RecruitingNot Applicable

Pilot-Study for the Comparison of Biomarkers Between Regular Cannabis Users and Non-Users

Switzerland120 participantsStarted 2025-12-19

Plain-language summary

The relevance of driving under the influence of cannabis is becoming increasingly important in the context of legalization. However, the measurement of tetrahydrocannabinol (THC) blood concentration is an inadequate marker for assessing driving impairment. Currently, there is no reliable marker available for estimating the time of last cannabis inhalation, which would provide a promising tool for regulating driving under the influence of cannabis. This pilot study aims to explore potential biomarkers and factors that could approximate the timing of the last cannabis inhalation, with emphasis on the potential explanation of interindividual differences in THC pharmacokinetics and -dynamics. The results will assist future research aimed at improving the ability to distinguish between impaired and unimpaired cannabis users in road traffic. These findings are of significant importance for road safety and for society at large, as they may provide more objective markers for cannabis inhalation, thereby permitting a methodologically sound evaluation of driving under the influence of cannabis.

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Experience of smoking cannabis products, on average once a week. This may be in combination with tobacco. * Age 18-65 years Possession of driving license in at least one of the categories A, B, A1; B1, F, G or M * Sufficient knowledge of German * No cannabis inhalation or nicotine consumption on study day * No alcohol consumption within the last 24 h Exclusion Criteria: * Participation in a trial with investigational drugs within 30 days * Current or previous major psychiatric disorder (e.g., major depression, schizophrenia spectrum disorder) * Pregnancy or breastfeeding * Intake of CYP2C9, CYP2C19, and CYP3A4-inducers in the last 4 weeks before the study visit, e.g. rifampicin (antibiotic), carbamazepine (anticonvulsant), phenobarbital (anticonvulsant), phenytoin (anticonvulsant) or inhibitors, such as amiodarone (class III antiarrhythmic medication), antifungal drugs such as fluconazole, miconazole, voriconazole and itraconazole, antibiotics such as clarithromycin and sulfamethoxazole, ritonavir (protease inhibitor) and grapefruit juice. * The following conditions: vasopressin deficiency, pituitary tumor, active malignancy, severe hyponatremia requiring treatment, congestive heart failure, liver cirrhosis.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Quantification of phytochemicals in cannabis sativa (e.g. cannabinoids and flavonoids) and their metabolites in human whole blood samples.

Timeframe: 24 months

Trial details

NCT IDNCT06975020

SponsorUniversity of Basel

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-12-31

Contact for this trial

Urs Duthaler, PhD

+41612673889 canbiome-studie@unibas.ch

View on ClinicalTrials.gov More Driving Under the Influence of Cannabis trials