The research is in… Using cannabis (marijuana) can affect memory, concentration, decision-making and cause schizophrenia. Scientists at the University of Montreal have found that children who smoke the drug perform worse at school because the effects result of using cannabis persist well beyond the period of being ‘high’. Adults who use the drug could also suffer at work or find their driving ability impaired.

Marijuana is the most popular psychoactive substance in the world, and the second mostsmoked substance after tobacco. According to the Center for Disease Control and Prevention (CDC), marijuana is the most widely used federally illegal drug in the US, and 18% of Americans have used it at least once. Marijuana smoke contains many of the same toxins as tobacco smoke, and it can harm lung tissues and damage and scar small blood vessels. Marijuana has overtaken cigarettes in the US, with only 13% of US adults smoking cigarettes in 2020.

Cannabis is an illegal Class B drug in Britain — possession can result in a five year prison sentence and those who supply the drug can face up to 14 years in jail.

The drug is widely used for recreational purposes and makes users feel relaxed. But smoking it can also lead to feelings of panic, anxiety and paranoia. I fact, paranoia can remain a permanent problem years after a user stops using it. It can also contribute to mental health problems among people already suffering from them, or increase users’ risk of psychosis or schizophrenia. Many users admit to bouts of paranoia which can persist years after they stop using the drug.

On the upside, the drug can also alleviate depression, anxiety and stress, but heavy use can worsen depression in the long term because the brain’s ability to let go of bad memories is reduced. Marijuana is now prescribed for medical uses in more than half of US states, where it is used to combat anxiety, aggression and sleeping problems. However, coming off marijuana often makes users more aggressive and Anxious.

Coming off the drug is usually followed by sleeplessness until the brain stabilises again, a process which usually takes a few days.

The University of Montreal review, published in the journal Addiction, concluded that impairments ‘may be worse in regular and heavy users’.

The Montreal researchers analysed existing cannabis studies involving more than 43,000 people and looked at how the drug affected memory, learning, attention, language, processing speed, and motor function. They also looked at the extent to which cannabis affects cognitive performance immediately after taking it and in the longer term. They also looked at a range of smoking habits — from daily use to abstinence.

Frequent heavy use was found to hamper decision-making, flexible thinking and selfcontrol. Regular use hampered the ability of people to control their behaviour, and left them less able to make ‘appropriate decisions’. The research also showed adults given THC — the psychoactive substance that provides the ‘high’ — performed worse in memory tests.

Not all of the studies agreed, with some of the analyses finding no effect on memory caused by regular cannabis use. However, most users were found to have problems concentrating and difficulties remembering and learning, which may have considerable impact on users’ daily lives.
Nonetheless, Cannabis use in youth does lead to reduced educational attainment, and, in adults, to poor performance at work and dangerous driving. These effects appeared to be worse in regular and heavy users.

It can also exacerbate mental health problems among people who are already troubled, and increase users’ risk of psychosis or schizophrenia. Research has previously shown a strong link between cannabis and mental illness.

In Scotland, admissions to psychiatric hospitals among cannabis users have soared by 74% since the drug was effectively decriminalised six years ago, from 1,191 in 2015/16 to 2,067 in 2019/20. Part of the reason is thought to be the change in Scottish police guidance in January 2016, resulting in those found in possession of cannabis being issued with a warning rather than prosecution.

The overall effect was that the number of prosecutions halved, but a Public Health Scotland report showed that psychiatric admissions for cannabis users had doubled between 2014 and 2020. A record 1,263 patients in Scotland sought hospital treatment for psychiatric disorders, including schizophrenia, as a result of smoking cannabis.

In cases of a second or third psychotic breakdown, there has been hospital or police involvement because of self-harm or harm to others. Those suffering from paranoid psychosis can’t even go out without misinterpreting thoroughly innocuous cues as malevolent. Typically psychosis will occur within the first three to four years of use. The damage is often permanent, in which case, treatment of schizophrenia involves medication
and residential care.

NHS figures will add pressure on the UK Government to resist calls to decriminalise cannabis.

A US study found that cannabis-linked psychosis admissions were 2.5 times higher in areas where the drug has been legalised. Harvard Medical School studied 246 new psychosis patients aged 16 to 35 and found that 78% had used cannabis.

The worse news is that teenagers who only occasionally use cannabis are just as likely to develop schizophrenia as daily smokers. Researchers in the Caribbean at the Saint James School of Medicine in Arnos Vale, St Vincent and the Grenadines, reviewed more than 590 papers looking at cannabis use in children aged 12 to 18. There, the results showed that smoking the drug at low frequencies came with the same six-fold increased risk of developing schizophrenia as using he drug daily.

It is vital teenagers avoid using the drug while their brains are still developing. NHS figures show cannabis use in people aged 16 to 24 is rising in England and Wales, with 33% admitting having used it in 2020, compared to only 30% in 2016. Data has revealed psychiatric hospital admission among cannabis users soared 74% since the drug was effectively ‘decriminalised’ in Scotland.

