Cannabis

Debate between Dan Poulter and Paul Flynn

Monday 12th October 2015 Westminster Hall

[Dr Daniel Poulter (Central Suffolk and North Ipswich) (Con)]

It is a pleasure to serve under your chairmanship, Mr Evans. I commend the hon. Member for Newport West (Paul Flynn) on bringing the debate to the House and on this grown-up, sensible discussion about a topic that is often taboo and should not be because it affects the lives of many of our constituents.

A number of issues have been covered, including the criminal justice system, which I will come back to. I will pick up on a couple of points made articulately by the hon. Member for Caithness, Sutherland and Easter Ross (Dr Monaghan) on the medicinal uses of cannabis. There are some issues with the current law that need to be looked at, which perhaps make the medicinal use and the research of medicinal use more challenging. I also want to touch on some medical evidence. My right hon. Friend the Member for Hitchin and Harpenden (Mr Lilley) made some compelling points during his eloquent speech for the legalisation of cannabis. I am not, unfortunately, able to support him and I hope that my discussion of some of the medical background will help to explain why.

I have picked many of my remarks from a balanced review by the Royal College of Psychiatrists, which I hope we all consider to be well-resourced and an appropriate source of material for balancing the medical evidence on the use of cannabis as it looks at not only mental health, but physical health. Most of my remarks will be based on the evidence that it has collated. The college does not have a view on the legal position but, none the less, it wants people to look at the evidence and make up their minds. I will give my view, having reviewed some of that evidence.

Although there has been a steady reduction in the use of cannabis since 1996, about 2.3 million of those aged 16 to 59 have reported using cannabis in the past year. Frequent use of cannabis is more than twice as likely among young people. In spite of many Government and media warnings about health risks, many people see cannabis as a harmless substance that helps people to relax and chill—a drug that, unlike alcohol and cigarettes, might even be good for their physical and mental health. I will come to the point that that is clearly not the case.

It is worth quoting directly from the Royal College of Psychiatrists about how cannabis and cannabis plants have evolved over the past few years. My right hon. Friend the Member for Hitchin and Harpenden said that drug use is very different from when he was at university. That may well be the case, but the evolution of cannabis and the increasing frequency of high-potency cannabis—skunk, as a number of types of stronger cannabis in general are often referred to—has changed some of the health risks associated with cannabis use. As the Royal College of Psychiatrists says,

“Over the last 15 years, skunk has invaded the street market and its THC content is about 2-3 times higher than the ‘traditional’ cannabis used in earlier years.”

I will come to THC content and the different chemical components of cannabis, but the royal college continues:

“In the UK, most sold materials is home grown because of a loop hole in the law making it legal to buy seeds over the internet.”

I have some sympathy with the points raised by my right hon. Friend the Member for Hitchin and Harpenden: there are some challenges in the law and, de facto, we effectively have decriminalisation of cannabis in many areas of the country. I would be interested to hear the Minister’s views on that. Does he see a clear distinction between legalising a drug that we know to be harmful and a more decriminalising approach with police discretion, as we have at the moment? I believe the approach we have at the moment is probably the right one, given some of the harmful effects that I will speak about.

[Paul Flynn]

Will not the hon. Gentleman respond to what was said by his right hon. Friend the Member for Hitchin and Harpenden (Mr Lilley): skunk—that expression is only used in this country because there are different strengths of THC—is a product of prohibition just as distilled spirit, the main killer drug, was in America? Does he agree that if we end prohibition and have a legal market, people will get to use the cannabis of their choice—not necessarily the one that the illegal market wants them to take?

[Dr Poulter]

I do not necessarily accept the view that stronger or different forms of cannabis are developed as a result of prohibition. Take Holland as an example: different varieties of cannabis are available in various cannabis coffee shops in Amsterdam. People there have an opportunity to decide which potency and strength they use. I do not necessarily accept that prohibition has driven a market towards creating stronger varieties of cannabis. We know that stronger types of cannabis, such as skunk, have a stronger correlation with psychosis and some of the harmful mental health effects that are linked with the use of cannabis and the chemicals it contains.

On that subject, there are about 400 chemicals in an average cannabis plant. The four main compounds are delta-9-tetrahydrocannabinol, cannabidiol, delta-8-tetrahydrocannabinol and cannabinol. Apart from CBD—cannabidiol—these compounds are psychoactive, the strongest being delta-9-tetrahydrocannabinol. The stronger varieties of the plant contain little CBD, while the delta-9-tetrahydrocannabinol content is a lot higher. We are talking about a number of psychoactive substances. The stronger plants and varieties tend to contain larger amounts of the more psychoactive components and compounds.

When cannabis is smoked, its compounds rapidly enter the bloodstream and are transported directly to the brain and other parts of the body. The feeling of being stoned or high—like my right hon. Friend the Member for Hitchin and Harpenden, I have not had the experience—is caused mainly by the delta-9-tetra- hydrocannabinol binding to a cannabinoid receptor in the brain. Most of these receptors are found in the parts of the brain that influence emotion, pleasure, memory, thought, concentration, and sensory and time perception. Cannabis compounds can also affect the eyes, ears, skin and stomach.

There are a number of effects, some of which people describe as pleasurable and some of which we know are harmful. I want to touch on the mental health problems associated with cannabis use in some detail. The Royal College of Psychiatrists has published information on the subject:

“There is growing evidence that people with serious mental illness, including depression and psychosis, are more likely to use cannabis or have used it for long periods of time in the past. Regular use of the drug has appeared to double the risk of developing a psychotic episode or long-term schizophrenia. However, does cannabis cause depression and schizophrenia”—

there is a legitimate discussion about reverse causality—

“or do people with these disorders use it as a medication?

