Cannabis myth debunked: Adding tobacco will NOT make you more stoned - but will help to sharpen memory, reveals first study of its kind

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The myth that smoking marijuana with tobacco will make users more stoned has been debunked by scientists.

Cannabis users across the world have long believed that sprinkling a handful of tobacco in with the herb improves the high.

But in the first study of its kind, researchers delving into how both substances interacted when inhaled together found no such effects.

However, they did note that mixing the two together may help to lessen the memory impairment caused by smoking cannabis.

The new University College London research suggested this could be because nicotine has previously been proven to sharpen the mind.

As legalisation of cannabis becomes prevalent, researchers said it is essential that any changes in its policy consider the interrelationship between tobacco and marijuana.

Researchers at University College London have debunked the myth that smoking marijuana with tobacco will make users more high

Researchers also found that smoking cannabis and tobacco together can temporarily increase blood pressure and heart rate.

Experts said the findings are worrying, considering the long-term health dangers that are already known about smoking tobacco-related products, including heart disease and various forms of cancer.

Lead author Chandni Hindocha, of the university's clinical psychopharmacology department, said: 'There's a persistent myth that adding tobacco to cannabis will make you more stoned, but we found that actually, it does nothing to improve the subjective experience.

'Surprisingly little research has been done on how tobacco might alter the effects of cannabis.

'As cannabis gets legalised in more countries, it is essential that any changes in cannabis policy consider their interrelationship.'

Professor Val Curran, who was also involved in the research, added: 'There is a clear public health implication here, suggesting that smoking tobacco with cannabis does not improve the stoned feeling but is still worse for physical health.'

How the study was carried out 

For the study, 24 cannabis users took part in four sessions of smoking different joints. They were rolled with cannabis and tobacco, cannabis and a placebo, tobacco and a placebo, or just the placebo of both.

Their memory was tested by having to recall passages of prose, which they heard before and after smoking. They also had to complete a small task to assess their spatial working memory.

Heart rates and blood pressure was taken both before and after smoking each joint, while volunteers self-reported their mood and experiences.

Where do people mix cannabis with tobacco? 

Many people in Europe choose to mix tobacco and marijuana together when rolling joints in order to make their supply of the drug last longer.

Others do so in the belief that they will get a bit of an extra kick from tobacco, which contains nicotine – a drug that releases 'feel good' chemicals in the brain.

The latest Global Drug Survey showed that up to 90 per cent of European cannabis users smoke it with tobacco.  

But this method of smoking the drug is less common in the US, with many instead choosing to inhale cannabis on its own. 

The new finding that tobacco has the ability to reduce the memory-impairing effects of cannabis may be part of why people add it to their joint, the researchers said. 

Scientists did note that mixing the two together may help to lessen the memory impairment caused by smoking cannabis

'A fascinating piece of research'

Ian Hamilton, a cannabis researcher based at the University of York who wasn't involved in the study, told MailOnline: 'This is a fascinating piece of research and clearly the impact of combing tobacco and cannabis needs to be investigated further. 

'We don't know why this habit of using these two drugs has persisted for so long, in the past it was believed to be due to making your cannabis joint go that bit further. 

'But perhaps this new research offers an insight into more complex reasons for rolling a joint with tobacco. 

'Overall even if memory is improved this is offset by the greater risk that tobacco poses to health. There are safer ways of improving memory and recall.'

It comes after a Georgia Regents University study in 2015 found that nicotine supported learning and memory ability.

This may explain why the new study participants who smoked both substances had an easier time recalling a phrase than when they smoked marijuana alone.

However, the experts claim the addition of nicotine can add to the cardiovascular risk of smoking marijuana.

Scientists are under no illusion that tobacco use is dangerous, with it being the single most preventable cause of death in the world. 

Tobacco products caused around 101,000 deaths in the UK in 2010 and around 480,000 deaths annually in the US.

But the medical community is still divided over the pros and cons of smoking cannabis as they race to thoroughly understand the drug's long-term effects.

Experts taking a closer look on the effects of pot have found both benefits and problems.

German researchers claimed cannabis could possibly delay the onset of Alzheimer's disease.

Their study examined elderly mice and found their mental power improved dramatically after they were given THC, the psychoactive part of marijuana that makes users 'high'.

A potential downside to marijuana comes from new research by Columbia University.

They found smoking weed on a regular basis drives up the risk of severe gum disease - and could cause teeth to fall out. 

The UCL study authors warn their research should be a warning sign that increasingly relaxed marijuana laws in the US could have serious oral health implications.

In the US, cannabis use for both medical and recreational purposes is legal in Colorado, Washington, Alaska, Oregon, Nevada, California, Maine and Massachusetts.

Marijuana is still not legal in the UK and can carry a five-year prison sentence for anyone found in possession of the substance.