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NCT Number: NCT06975020

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

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.

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Key information

Conditions

Driving Under the Influence of Cannabis Chemically-Induced Disorders Marijuana Abuse Mental Disorders Substance-Related Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Insitute of forensic medicine

Basel, 4056, Switzerland

Location status: Recruiting

Location contact

Urs Philipp Duthaler, PhD

CONTACT

[email protected]

+41612673889

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Participants will prepare their cannabis product ad libitum and inhale the prepared product as usual for a maximum of 15 minutes.

Drug

Participants will prepare and inhale their cannabis product ad libitum for a maximum of 15 minutes. Prior to inhaling cannabis (the baseline), and for three hours thereafter, biological samples (e.g., blood) will be collected. Participants will be asked to complete a series of questionnaires addressing their (subjective) neurocognitive function and well-being, as well as their self-rated driving ability and subjective cannabis effects.

Primary outcomes

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

    Time frame: 24 months

    Quantification of the blood concentration of cannabis sativa phytochemicals such as minor cannabinoids, cannabinoids, and flavonoids. Blood samples will be analyzed at baseline and several time-points (0, 10, 20, 60, 180) post consumption of cannabis. Concentrations will be reported as ng/mL whole blood.

Secondary outcomes

  1. Measurement of the expression levels of relevant genes e.g. cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) in whole blood samples by e.g. RT-PCR to evaluate especially their correlation with cannabinoid plasma levels, metabolism, and ph

    Time frame: 24 months

  2. Assessment of selected genetic polymorphisms in the genes known to interact with cannabinoids (i.e. CYP2C9, CYP2C19) by e.g. RT-PCR to evaluate their influence on cannabinoid plasma levels and the ability to predict cannabinoid metabolism and pharmaco

    Time frame: 24 months

  3. Quantitation of biomarkers applicable to determine the activity of enzymes or transporters known to be involved in the handling of cannabinoids (e.g. 4-ß-hydroxycholesterol, Coproporphyrin I und Coproporphyrin III)

    Time frame: 24 months

  4. Comparison of DNA methylation profiles on blood-derived DNA samples between regular and non-cannabis users by evaluating key CpG sites (e.g., in the MCU gene) that interplay with risk factors and mental health by e.g. targeted Illumina DNA methylation

    Time frame: 24 months

  5. Analysis of the protein-bound and free fractions of the different cannabinoids and their metabolites using e.g. equilibrium dialysis or ultracentrifugation

    Time frame: 24 months

  6. Targeted and untargeted analysis of endogenous biomarkers (e.g. endocannabinoids) using e.g. high-resolution mass-spectrometry

    Time frame: 24 months

  7. Subjectively experienced effects of cannabis inhalation (e.g. subjective driving ability, psychological effects and well-being) assessed by questionnaires (e.g. VAS)

    Time frame: 24 months

  8. The effects of cannabis inhalation on neurocognition by non-invasive, neurocognitive testing

    Time frame: 24 months

  9. Self-reported mood as measured e.g. by the Bf-SR questionnaire.

    Time frame: 24 months

  10. Usual reasons for cannabis use as measured e.g. by the Marijuana Motives Questionnaire (MMQ)

    Time frame: 24 months

  11. Measurement of hormones and biomarkers involved in the regulation of fluid balance (e.g. plasma osmolality …)

    Time frame: 24 months

  12. Measurement of hormones and biomarkers of the anterior and posterior pituitary gland (e.g., plasma oxytocin, neurophysin I, ACTH, TSH, prolactin …)

    Time frame: 24 months

Study contacts

Contact information is provided by the study sponsor or research team.

Urs Duthaler, PhD

CONTACT

[email protected]

+41612673889

Sponsors and collaborators

Lead sponsor

University of Basel

Other

Collaborators

  • Biopharmacy, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
  • Department of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland
  • Institute of Forensic Medicine, University of Basel, Basel, Switzerland
  • University Psychiatric Clinics Basel

Registry information

Official study title

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

Acronym: CANBiome

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
May 16, 2025
Registry last updated
Dec 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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