A drug addiction treatment centre claims to be helping patients give up heroin and cocaine with medical marijuana.

Cannabis is more frequently associated with getting high than getting sober – but the directors of one rehab facility in Los Angeles say it can reduce overall harm caused by drug use.

“Some say it's hypocritical because, you know, you're supposed to go to rehab to get off drugs,” Joe Schrank, founder of the High Sobriety clinic, told CNN.

But marijuana “can really help people with pain management and other health issues, or it can help them be safer“, he said.

Mr Schrank said a “cannabis detox” can be helpful for those with severe addictions because unlike with harder drugs, there is no known lethal dose.

The centre has so far treated around 50 people with the drug. Mr Shrank said it can help alleviate the distressing symptoms of going ‘cold-turkey’ and reduce drug dependence in the long term.

However, the effectiveness of medical marijuana has not been scientifically proven and other rehab experts have warned against the use of one recreational drug to treat the abuse of another.

The controversial idea is a type of strategy known as harm reduction – policies and therapies that aim to reduce the harm people do to themselves or others due to drug use, as opposed to the all-or-nothing approach traditionally taken towards addiction.

Oxford University has launched a £10m research programme into the medical use of marijuana, which one of the university’s associate professors described as an “area of huge untapped potential”.

Cannabis is a Class B drug in the UK, but the cannabidiol CBD, which does not create the ‘high’ associated with recreational use, has been reclassified as a medicine by the Medicines & Healthcare products Regulatory Agency (MHRA).

This means doctors can, in exceptional cases, prescribe medicines containing CBD to be manufactured or imported for a patient’s use.