Should cannabis be legalised for pain relief?

As a controversial report calls for the legalisation of the drug for medical use, we examine the evidence

It’s approved as a painkiller all over the world

support their broader campaign on recreational usage and I do not support general legalisation.’

To avoid confusion, he has told us he ‘will resign from CLEAR’. His report, he added, is ‘balanced and the science is unarguable… I set the evidence threshold very high so that no one can sensibly refute the conclusions’.

Nevertheless, his connection with CLEAR will do nothing to ease concerns that legalising cannabis for medical use could lead to decriminalising it for recreational use. Of the 11 peers and four MPs who took part in the APPG hearings that led to the report only one — Lord Norton — is Conservative.

The National Drug Prevention Alliance, which opposes relaxing UK drug laws, dismissed the APPG report as ‘without merit’.

David Raynes, a former assistant chief investigations officer with HM Customs and political affairs director of the alliance, said it was ‘pushed almost entirely by a few parliamentarians and users who have failed to get legalisation for recreational use any other way’.

Professor Barnes told Good Health that ‘many will be surprised about the strength of evidence for the use of cannabis’, which was ‘overwhelming for use in chronic pain’. But expert organisations contacted by Good Health expressed surprise about the report itself.

‘It is interesting that the authors feel there is sufficient evidence to justify recommendation of use of cannabis formulations for pain,’ says Roger Knaggs, a spokesman for the British Pain Society.

‘Most pain clinicians would say there is insufficient evidence to recommend and balance with the risks of misuse.’

Professor Knaggs, an associate professor in clinical pharmacy practice at the University of Nottingham, said there were ‘significant sideeffects and potential harms in the use of cannabis that appear to have been overlooked’.

The Barnes report is also in stark contrast to the findings of a study published in the journal Addiction in 2014, which found regular cannabis users ‘double their risks of experiencing psychotic symptoms and disorders’.

Professor Wayne Hall, of the National Addiction Centre at King’s College London, reviewed all the scientific evidence on the effects of cannabis use published between 1993 and 2013 and concluded there had been ‘consistent associations found between regular (especially daily) cannabis use and adverse health and psychosocial outcomes’. He also found that one in ten of all regular cannabis users became dependent on the drug, rising to one in six among those who started using it in adolescence.

The Royal College of Psychiatrists said it is ‘in favour of more research to explore the use of cannabis products as medicines’. Professor Colin Drummond, chair of the college’s addictions faculty, told Good Health it was ‘important to note that cannabis carries significant mental health risks for some individuals. Its use increases the risk of developing psychosis, depression and anxiety’.

The question must be: why not develop prescription medicines based on cannabis? In fact, there are already two on the market.

Nabilone, a synthetic cannabis-type drug marketed in the UK as Cesamet, was licensed in 1982 as a hospital-only treatment for nausea and vomiting caused by chemotherapy where conventional medication hadn’t worked.

In 2010 Sativex, developed by a UK company, became the first medicine based on cannabis for use in the UK. GW Pharmaceuticals has been licensed by the Home Office since 1998 to grow its own cannabis plants, which it does in ‘highly secure computercontrolled glasshouses’.

The peppermint-flavoured mouth spray can be prescribed only for the treatment for spasticity, a loss of muscle control experienced by MS patients. However, it is expensive — a 10ml vial, which lasts 22 days, costs £125 — and is rarely prescribed.

‘We are keen that Sativex is made routinely available on the NHS throughout the UK for its licensed indication,’ the MS Society told Good Health.

Because of the strict terms of their licences, neither Sativex nor Nabilone can be prescribed for a different purpose. To widen their licences would involve new trials and regulatory approval, which would be extremely costly.

Nevertheless, GW Pharmaceuticals has trials under way in the U.S. and Europe with the aim of having Sativex approved for the treatment

of the ‘chronic, unremitting pain in deep tissues that results from cancer’.

The existence of these drugs demonstrates that the Government accepts cannabis has medicinal value, says the APPG.

This, says its report, ‘seems irrational and contrary to the Government’s scheduling decision’ over cannabis which, if legalised for medical use, would bring the benefits of the drug to hundreds of thousands of people at a fraction of the cost to the NHS’.

The report recommends that cannabis be grown by licensed producers in the UK and made available on NHS prescription for specified conditions.

In the Netherlands, the Office of Medicinal Cannabis — part of the ministry of health — oversees the production of cannabis for medicinal and scientific purposes by licensed growers, and has a monopoly on supplying medicinal cannabis to pharmacies. It also exports cannabis for medicinal use to Italy, Germany, Finland, Canada and the Czech Republic.

Bedrocan, the company that has supplied the Dutch ministry since 2003, produces six medicinal ‘blends’ of cannabis, each with a different proportion of the chemicals most important medically — tetrahydrocannabinol (THC) and cannabidiol (CBD).

These stimulate ‘receptor’ cells throughout the nervous system controlling appetite, pain and mood. The correct proportion of chemicals is critical. With illegal cannabis there is no way of knowing just what it contains and this, says the APPG, is another good reason for the production and prescription of medical-grade cannabis to be legalised and regulated.

Yet many will remain deeply concerned about the possibility of addiction and not least the very real dangers of THC, the chemical in cannabis that has been linked to psychosis and schizophrenia. Though Professor Barnes suggests the risk of cannabis causing these is ‘very low’, there is ‘probably a link in those who start using cannabis at an early age and also if the individual has a genetic predisposition to psychosis . . . we recommend caution with regard to the prescription of cannabis for such individuals’.

It is far from clear how these at-risk individuals would be identified.

But for Frances Lotter and the many others tackling short-term terminal illness, these are moot points. As a result of the year she spent in and out of hospital with Jordan, she says: ‘I now know a lot of mothers with children with cancer for whom it’s an essential part of their treatment plan.

‘They are having to pay extortionate prices — people know you are vulnerable that you’ll do anything to help your child or your partner and they’re exploiting that.

‘If it was managed properly and legalised that wouldn’t happen.’