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“We do need to worry about young people”: Doctors reveal surge in psychosis linked to cannabis

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The number of Scots suffering mental illness linked to cannabis has surged since use of the drug was effectively decriminalised.

Figures reveal the number of users being hospitalised because of psychiatric issues has climbed by 74% since 2016 when police began warning those caught with the drug for their own use.

The admissions data has prompted experts to call for a reassessment of the risks posed by cannabis in comparison to Class A drugs and alcohol and urgent action to bolster support for users trying to give up.

Professor Jonathan Chick, medical director of a world-leading rehab clinic in the Borders, said the figures confirmed his experience, adding: “The eye has been taken off the ball with cannabis. We do need to worry about the numbers of young people presenting with psychosis and schizophrenia because of it.”

In January 2016, Police Scotland changed the guidance to officers, advising that simple possession of cannabis could be dealt with using a warning rather than a report to the Fiscal and possible prosecution.

Comparing the data from 2015/16 to the latest figures reveals the number of prosecutions has more than halved from 1,809 to 877 in 2019/20. However, drug-related hospital stays due to mental or behavioural problems linked to cannabis use rose by 74% from 1,191 to 2,067 last year. And in 2020/21, a record 1,263 new patients sought hospital treatment for a range of psychiatric disorders blamed on the drug, including schizophrenia.

A recent report by Public Health Scotland states: “There has been a notable increase in the percentage of [psychiatric hospital] stays attributed to cannabinoids in recent years, increasing from 9% in 2014/15 to 18% in 2019/20.”

Chick said the increasing potency of cannabis had led to an increase in people needing help at his Castle Craig clinic around five years ago but, he said, “first step” support services are already overwhelmed while his clinic rarely gets NHS referrals for cannabis.

He said: “We’re dealing with both dependence and psychosis. Often, where there has been a second or third psychotic breakdown, there has been hospital or police involvement because of incidents of self-harm or harm to others. These patients have terrifying thoughts.

“It is a paranoid psychosis where they can’t even go into the street without misinterpreting thoroughly innocuous cues as malevolent. It is a horrible experience.

“In some cases, people have used cannabis for 20 years and got by up till that point, but, typically, psychosis will occur within the first three to four years.

“Sometimes the damage is permanent in which case the treatment for schizophrenia involves living and working in safer environments and medication – though there is no medication that doesn’t come without effects such as weight increase, mental slowing and involuntary movements.”

Researchers in the US have bolstered the link between cannabis and mental illness. Recent analysis by McLean Hospital, Massachusetts, found that admissions due to cannabis-associated psychosis are up to 2.5 times higher in parts of the country where the drug has been legalised.

Meanwhile, Harvard Medical School studied 246 new psychosis patients aged 16-35 and discovered that a total of 78% had used cannabis. In all, 47% were currently or had been dependent on the drug – compared with 5% in the general young population.

The onset of the damage caused by cannabis was often swift. The typical age of first use was 15 with symptoms appearing between 17 and 19 and psychosis setting in between 19 and 21.

Chick added: “We receive regular small numbers of referrals from the NHS and social services for all addictions: alcohol, opioids, prescription drugs, but very rarely cannabis. We have fewer cannabis patients coming to us from the UK than we do from other countries, particularly the Netherlands, because the Dutch are more generous at funding treatment for dependence.

“Here, cannabis is considered more of a gateway drug. It is not contributing to the overdose deaths and doesn’t cause the acute physical damage of alcohol. So with limited budgets, residential treatment is prioritised for those whose conditions would otherwise cost more to treat.

“A middle-aged man with liver disease is seen as the priority over a teenager with two years of cannabis use. But that teenager may go on to need years of hospital treatment for psychosis.

“Health economics is a fine art – and it becomes finer still when there are fewer resources. All this conspires to hide the pernicious effect of cannabis use.

“We need a tiered approach to try to deal with the problem at an early stage with the least expense and disruption. But ‘step one’ services like counselling and advice are pretty much overwhelmed already.”

Since Scots police began warning users instead of charging them, the amount of cannabis seized has risen 60% from 984 kg to 1,570 kg and the number of plants 6% from 31,398 to 33,295.

Last week – in a case reflecting both the scale of cannabis cultivation in Scotland and also the difficulties in convicting those behind the industrial-scale farms – two men arrested after police raided one of the country’s biggest ever drugs factories walked free from court after it emerged they were victims of human trafficking.

Police had discovered “a very large and sophisticated” cannabis farm divided into 13 growing rooms and producing up to £9.5 million worth of the drug in a converted industrial building in Possilpark, Glasgow in November 2020.

Annemarie Ward, chief executive of the charity Faces & Voices of Recovery, said: “We’re still in the grip of this really worrying narrative that cannabis is about peace, love and opening your mind with no harm done. In fact, the current type is addictive and psychoactive with horrendous consequences.

“The cannabis myth has to be challenged but the preventive messages to children and young people are not loud or clear.

