Cardiac responsivity in individuals at high risk for alcoholism.

Heart rate was recorded from male siblings over the age of 30 who were members or either alcoholic or control families. Brothers from alcoholic families included both those with a diagnosis of alcoholism (n = 66) and those without such a diagnosis (n = 18). Control brothers (n = 33) were chosen for absences of any Axis I psychopathology including alcoholism in all first- and second-degree relatives. Subjects were engaged in two auditory tasks. All subjects were presented with high- and low-pitched tones with varying probabilities. In the first task (counting), subjects were told to count only the number of high tones. In the second task (choice reaction), subjects were asked to perform a simple motor response to each high or low tone. Prestimulus levels, anticipatory deceleration and acceleration were compared between the three groups. All members of the affected families, whether alcoholic themselves or not, were found to have a significantly higher baseline heart rate than members of control families. In addition, differences in the anticipatory deceleration were greater in control brothers than in brothers from the affected families for the counting task.