Signal Detection and Chlorpromazine

Abstract

Nine normal subjects were tested on an auditory signal detection task under six signal-to-noise conditions while under the influence of different dosages of chlorpromazine, a commonly used major tranquilizer. A significant subject-x-drug-dosage-level interaction was found, some subjects showing impairment of signal detection performance while on medication while others did not show such impairment. Reasons for individual differences in response to the drug require further investigation. All subjects adopted increasingly conservative decision-making criteria and under-responded more as the signal-to-noise conditions became more difficult. It was suggested that chlorpromazine is likely to cause a greater deficit in signal detection performance in a continuous vigilance task than in a task where periodic brief focusing of attention is required and an alerting cue is provided immediately preceding the possible occurrence of a signal.