Physiological correlates of conduct problems and anxiety in hyperactive and learning-disabled children.

Thirty-six learning disabled children (21 of whom were also classified as hyperactive) were subgrouped according to teacher ratings of tension-anxiety and conduct problems and then compared on measures of tonic and phasic autonomic arousal. The results indicated that children rated high on the conduct problem dimension evidenced smaller amplitude specific skin conductance responses, and that anxiety appeared to exert a moderating effect on physiological responses. When the hyperactive sample was considered separately, lower skin conductance levels were observed in children rated high on conduct problems than in hyperactive children rated low in conduct problems. These findings support the notion that hyperactive and learning-disabled children are heterogeneous at a physiological level and suggest that physiological differences previously attributed to hyperactivity may actually be correlates of the conduct problem dimension.