“And you cannot get people into services if they don’t exist. Between the police giving someone a warning for possession and that person further down the line turning up at hospital for treatment for psychosis, there is a massive vacuum.

“Every warning handed out should come with a referral to a local drugs centre where that person is assessed and given help where it’s needed – before it ever gets to the stage where they have to be admitted to hospital.”

The body produces natural cannabinoids, which are fatty acids that send messages within the brain, known as neurotransmitters. They spark chemical chain reactions that help produce feelings of reward linked to food and exercise, affect memory and co-ordination and may also influence sleepiness and pain.

Cannabis also contains dozens of cannabinoids which have the potential to trigger the same types of cascades in the brain. One of them, known as THC, is the substance that produces the drug’s well-known psychoactive effects and gets people high.

CBD is another – though this is far more benign, the one that is the focus of medicinal cannabis. However, research shows that THC damages the crucial links between brain cells.

These bridges in the brain’s neural network are burnt temporarily, potentially causing the classic hallmarks of psychotic episodes: hallucinations, delusions and voices in one’s head. But, over time, the damage can become permanent and the spells of detachment from the real world longer-lasting and more frequent.

Last year, German research also found a link with lung cancer, separate to the risk posed by tobacco smoke. Munich’s Ludwig-Maximilian University looked at those with a genetic liability to lifetime cannabis use and found that their risk of developing squamous cell carcinoma is 22% higher.

FAVOR and the Scottish Conservatives are backing a new Right to Recovery Bill at Holyrood which would give those with drugs problems a right to treatment.

Scotland has the worst drugs death rate in Europe, with a record 1,339 people dying in 2020. Last year, Malta became the first European country to make it legal to grow and possess cannabis for personal use.

So far, the UK Government – which retains the powers on prohibition – has resisted calls to follow suit but medicinal cannabis was, in effect, legalised here in 2018 where a specialist doctor prescribes it.

The Scottish Government said: “We have launched a national mission with an additional £50 million per year for services to help save and improved lives impacted by drugs of all types.

“The aim of the national mission is to get more people into treatment or recovery where they will receive the right treatment at the right time.

“We have been clear in our commitment to tackling the specific harms caused by the use of synthetic cannabinoids.”

It added: “A public health approach to substance use and harm prevention seeks to reduce harms and addresses the broader context of health outcomes and inequalities.”

Police Scotland Chief Inspector Anton Stephenson said: “Recorded police warnings in cases involving a single charge of possession of a controlled drug gives officers another tool to support those at risk of becoming vulnerable in our communities.

Issuing such a warning is not the only option available to officers dealing with people in these circumstances and officers can use their discretion to determine the best course of action.”

He added: “Our advice is simple: there is no safe way to take drugs, there is always a risk, and the only way of staying safe is to avoid drugs altogether.”


My happy, lovely son is gone. We only have a shell of him now and my heart is breaking

Alexander was 12 when he first smoked cannabis and by the time he was 14 he was undergoing psychiatric care after suffering hallucinations and threatening to kill
his mother.

His descent into serious mental illness came after he was first given the drug by friends, before buying it online from dealers and eventually selling it himself to fund his own habit.

Today, Alexander is 19, does not have the capacity to live alone and probably never will, says his mother. “He is so damaged by cannabis that he will not likely hold down a job, get married, drive a car or live independently and will miss out on all the lovely life events most of us will take for granted,” she said.

“Before he started smoking cannabis he was very keen on sports at school and would go running and swimming with his brothers.

“But within a few months of smoking cannabis he had become secretive, would go out as soon as he came home from school, spent a lot of time in his room and became isolated from us all.

“The happy son who had been open and sharing became a recluse, hiding a drugs habit from me.

“I discovered it all by finding drugs in his schoolbag and confronted him with it. Of course, he promised to give it up but only became more secretive and I could still smell it on him, and his behaviour worsened.”

It was only when Michelle, who lives in the Central Belt, accessed his social media accounts that she realised how bad his habit was.

“He was selling the drug to others so he could afford to buy it for himself. When he didn’t smoke cannabis or skunk, he would buy powerful cannabis oil to get the same or a stronger effect, which I feel triggered the psychosis,” she added.

“Alexander was so disturbed and psychotic at times he would think the dog was speaking to him. It all got too much when he wakened me one night threatening me with a glass. I had reached the end of coping with this on my own.”

Attempts to seek help from the family GP only resulted in assurances that many teenagers dabble in drugs but that it rarely led to long-lasting problems. “I could not get anyone to take us seriously and in desperation went to A&E at hospital where the consultant confirmed my son was mentally ill and needed to be admitted – sectioned under the Mental Health Act.

“After he was sectioned he spent almost two years in a psychiatric unit where he underwent drug treatment for psychosis. I visited him every day because it was so important to let him know we still cared for and loved him – and always would.”

“Alexander left hospital during the first wave of the Covid pandemic and has been living at home since, totally dependent on his family.

