Direct evidence concerning the role of amphetamines in highway accidents is scant. Laboratory data indicate that most of the basic skills involved in driving are not adversely affected by amphetamine dosages within the normal clinical range, and may in fact be slightly enhanced. Such enhancement is generally greater in sleep-deprived subjects, but is not limited to states of sleep deprivation. Enhancement has also been reported in subjects whose skills have been degraded by alcohol, although results have not been consistent across performance measures. Although there is some evidence that amphetamines induce overconfidence or increase risk acceptance, the effects reported have been neither so strong nor so consistent as to justify much of the apparent concern. Excessive or prolonged "spree" use is widely recognized to result in abnormal psychological states that are incompatible with safe driving performance, and known amphetamine abusers have been found to be involved in disproportionate numbers of highway accidents. Available epidemiological statistics are inadequate to establish how often such excessive consumption is associated with driving, or in any other way to quantify the total contribution of amphetamine abuse to traffic accidents.
Abstract