Another review, published in the Journal of Clinical Psychology, included 591 studies from 2010 and 2020 about cannabis use in adolescents from across the globe.

Researchers classified cannabis users into two groups:

1. low frequency users — smoking twice a week or less, and
2. higher frequency users — who smoke daily or nearly every day.

Using statistical analysis, they compared the groups’ chances of developing schizophrenia compared to teenagers who never smoked the drug. The chances of getting the mental disorder were six times higher in both groups, but they did not specify how long it usually takes to develop the disorder after starting smoking the drug.

The frequency of use among high and low-frequency users is similar in both men and women. Both high and low-frequency marijuana usage were associated with schizophrenia. Schizophrenia tends to occur in men in their late teens and early 20s, and in the late 20s to early 30s in women — although it can develop at any age for either gender.

Adam Winstock, the founder of the Global Drugs Survey and honorary Professor of Clinical Medicine at University College London, said the study showed the need for caution around cannabis use at younger ages. That is putting it mildly!

Professor Jonathan Chick, of Castle Craig Hospital, a private rehabilitation centre in Peeblesshire, said lawmakers have taken their eyes off the ball with cannabis legislation. He said the number of young people suffering psychosis and schizophrenia because of cannabis use is a ‘worry’.

Despite numerous studies linking the two, scientists have yet to discover exactly how the drug leads to the condition. And other research has suggested the drug itself may not be enough to cause serious mental disorders. A separate study by Harvard researchers in 2014 of cannabis users with and without a family history of schizophrenia suggested cannabis use alone does not result in the disorder. Even so, the risk of developing the disorder was higher in those with a family history, regardless of cannabis use.

Dr Lynn DeLisi, one of the authors of the paper, told the New York Times: “My study clearly shows that cannabis does not cause schizophrenia by itself. Rather, a genetic predisposition is necessary. It is highly likely, based on the results of this study and others, that cannabis use during adolescence through to age 25, when the brain is maturing and at its peak of growth in a genetically vulnerable individual, can initiate the onset of
schizophrenia”.

MARIJUANA / CANNABIS SCHIZOPHRENIA

Schizophrenia is a chronic and severe mental disorder that affects how a person thinks, feels, and behaves. People with schizophrenia may seem like they have lost touch with reality.

The causes of schizophrenia are not fully understood but it is believed to be a mix of inherited genes, abnormalities in brain chemistry, and/or possible viral infections and immune disorders.

Symptoms of schizophrenia usually begin between ages 16 and 30. It is rare for children to have schizophrenia.

The symptoms of schizophrenia fall into three categories: positive, negative, and cognitive.

Positive symptoms are disturbances that are ‘added’ to the person’s personality and include:

• Hallucinations
• Delusions
• Thought disorders (unusual or dysfunctional ways of thinking)

Negative symptoms are capabilities that are ‘lost’ from the person’s personality and include:

• ‘Flat affect’ (reduced expression of emotions via facial expression or voice tone)
• Reduced feelings of pleasure in everyday life
• Difficultly beginning and sustaining activities

Cognitive symptoms are changes in their memory or other aspects of thinking and include:

• Trouble focusing or paying attention
• Problems with ‘working memory’
• Poor ability to understand information and use it to make decisions

Figures suggest around only 1% of the world population suffers from schizophrenia.

Source material: National Institute of Mental Health

PAIN MANAGEMENT

Despite pain being one of the most popular reasons for using cannabis, it has no effect on pain relief — in fact cannabis is no more effective than a placebo.

A September 2021 review looked at more than a dozen studies in 11 countries involving 1,459 people over the previous 20 years. Researchers observed no significant difference between cannabis and a placebo for reducing pain.

Official figures show around a fifth of marijuana users in the US are prescribed medical cannabis. Estimates suggest a quarter of all Americans use CBD oil, with 64% of them using it for pain relief. Yet researchers at Cleveland Clinic found that cannabis users were significantly more likely to suffer pain after surgery!

The cannabis revolution in the US has seen more than half of states legalising the drug for medical reasons, including for the treatment of pain. Twenty one states have permitted its use recreationally.

Researchers from the Karolinska Institute in Sweden looked at 20 previous studies, the majority of the experiments being carried out in the US, UK and Canada, but included data from Israel, the Netherlands and the Czech Republic. A variety of pain conditions were included, such as nerve damage and multiple sclerosis. A range of cannabis products, including THC, CBD and synthetic cannabis, were being taken as pills, sprays, oils as well as smoked. The results revealed that pain intensity significantly reduced with cannabis but also as a response to a placebo.

The research found that a meta-analysis showed that pain was rated as being significantly less intense after treatment with a placebo, with a moderate to large effect from person to person, adding that “In line with general principles of human perception, expectations of (possible) pain relief can modulate sensory processing and thereby reduce the perception of incoming nociceptive signals.”

The review also noted that a lot of participants could tell the difference between cannabis and a placebo, even though they smelled, tasted and looked the same.

