Send to

Choose Destination
See comment in PubMed Commons below
Ann Pharm Fr. 2006 May;64(3):192-6.

[Cannabis and road crashes: a survey of recent French studies].

[Article in French]

Author information

Centre hospitalier universitaire de Poitiers, Service de toxicologie et pharmacocinétique, Chu, BP 577, F 86021 Poitiers Cedex.


The clarification of the mechanisms of action of cannabis and its effects on motor and cognitive functions, the results of previous studies performed on driving simulators and closed or open-road driving trials, are important criteria for highlighting the increased risk of road crashes for drivers after a recent use of cannabis. In addition epidemiological studies allow to measure the magnitude of the problem. A survey of French epidemiological studies performed from 1999 to 2004, as well as the data of THC distribution in tissues studies performed on man and animal allowed us to draw a number of conclusions. The risk of road crash after a recent use of cannabis is increased by more than 2.4 in all studies. The prevalence of cannabis use in drivers involved in a road crash has dramatically increased during the last years. For methodological reasons (a too high threshold for THC positivity, a too long time delay between accident and blood sampling), the annual number of fatal cases induced by a cannabis use was likely underestimated. This assessment is consistent with recent data which indicate that THC could be still present in brain while absent in blood. A positivity threshold for THC in blood of 0.5 ng/mL would be more appropriated. So, all recent French studies highlighted that a recent use of cannabis impairs driving ability and that it would be advisable to intensify roadside testing for drugs of abuse.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Masson (France)
    Loading ...
    Support Center