Dr G.B. Chesher
Department of Pharmacology University of Sydney and National Drug and
Alcohol Research Centre University of New South Wales.
7. ALCOHOL AND CANNABIS IN EPIDEMIOLOGICAL STUDIES
|The relative risk for drivers with alcohol plus cannabis was also greater
than that for the control group, but this culpability ratio was no different from the
alcohol only group. Also in this study (as indicated above), there was no significant
difference in the BAC of the alcohol-only drivers and those with alcohol plus cannabis.
|The same finding was reported by Terhune who also suggested that the high
levels of alcohol are primarily responsible for the increased crash risk.
|Therefore the effects of alcohol in road crashes are really profound. The
studies reviewed here using the method of 'responsibility analysis' have confirmed the
information already established by the case-control methods-that alcohol is the dominant
drug associated with risky and dangerous driving and road crashes.
|There have been suggestions throughout the studies reviewed here that the
crash responsibility rates associated with the low BAC plus other drug, might be higher
than in the low alcohol-only groups. The interaction of other drugs and alcohol (including
cannabis) require further study using epidemiological techniques. One must remember the
description by Perez-Reyes of the effect of the order of administration of alcohol and
cannabis in these interaction studies.