[Sequelae of cannabis use--results of a survey of experts on traffic accidents and "echopsychoses" (flash-back)].

There is a lack of knowledge in the judgement of the effects and the dangerousness of cannabis. Specially in the judgement of the delinquency of traffic the effects must be clarified. Cannabis plays often a fundamental role in road accidents. Obviously flash-backs of consumers of cannabis are observed more often than documented in the literature hitherto. The existing but not published experiences of experts have to be considered extensively to get an idea more complete of the diverse effects of cannabis in traffic offences.