“When I asked the police to investigate the amount of drugs sold online they refused, and only seemed interest in what we all might think as bigger drugs. The son I had has gone, dead, killed by cannabis. He has been replaced by a shell and my heart breaks for him.”

Names have been changed.


The increasing potency means this is no longer a relatively safe drug

by Professor Sir Robin Murray 

There is a worldwide trend towards relaxing laws around cannabis use. Uruguay legalised it for recreational use in 2013, as did Canada in 2018, as well as 18 US states.

In Holland, cannabis can be bought in designated cafes while in Portugal, where cannabis use is decriminalised, the police just refer persistent users for counselling. In the UK, Sadiq Khan, the Mayor of London, is about to embark on a pilot trial of decriminalising cannabis in three boroughs.

Why do people like cannabis? THC, the active ingredient, causes a “high” that people enjoy. Forms of cannabis such as marijuana or hash used in the 1960s contained less than 4% THC. However, these traditional types have been replaced by stronger varieties. In the UK, skunk now dominates the market; it contains on average 15% THC.

If we think of marijuana as being the cannabis equivalent of lager, skunk is the equivalent of vodka.

The increased potency of cannabis means it is no longer a relatively safe drug. I have been a psychiatrist since the 1970s and for the first 25 years I didn’t bother to ask patients if they smoked cannabis. It didn’t seem to cause problems.

However in the late 1990s I started seeing young men admitted to hospital acutely psychotic with paranoid delusions and hearing voices; relatives would ask me, “Could their illness have anything to do with the fact they smoke cannabis all day long”.

I would say no. How wrong I was! There have now been more than a dozen research studies that show young people who use potent forms of cannabis have an increased risk of developing schizophrenia and other psychotic illness.

The risk in daily users is increased between five and 10 times. Of course, the vast majority of people using cannabis do not develop a psychotic disorder but people who start using as teenagers are vulnerable, as are those with a family history of psychiatric problems.

Increased potency of cannabis means the UK now has among the highest rates of psychosis in Europe. The frequency of schizophrenia has trebled in London in the last 50 years and much of this is due to cannabis use. In some places one third of all the people admitted to hospital with psychosis developed the illness because
of cannabis.

Is it inevitable that legalisation of recreational cannabis will result in more addiction and psychosis? In theory it should be possible to legalise cannabis in ways that do not increase potency and prevalence of use; but so far experience in North America is not encouraging. In those US states that have legalised cannabis, the price has fallen, potency shot up and both cannabis use and addiction have increased.

I had thought decriminalising but not legalising might be a good option. This is what was done in Portugal. However, in the 15 years following decriminalisation, rates of hospitalisation for psychotic disorders increased by an astonishing 29 fold; the percentage of patients with psychotic disorder recorded as abusing cannabis use, rose from less than 1% to 10%.

As with the initial reports more than 60 years ago of a causal association between cigarette smoking and lung cancer, the cannabis industry denies or minimises the evidence that cannabis use increases risk of psychosis.

However, eventually public health campaigns were successful in persuading people not to smoke cigarettes.

Our best hope to avoid an epidemic of psychosis is to have similar education about the risks of high potency cannabis.


It’s not their in-tray and it’s not their kids: Former police chief on why politicians have failed young Scots drug users

Graeme Pearson is the former head of the Scottish Crime and Drug Enforcement Agency and an ex-Scottish Labour Shadow Justice Secretary

The uncomfortable truth is that we’ve known for a long time about the damage that cannabis can cause.

Back in 2007, the Scottish Crime And Drug Enforcement Agency held a conference at which we heard the warnings from those treating patients with mental illness brought on by this drug. The psychoses and violence, it was all forecast and it has now delivered.

In all my time, from when I was in the drugs squad in the 1970s to my time as boss of the agency in the 2000s, I never knew an officer who thought someone caught with a minor quantity of cannabis should go to jail.

But the illegality of the drug opens the door to opportunities to intervene to help that person leave cannabis behind.

The 2016 guidance to replace prosecution with warnings was not a bad thing in itself,
but it was just a headline; there were no nuts and bolts behind it to make the machine work properly.

There are some parts of Scotland where you could stop the same person every day for a year and give them a warning.

So what? Where is the education and the support mechanisms at ground level for these people? You’ll probably end up waiting eight or nine months for an appointment to see someone who could help you.

I’ve been to drug treatment centres that are no better than dosshouses, thrown up on the cheap. I wouldn’t leave my dog there.

We have to get away from the idea that cannabis is somehow harmless. It is a dangerous substance, particularly for young boys whose brains have yet to fully develop and are being caused irreparable lifelong damage.

In some areas, it has become the norm for children to smoke it at lunchtime. Their interest in education falls away, they become beyond educating and then unemployable – and the rest is history.

Unfortunately, there are few photo opportunities or votes in sorting out the mess and few senior politicians, police officers or chief executives have dirtied their hands with drugs or organised crime so there is very little understanding of the scale and nature of the problem.

It’s not their in-tray and it’s not their kids.