Approximately one in 13 adults in Great Britain are estimated to have used cannabis in the past year, approximately four times as many among cigarette smokers as non‐smokers, according to the calculations of a new cross‐sectional national online survey.
The study, published in the journal Addiction, was based on survey results from February-March 2020 of adults aged ≥18 years (n=12,809), with statistically weighted prevalence estimates computed to ensure representativeness.
The researchers estimated the prevalence of cannabis use, frequency of use and routes of administration among tobacco smokers and self-identified non‐smokers and investigated mental health problems among non‐users, tobacco‐only, cannabis‐only and co‐users of both substances.
A total of 7.1 per cent of the study sample reported having used cannabis in the past year.
Tobacco smokers had greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non‐smokers (past year: 4.7%; adjusted OR [aOR]=10.07 [95% CI, 8.4‐12.0]; daily: 0.7%; aOR=24.6 [95% CI, 17.96‐35.55]).
Co‐administration with tobacco was common (46.2% of non‐smokers, 80.8% of tobacco smokers).
Co‐users reported the highest prevalence of any treatment for mental health problems (54.2%) in comparison to cannabis‐only (45.8%), tobacco‐only (33.2%) and non‐users (22.7%; all P≤.05).
Cannabis was disproportionately more used among younger people, with 70 per cent of those who had used cannabis in the last year aged below 39 years.
One of the study’s authors Hannah Walsh, from King’s College London, said the findings raised concerns that non-smokers were unaware that smoking cannabis carries similar health risks to tobacco. “It is extremely concerning that there are hundreds of thousands of people who do not see themselves as ‘smokers’ but are none-the-less smoking every week. It is possible that they do not realise they are putting their health at risk. It’s also a concern that people may be unwittingly establishing a tobacco addiction as a consequence of their cannabis use.”
