By a double-blind test 54 volunteers were tested for their car driving capacity before and after taking tetrahydrocannabinol (THC) at doses of 350, 400 or 450 ug/kg and a placebo. Medical examination of those in the THC group revealed injected conjunctival vessels, increased pain sensitivity as well as significant pulse rate increase and a rise in diastolic blood pressure. Three effects were especially prominent in the self-assessment of the THC group:-(1) A definite inward turning followed by an impairment of attention and concentration capacities; (2) change in motor functions, co-ordination and associations; (3) resulting from a discrete alienation experience, an impaired coming to terms with the environmental situation. These self-assessments agreed with the results of experimental studies of a number of variables in driving and personality features. The study demonstrates that THC, because of its inhibiting as well as stimulating effects, influences psychological and physiological functions important for driving in a manner different from alcohol. It changes and worsens adaptability as well as the mentioned aspects of driving behavior especially if there is simultaneous stress. At times when rapid decisions and actions are required, prolongation of reaction time and an increased frequency of wrong and inadequate responses were observed. The smooth automatism, which is so important in car driving, was disturbed. The degree of impairment depended on the initial personality structure and individual effects of the drug on basic mood and attitude. The intensity of action of THC was still measurable five to six hours after intake. The subjects still noticed a definite effect eight to ten hours after intake, and discrete late effect as long as 24 hours later. /Author/

  • Corporate Authors:

    Thieme (Georg) Verlag

    Herdweg 63, Postfach 732
    Stuttgart N,   Germany 
  • Authors:
    • Kielholz, P
    • Goldberg, L
    • HOBI, V
    • LADEWIG, D
  • Publication Date: 1972-5

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00099575
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Files: TRIS
  • Created Date: Nov 5 1975 12:00AM