Over the past few years, research has strongly suggested that there is a clear link between early cannabis use and later mental health problems in those with a genetic vulnerability”—

my right hon. Friend made that point—

“and that there is a particular issue with the use of cannabis by adolescents.”

On depression, the Royal College of Psychiatrists says:

“A study following 1,600 Australian school-children, aged 14 to 15 for seven years, found that while children who use cannabis regularly have a significantly higher risk of depression, the opposite was not the case—children who already suffered from depression were not more likely than anyone else to use cannabis. However, adolescents who used cannabis daily were five times more likely to develop depression and anxiety in later life.”

That covers the issue of reverse causality.

I particularly want to talk about psychosis, schizophrenia and bipolar disorder. The Royal College of Psychiatrists states:

“There is now sufficient evidence to show that those who use cannabis particularly at a younger age, such as around the age of 15, have a higher than average risk of developing a psychotic illness, such as schizophrenia or bipolar disorder.

These studies also show that the risk is dose-related. In other words, the more cannabis someone used, the more likely they were to develop a psychotic illness… a study in Australia recently showed that those who used cannabis could develop the illness about 2.70 years earlier than those who did not.

Why should teenagers be particularly vulnerable to the use of cannabis? It is thought that this has something to do with brain development. The brain is still developing in the teenage years—up to the age of around 20, in fact. A massive process of ‘neural pruning’ is going on. This is rather like streamlining a tangled jumble of circuits so they can work more effectively. Any experience, or substance, that affects this process has the potential to produce long-term psychological effects.

It is also known that not everyone who uses cannabis, even at a young age, develops a psychotic illness.”

My right hon. Friend articulately raised that point. The Royal College of Psychiatrists continues:

“The available research shows that those who have a family history of a psychotic illness, or those who have certain characteristics such as schizotypal personality, or possibly have certain types of genes, may increase the risk of developing a psychotic illness following the regular use of strong cannabis.”

Research increasingly shows that there is a strong link between psychosis and the use of cannabis, with young people having a particular vulnerability and susceptibility.

On physical health problems, the Royal College of Psychiatrists says:

“Even though the main risk to physical health from cannabis is probably from the tobacco that it is often smoked with, new research has found that the cannabis plant also contains cancerogenic mutagens that can affect people’s lungs.”

We now have evidence of potential physical harm caused by smoking cannabis, and the approach taken by this House over the years has been to discourage people from smoking and using substances that harm their physical health. There is emerging evidence of the physical harm caused by smoking cannabis, so there is a strong argument that we should be consistent by discouraging people, as much as possible, from smoking cannabis. That, as my right hon. Friend has said, could be done by legalising cannabis and giving people an open choice, but when there is compelling evidence of physical harm, it would be wrong to legalise a substance that we know to damage people’s mental health and, increasingly, their physical health.

Several issues have been raised about the medical use of cannabis. Cannabis is widely used by people who attend pain clinics—such people self-administer illegally obtained cannabis for symptom relief. At the moment, it is very difficult for medical researchers to research the potential benefits of some substances contained in cannabis in alleviating pain in palliative care or in other legitimate medical settings.

The hon. Member for Caithness, Sutherland and Easter Ross eloquently discussed Sativex, a drug used to treat multiple sclerosis. The drug remains a schedule 1 controlled drug, which means that under the Misuse of Drugs Act 1971 and in regulation there are no requirements on pharmacists to keep records or on the prescriber to write prescriptions in a form other than that required by the Medicines Act 1968—in other words, for prescription-only medications.

The Medicines and Healthcare Products Regulatory Agency has also issued the manufacturer of Sativex in the UK with a wholesale dealer’s licence and an importation licence for patients with MS. The Home Office has therefore been able to issue licences for such supplies, and has done so through a general licence that covers all doctors who apply on behalf of individual MS patients. Dispensing pharmacists are also covered by that licence, which is triggered by an application by the doctor to the Home Office Inspectorate. Supplies can be made directly from the company’s domestic stocks.

There is a challenging framework for the medicinal use of cannabis in this country, and it needs to be reconsidered. It was suggested earlier that we should consider changing cannabis from a schedule 1 drug to a schedule 2 drug, which would be consistent with opioids—doctors are able to prescribe, say, methadone as an alternative for someone who is being treated for heroin dependence. That merits some consideration, and I would be grateful if the Minister responded on that point. A number of studies in the United States have shown that cannabis has potential medicinal benefits for pain relief in palliative care, so will we in this country be able to consider some of those issues? If we can help patients use pain control better to manage the symptoms of terminal or progressive diseases or illnesses, that has to be a good thing. We would not want the unintended consequences of the current legal framework to get in the way of achieving that.

This is not a simple issue. I have looked at the evidence and, on balance, I am not currently persuaded that making access to a substance that is harmful to both physical and mental health legal, as opposed to decriminalised, would be a good thing. We need to make it easier to research the potential medical benefits of cannabis in pain control in terminal and progressives illnesses. Finally, there is a lot for us to do in the criminal justice system. There were encouraging words from the Secretary of State for Justice last week on the need to stop the cycle of reoffending by better supporting prisoners with mental illnesses or substance misuse challenges, including the misuse of cannabis and other drugs. We can help such people not by criminalising their activities but by supporting their rehabilitation and helping them to cope better with their substance misuse problems.