Cannabis WON'T harm your health as long as you stick to one small joint a week, scientists claim

• Users are unlikely to suffer health effects from a small dose, scientists say
• Only pregnant women or those with severe mental illness are vulnerable
• Safer Use Limits app launches in a bid to reduce harm to drug takers
• Safer limits guidelines on MDMA, cocaine and ketamine are to follow

By Madlen Davies

One small cannabis joint a week will not harm your health, scientists have claimed.

Experts gave the advice as they launched the world's first ever guidelines on how to take drugs safely.

Cannabis users are unlikely to encounter long-term health issues if they smoke such a small dose, according to the ground-breaking guide.

While the only way to avoid all harm is to not use drugs, leading drugs experts have launched the app in a bid to reduce harm in those who indulge in illegal substance use.

Scientists at Kings College London have launched the new Safer Use Limits app to reduce harm among drug users. It aims to inform people of the risk their drug-taking poses to their health

The app reveals cannabis users are unlikely to encounter long-term health issues if they smoke just one small joint a week

Extensive research of more than 40,000 cannabis users found one low dose joint a week makes long-term health problems unlikely.

Only those who are pregnant or suffering a severe mental illness are more vulnerable, according to an addiction specialist.

Dr Adam Winstock, a consultant psychiatrist and addiction medicine specialist, is launching the Safer Use Limits app, which is based on the experiences and results of the Global Drugs Survey.

It advises cannabis users about how to reduce their risk of ill-health by quizzing them on the quantity and frequency they use the drug - much like the Government's alcohol consumption guidelines.

Dr Winstock, a lecturer at King's College in London, said: 'The Global Drug Survey states categorically that the only way to avoid all harm from drug use is to not use them whatsoever.

The Global Drug Survey states categorically that the only way to avoid all harm from drug use is to not use them whatsoever. However, it's not a very practical goal for people who like to indulge in drugs 

Dr Adam Winstock

'However, it's not a very practical goal for people who like to indulge in drugs.

'The reality is that the risks of experiencing harm from using drugs can actually be massively reduced for most people with the right set of advice.

'We've spent the past few years looking at the data from drug users around the world in an effort to settle on what that advice should be.'

The new research by the Global Drugs Survey found four in ten cannabis users smoked it more than 100 times a year. 

Such usage puts them at risk of lower health harm, with potential impacts upon memory, mood, lung health, mental health and motivation.

Meanwhile, a staggering one in 20 smoked cannabis every day - putting them at very high risk of dependence, withdrawal, negative impact on interpersonal relationships, ageing and motivation.

In the last 12 months, one per cent of users have even been hospitalised due to their cannabis consumption. 

Safer limits guidelines on MDMA, cocaine and ketamine will follow in the coming months too.

Wayne Hall, professor, director and inaugural chair at the Centre for Youth Substance Abuse Research at The University of Queensland, hopes advice drawn from the app could be more persuasive to cannabis users than advice from medical professionals.

He said: 'The world's first safer drug use limits guidelines will help people use cannabis better and understand the relationship between how much cannabis they use and the risks they expose themselves to.

'Global Drug Survey's Safer Use Limits Guidelines for Cannabis is a useful way to advise regular cannabis users about how to reduce the risks of their drug use.

'Advice based on the experience of users surveyed in GDS may be more persuasive than conventional medical advice.'