter employees using these medications — and you need to know how to respond confidently and safely.
Managers don’t need to be pharmacology experts, but understanding the basics helps you make informed decisions. There are 3 types of cannabis:
- CBD products – Widely available on the high street. They contain only trace THC and are unlikely to impair performance.
- CBPM (Cannabis-Based Products for Medicinal Use) – These do contain THC and should only be prescribed by a specialist doctor.
- THC – This is the psychoactive component responsible for the “high” in recreational cannabis. It’s a Class B controlled drug.
As a manager, it is important to recognise the impact that cannabis use can have on your workforce. THC can impair an employee’s ability to concentrate and make decisions, slow their reaction time, and affect their coordination. It may also impair their short-term memory, alertness, and stability.
Some individuals may also experience nausea, rapid heart rate, or in rare cases, hallucinations, or psychosis. For safety-critical roles, these effects can create significant risk.
Drug tests screen for THC, so as legally sold CBD products contain only trace amounts, they’re unlikely to cause issues. However, online CBD products and all medical cannabis products may contain higher THC levels, meaning a non-negative result is possible.
If an employee discloses that they are taking Medical Cannabis, your next step is straightforward: refer them to your Occupational Health Provider as soon as possible.
Managers should avoid handling medical details directly. The GDPR-compliant route is to let Occupational Health confirm the legitimacy of the prescription and the underlying condition.
Occupational Health will assess the employee’s fitness to work and evaluate any safety implications. They will also be able to advise you on reasonable adjustments that may be required to their working conditions, which will be done in liaison with the prescribing doctor, where appropriate.
This protects both the employee and the organisation.
As current drug tests cannot distinguish between prescribed and illicit cannabis, it is important that all non-negative results undergo a formal review by a Medical Review Officer (MRO).
The Medical Review Officer, who is a doctor trained in drug and alcohol testing, will examine the lab findings, and consider any declared medications, including CBPM, before determining whether the THC level is consistent with legitimate medical use.
The Medical Review Officer’s Report may also highlight any potential safety concerns.
This independent review helps to ensure fairness and clinical oversight.
It’s important to remember that the MRO only interprets the test result. Occupational Health still need to decide whether the employee is fit for work. You may also need to complete a role-specific risk assessment before allowing anyone in a safety-critical position to return to their duties.