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Weed or wheel! FMRI, behavioural, and toxicological investigations of how cannabis smoking affects skills necessary for driving

  • Battistella, Giovanni Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), and University of Lausanne, Lausanne, Switzerland
  • Fornari, Eleonora Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), and University of Lausanne, Lausanne, Switzerland - CIBM (Centre d’Imagerie Biomédicale), Centre Hospitalier Universitaire Vaudois (CHUV) unit, Lausanne, Switzerland
  • Thomas, Aurélien CURML (University Center of Legal Medicine), UTCF (Forensic Toxicology and Chemistry Unit), Geneva, Switzerland
  • Mall, Jean-Frédéric Department of Psychiatry, SUPAA (Service Universitaire de Psychiatrie de l’Age Avancé), Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
  • Chtioui, Haithem Department of Clinical Pharmacology and Toxicology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
  • Appenzeller, Monique Department of Clinical Pharmacology and Toxicology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
  • Annoni, Jean-Marie Neurology Unit, Department of Medicine, University of Fribourg, Fribourg, Switzerland
  • Favrat, Bernard CURML (University Center of Legal Medicine), UMPT (Unit of Psychology and Traffic Medicine), Lausanne and Geneva, Switzerland
  • Maeder, Philippe Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), and University of Lausanne, Lausanne, Switzerland
  • Giroud, Christian CURML (University Center of Legal Medicine), UTCF (Forensic Toxicology and Chemistry Unit), Lausanne, Switzerland
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    02.01.2013
Published in:
  • PLoS ONE. - 2013, vol. 8, no. 1, p. e52545
English Marijuana is the most widely used illicit drug, however its effects on cognitive functions underling safe driving remain mostly unexplored. Our goal was to evaluate the impact of cannabis on the driving ability of occasional smokers, by investigating changes in the brain network involved in a tracking task. The subject characteristics, the percentage of Δ9-Tetrahydrocannabinol in the joint, and the inhaled dose were in accordance with real-life conditions. Thirty-one male volunteers were enrolled in this study that includes clinical and toxicological aspects together with functional magnetic resonance imaging of the brain and measurements of psychomotor skills. The fMRI paradigm was based on a visuo-motor tracking task, alternating active tracking blocks with passive tracking viewing and rest condition. We show that cannabis smoking, even at low Δ9-Tetrahydrocannabinol blood concentrations, decreases psychomotor skills and alters the activity of the brain networks involved in cognition. The relative decrease of Blood Oxygen Level Dependent response (BOLD) after cannabis smoking in the anterior insula, dorsomedial thalamus, and striatum compared to placebo smoking suggests an alteration of the network involved in saliency detection. In addition, the decrease of BOLD response in the right superior parietal cortex and in the dorsolateral prefrontal cortex indicates the involvement of the Control Executive network known to operate once the saliencies are identified. Furthermore, cannabis increases activity in the rostral anterior cingulate cortex and ventromedial prefrontal cortices, suggesting an increase in self-oriented mental activity. Subjects are more attracted by intrapersonal stimuli (“self”) and fail to attend to task performance, leading to an insufficient allocation of task-oriented resources and to sub-optimal performance. These effects correlate with the subjective feeling of confusion rather than with the blood level of Δ9-Tetrahydrocannabinol. These findings bolster the zero-tolerance policy adopted in several countries that prohibits the presence of any amount of drugs in blood while driving.
Faculty
Faculté des sciences et de médecine
Department
Médecine 3ème année
Language
  • English
Classification
Biological sciences
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/302925
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