The researchers’ findings corroborated the 2021 meta-analysis which found that where the researchers or participants didn’t know who was receiving the marijuana led to higher placebo responses.

The report was published in the Journal of the American Medical Association

A multi-state study found that pregnant women who live in US states with liberal cannabis laws are substantially more likely to use the drug than women who live in places with more restrictions. Significantly, smoking the drug while expecting puts the unborn baby at risk of premature birth and low birth weight or even stillbirth, as well as long-term brain issues with development.

The health risks of marijuana and cannabis are well known. Around 48 million Americans smoke cannabis at least once a year, according to official estimates. Marijuana is the thirdmost commonly used drug in the US after alcohol and tobacco, and this figure is rising as more states legalise the drug.

Even so, evidence from the Substance Abuse and Mental Health Services Administration is growing over its health risks — particularly in young adults, including:

Brain damage: It can cause a permanent loss of IQ because it hinders brain development and could even have lasting cognition effects in young adults;

Mental health: It has been linked to increased rates of suicide as well as psychiatric disorders such as depression and anxiety, although it is unclear if marijuana is the cause;

Daily life: Surveys link it to more problems in careers and maintaining healthy relationships;

Driving: Those who drive under the influence have slower reactions and less coordination, research shows.

Marijuana and Lung Disease

People who smoke marijuana are more likely to develop lung disease than cigarette smokers.

Researchers at the University of Ottawa looked at 150 adults around 50 years old and were either pot smokers, tobacco smokers or non-smokers. Three-quarters of marijuana users had emphysema, a lung disease which leaves sufferers struggling to breathe. Just one in 20 non-smokers suffered from the condition, which kills more than 120,000 Americans every year.

Study author Dr Giselle Revah, a cardiothoracic radiologist and assistant professor was surprised by the results, saying that the findings suggested marijuana affects the lungs considerably more than tobacco. The researchers noted that tobacco cigarettes are usually filtered, whereas marijuana is smoked unfiltered, meaning that much more smoke is inhaled.

One of the limits of the study was that most cannabis users were also either current or former tobacco smokers, meaning damage might have already been done. In addition, the  study did not distinguish between joints (purely marijuana) or blunts which also contain tobacco. The findings come at the same time as states legalise the drug.

In the latest study, researchers from the University of Ottowa compared chest CT scans of 56 marijuana smokers with 57 non-smoking controls and 33 tobacco-only smokers. Fifty of the 56 marijuana smokers also smoked tobacco.

They found that 75% of the marijuana smokers had emphysema, in contrast to 67% of those who only smoked tobacco. Of the non-smokers, only 5% had emphysema.

Paraseptal emphysema was the main type of emphysema the researchers found in marijuana smokers, where tiny ducts connecting air sacs in the lungs become damaged.

Inflammation of the airways and gynecomastia (enlarged male breast tissue due to an imbalance of hormones) were also more prevalent in marijuana smokers than non-smokers. Gynecomastia was found in 38% of marijuana smokers, but in only 11% of tobacco smokers. Only 16% of the control group had enlarged male breast tissue.

The study found no difference in coronary artery calcification (a build up of calcium which can be an early sign of coronary artery disease) between age-matched groups of marijuana smokers and tobacco-only smokers.

These results are somewhat surprising because patients in the tobacco-only group had been smoking for a longer period of time. The fact that marijuana smokers, some of whom also smoked tobacco, had additional airway inflammation and chronic bronchitis suggests that marijuana has additional effects on the lungs.

The results were still significant when compared to the non-age-matched groups, including younger patients who smoked marijuana and who presumably had less lifetime exposure to cigarette smoke.

It has been suggested that smoking a marijuana joint deposits four times more particulates in the lung than an average tobacco cigarette. It is possible that these particulates are airway irritants.

More breathing problems could be due to the way marijuana is smoked. Marijuana tends to be inhaled for longer than tobacco smoke.

Further research could investigate the effects of different inhalation styles, such as through a bong, a joint or a pipe.

The research was published in the journal Radiology.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Chronic obstructive pulmonary disease (COPD) describes a group of lung conditions that cause the airways to narrow and become inflamed. These include bronchitis, which affects the airways, and emphysema, which impacts the air sacs, making it harder to move air in and out as you breathe.

According to the British Lung Foundation, around 1.2million people in the UK are diagnosed with COPD. In the US, 16million people suffer from COPD, according to the Centers for Disease Control and Prevention.

COPD usually develops because of long-term damage to the lungs from smoking or air pollution. Jobs where people are exposed to fumes, dust and chemicals also raise the risk. COPD also appears to run in families. A rare genetic condition called alpha-1-antitrypsin deficiency makes people susceptible at a very young age.

Symptoms include:
Breathlessness during day-to-day activities, like walking

• Persistent cough
• Wheezing in cold weather
• Producing excess phlegm

In severe cases, sufferers can lose their appetite, develop swollen ankles, experience weight loss and even cough up blood. COPD is incurable and the damage to the lungs cannot be reversed.