An estimated 1.2 million people in Great Britain use cannabis daily or near daily – considerably more than official estimates have suggested – according to a new study led by researchers at the University of Bath and King’s College London.

Published in Addiction, the study analysed responses from 25,537 adults who took part in the Action on Smoking and Health (ASH) Smokefree Great Britain survey in 2023 and 2024. Of these, 7.2% said they had used cannabis in the past year, and around a quarter of that group (24.2%) said they used it daily or near daily.

The study’s co-lead authors, Dr Elle Wadsworth from the Department of Psychology at Bath and Dr Hannah Walsh from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, say the 1.2 million estimate is considerably higher than the figure of around 470,000 adults in England and Wales reported by the Crime Survey for England and Wales.

They believe the difference is partly explained by how cannabis use is measured. Their survey includes people who use cannabis nearly every day as well as every day, whereas the Crime Survey counts daily use only. This does not necessarily mean frequent cannabis use has increased. Instead, it suggests there may be more people using cannabis daily or near daily than previously thought.

Not just a young person's habit

Cannabis consumption is often seen as a young person’s habit – and indeed, 18 to 24-year-olds were the most likely in the study to have used cannabis in the past year. However, a different picture emerges when it comes to frequent use.

Among those who had used cannabis, people aged 25 and over were more likely to use it daily or near daily than those aged 18 to 24. Cannabis users aged 35 to 54 were around twice as likely to use it daily or near daily as those aged 18 to 24.

Previous research has linked more frequent consumption to a greater risk of harms, including cannabis use disorder (where cannabis use leads to significant distress or impairment), psychosis and respiratory problems.

Dr Elle Wadsworth, co-lead author from the Department of Psychology at Bath, said: “Knowing whether someone uses cannabis or not only tells part of the story, because someone who uses cannabis once or twice a year is very different from someone who uses it every day. We chose to look at frequency of use so that we can better understand patterns of consumption and identify people who may be more likely to benefit from support.”

Dr Hannah Walsh, co-lead author and Research Associate at King’s IoPPN, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, said: “Our findings suggest this pattern is more common among people in mid-life, people out of work and people who also smoke tobacco. This gives a much clearer picture of who might benefit most from support, for example, those out of work, or those who access stop smoking services.”

Daily cannabis consumption more common among tobacco smokers

Among people who had consumed cannabis in the past year, 35% of those who also smoked tobacco used cannabis daily or nearly every day, compared with 15% of those who did not smoke tobacco.

Daily or near daily cannabis consumption was also more common among people who smoked cannabis, either with or without tobacco, than among those who consumed it in other ways, such as through edibles or vapes (29% compared with 13%), and among people who weren’t in work compared to those who were (37% compared with 21%).

Gender, ethnicity, region and social grade were not linked to daily or near daily consumption once other factors were taken into account.

Hazel Cheeseman, Chief Executive of ASH, said: “This research challenges some common assumptions about cannabis use. While younger adults are more likely to use cannabis, frequent use is more common among older age groups and among people who smoke tobacco.

“Smoking cannabis, especially when mixed with tobacco, exposes people to health risks and can make it harder to break free from nicotine addiction. Stop smoking services have an important opportunity to identify people who also use cannabis and offer support that reflects their needs. Equally, drug treatment services can and should engage with people about their tobacco use.

“The findings highlight the close relationship between tobacco smoking and cannabis use and the need for a more joined-up approach to helping people reduce the harms from both.”

Elle Wadsworth is supported by a fellowship from the Society for the Study of Addiction.