Signs and symptoms predictive of drug impairment Academic Article uri icon


  • A double blind study was performed to evaluate the ability of police officers to detect drug impairments and to identify the type of drug responsible for the impairment, on the basis of observed symptoms and psychophysical measurements of performance. The officers were not allowed to interview the subjects. Results showed that even with this partial information the officers are able to detect drug impairment at better-than-chance levels, but the association between drug ingestion and identification of the specific impairing drug was not very high. Drug identification was best for alprazolam impairment, noticeably poorer for cannabis and codeine impairment, and no better than chance for amphetamine impairment. To improve identification, the officers should always list the two most probable impairing drugs (rather than one), and be more consistent in their use of observed signs and …

publication date

  • May 22, 2000