Reliability and validity of alcohol-induced heart rate increase as a measure of sensitivity to the stimulant properties of alcohol

Rationale: Alcohol-induced heart rate (HR) stimulation during the rising li mb of the blood alcohol curve reliably discriminates between individuals at differential risk for alcoholism, and appears to be a potential psychophys iological index of psychomotor stimulation from alcohol. Objectives: Three studies are presented which explore the reliability and convergent and disc riminant validity of this alcohol response index. Methods: Young men with a nd without a multigenerational family history of alcoholism were administer ed a 1.0 ml/kg dose of 95% USP alcohol. Resting baseline cardiac and subjec tive measures were assessed before and after alcohol consumption. Results: Study 1 demonstrated that alcohol-induced HR stimulation was significantly and positively related to alcohol-induced changes in mood. Study 2 demonstr ated that alcohol-induced HR stimulation was reliable across two alcohol ad ministration sessions (r=0.33-0.66, P <0.01). Study 3 explored the relation ship between the proposed index and measures of sensitivity to alcohol prev iously linked to genetic predisposition to alcoholism. Multiple regression analysis indicated that alcohol-induced HR increase and reduced subjective intoxication (measured using the Subjective High Assessment Scale) were bot h positively associated with alcohol-induced changes in mood states that ha ve previously been shown to be sensitive to the effects of stimulant drugs and the reinforcing effects of alcohol. Conclusions: Sensitivity to alcohol -induced heart-rate stimulation during the ascending limb of the blood alco hol curve may be a useful and informative marker for understanding suscepti bility to alcoholism.