Instrumental analysis of ethanol-induced intoxication in human males

A study was conducted to assess subjective reports of intoxication during the ascending phase of the plasma ethanol curve. Eighteen male social drinkers were divided into three groups and were given either placebo, 0.347 g/kg ethanol or 0.694 g/kg ethanol under double-blind conditions. Subjects reported levels of intoxication both instrumentally, by moving a joystick device, and verbally using an 11-point self-rating scale. Compared to placebo, ethanol produced significantly higher verbal self-rating scores, but there were no differences in the scores between the low- and high-dose ethanol groups. Instrumental responses of ethanol effects did, however, distinguish between the two ethanol treatments. All subjects who received ethanol reliably detected its effects when plasma ethanol levels reached 32 mg/dl, but only the subjects who received the high dose reported episodes of intense well-being or euphoria. Ethanol-induced euphoria occurred while plasma ethanol levels were rapidly rising, and was characterized by multiple, paroxysmal episodes that typically lasted about 3 min each. This study demonstrated that a continuously available instrumental response provided sensitive and reliable measures of rapidly changing behavioral states associated with ethanol-induced intoxication.