Cannabis

For this week's episode on Movers and Shakers, we're putting down our pints and rolling a joint, talking about how cannabis could be an important part of Parkinson's treatment. Subject to stigma over its use, have we been ignoring the therapeutic qualities of the plant? To discuss this, we talk to Professor Mike Barnes, a world expert in medical cannabis, and hear from many of our listeners who have dabbled with the various strains. With uses for everything from pain to sleep, this is an in-depth look at a much-maligned treatment option.

Each week, Rory Cellan-Jones guides us between the laughs and moans in the pub. To read Rory's summary of this week's episode, click here.

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Guest Biographies

Mike Barnes

[Photo: profmichaelbarnes.co.uk]

A Consultant Neurologist and medical cannabis expert, for over 20 years, Professor Mike Barnes has been at the forefront of medical cannabis in the UK. He is the chair and founder of the Cannabis Industry Council which has over 100 members representing the entire UK cannabis industry from the supply chain to research bodies and provides a collective voice for the entire UK cannabis industry..

From his work helping to bring Sativex to market in the early 2000s  to his ground-breaking report on the evidence for medical cannabis for the All-Party Parliamentary Group on Drug Policy Reform in 2016, Professor Barnes is the UK's leading medical cannabis expert.

[Taken from Professor Mike Barnes' website]

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Following publication of this episode, we received a message from Dr James Woods, adding a further perspective on the use of cannabis therapies in Parkinson's.

Dear Movers and Shakers,

I am an NHS consultant physician and geriatrician with a specialist interest in Parkinson’s disease, I care for around 300 people with Parkinson’s within my clinic, mostly over the age of 65.

I listen to the Movers and Shakers to expand my understanding of issues affecting people living with Parkinson’s and often to give me a heads up to questions that might arise in clinic! I admire your passion, honesty and good humour and believe you have become a trusted resource for many.

It was with some dismay, therefore, that I listened to the episode on Cannabis in Parkinson’s with Professor Mike Barnes. I recognise this was an important topic, and is something patients do ask about, however I do not believe you provided a reasonable level of balance to allow your listeners to come to informed understanding of the issues.

Margaret McCartney, a GP and director of the Centre for Evidence and Values in Healthcare at St Andrews University, recently wrote on ‘X’ that: ‘if tempted to take healthcare advice from a person who is also selling you the thing they are advising you to do: maybe think 1) do I have independent evidence on this? 2) who is regulating the person selling me this? and 3) is the media explaining the conflict of interest?’

You introduce Professor Barnes as ‘a consultant neurologist and medical cannabis expert.’ I think it is important to understand that Professor Barnes no longer holds a registration with the General Medical Council (GMC), the UK medical regulator, and is therefore no longer a practising doctor (he does declare this himself on his website profmichaelbarnes.co.uk). You also did not mention that he has strong ties to the medicinal cannabis industry, for example he is president of the Cannabis Industry Council. This isn’t to say that Prof Barnes is not an expert in this area. But, as Dr McCartney highlights, it is important to understand all possible biases when presented with information.

This was especially irksome in a podcast where Prof Barnes seemed to dismiss the concerns of NHS clinicians to the use of medicinal cannabis, citing bias and lack of knowledge when doing so.

I would caution against using numbers of private prescriptions as evidence of effectiveness of a medicine, this is fraught with many confounders not least the possibility for a strong placebo effect, which some studies have suggested.

Major Parkinson’s organisations currently stop well short of supporting the use of these products, despite having no rationale to do so if they believed there to be benefit. For example:

Parkinson’s UK’s policy statement says: ‘there is little conclusive clinical evidence of the benefits of cannabis-based medicinal products on Parkinson's symptoms. We believe the government should prioritise funding clinical trials into cannabis-based medicinal products and encourage participation from people with Parkinson's.’

The Parkinson’s Foundation has said: ‘Given the lack of any clear data supporting the use of cannabis in PD, the Foundation does not endorse their use for PD symptoms or to modify disease progression.’

I, like the majority of NHS clinicians who care for people with Parkinson’s, would welcome any treatments that relieve symptoms of the disease and I do not believe there is any ‘ideological’ objection to the use of medicinal cannabis as long as it is appropriately evidenced and regulated and I believe there is work yet to achieve this.

Dr James Woods MBChB, MRCP(UK)(Geriatric Med), FRCP(Edin)