Cannabis use in Switzerland 2015-2045: A population survey based model

Marc Vogel; Carlos Nordt; Raoul Bitar; Lukas Boesch; Marc Walter; Erich Seifritz; Kenneth M Dürsteler; Marcus Herdener

doi:10.1016/j.drugpo.2019.03.008

Cannabis use in Switzerland 2015-2045: A population survey based model

Int J Drug Policy. 2019 Jul:69:55-59. doi: 10.1016/j.drugpo.2019.03.008. Epub 2019 Apr 25.

Authors

Marc Vogel¹, Carlos Nordt², Raoul Bitar², Lukas Boesch², Marc Walter³, Erich Seifritz⁴, Kenneth M Dürsteler⁵, Marcus Herdener²

Affiliations

¹ University of Basel Psychiatric Hospital, Division of Addictive Disorders, Wilhelm Klein-Strasse 27, 4002, Basel, Switzerland. Electronic address: Marc.Vogel@upk.ch.
² Centre for Addictive Disorders, Department for Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8001, Zurich, Switzerland.
³ University of Basel Psychiatric Hospital, Division of Addictive Disorders, Wilhelm Klein-Strasse 27, 4002, Basel, Switzerland.
⁴ Department for Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8001, Zurich, Switzerland.
⁵ University of Basel Psychiatric Hospital, Division of Addictive Disorders, Wilhelm Klein-Strasse 27, 4002, Basel, Switzerland; Centre for Addictive Disorders, Department for Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8001, Zurich, Switzerland.

PMID: 31030906
DOI: 10.1016/j.drugpo.2019.03.008

Abstract

Background: Alternative cannabis regulation models are discussed and implemented worldwide. A baseline scenario under the assumption of no policy or market changes may prove useful to forecast cannabis use and treatment demand and evaluate changes in legislation.

Methods: Based on data of the Continuous Rolling Survey of Addictive Behaviours and Related Risks on cannabis use, age, gender and nationality from 2011 to 2015, we used general estimating equation analysis to model lifetime and 30-days prevalence from 2015 to 2045 in Switzerland accounting for demographic trends.

Results: Lifetime prevalence of cannabis use is projected to grow from 28.3% (CI 95% 27.8-28.8) in 2015 to 42.0% (CI 95% 41.0-43.0) in 2045. 30-days prevalence would increase slightly from 2.70% (CI 95% 2.53-2.88) to 3.39% (CI 95% 3.11-3.66). Due to population growth, absolute numbers with past 30-day cannabis use are estimated to increase from 202,784 (CI 95% 189,534-216,035) to 314,302 (CI 95% 288,504-340,100). Among those aged under 30 years no substantial change in lifetime and 30-days prevalence of cannabis use is projected. Larger changes are estimated to occur in the age group 30+. The mean age of past 30-day cannabis users would increase for men with Swiss nationality from 30.3 to 38.7 years.

Discussion: Population-based survey data and demographic projections can be used to develop baseline scenarios of future cannabis use. Assuming no changes in cannabis legislation, growing absolute numbers of users will likely increase treatment demand. Cannabis use is estimated to increase among the group aged >30 years, which is currently underrepresented in clinical treatment and research. Our findings highlight the need for prospective baseline scenarios to evaluate the impact of legislative changes on cannabis use. Moreover, in Switzerland effective prevention and treatment interventions for cannabis use disorders are required even if cannabis legislation remains unchanged.

Keywords: Demography; Drug policy; Marijuana; Prevalence; Substance use; THC.

MeSH terms

Adolescent
Adult
Aged
Aged, 80 and over
Drug Users
Female
Forecasting
Humans
Male
Marijuana Abuse / drug therapy
Marijuana Abuse / epidemiology*
Marijuana Abuse / prevention & control
Marijuana Smoking / trends*
Middle Aged
Prevalence
Surveys and Questionnaires
Switzerland / epidemiology
Young Adult