Comparison of the Effects of Ketamine and Morphine on the Performance of Representative Military Tasks

摘要

This study evaluated the effects of 25 mg of intramuscular (IM) ketamine versus 10 mg of IM morphine versus saline placebo on the performance of representative Warrior Skill Tasks in 48 healthy subjects. Ketamine demonstrated rapid onset of action and hemodynamic stability but did not result in improved Soldier performance. Overall, subjects reported more symptoms associated with ketamine versus morphine and placebo, chiefly among them dizziness, poor concentration, and feelings of happiness. Performance decrements on ketamine, when present, manifested as slower performance times rather than procedural errors. This may represent the adoption of a cautious posture suggested by risk propensity testing whereby the subject is aware of his or her impairment, trading speed for preservation of task accuracy. Despite the fact that subjects were more symptomatic on ketamine, the Warrior Skill Tasks were largely resistant to performance decrements, suggesting that a trained task skill (autonomous phase) remains somewhat resilient to the drugged state at this dosage.