Do early onset conduct disordered adolescents perform like brain injured or normal adolescents on cognitive tests?

In order to better understand whether adolescents with early onset conduct disorder are predisposed to this disorder because of neurological problems, the present study compared the performance of early onset conduct disordered adolescents to adolescents with left hemisphere and right hemisphere brain injuries and normal controls. It was hypothesized that adolescents with early onset conduct disorder would perform similar to adolescents with left hemisphere injury, confirming theories that neurological dysfunction may predispose children to the development of conduct disorder. Fifteen adolescents with conduct disorder were compared on a battery of cognitive tests to 12 left hemisphere brain injured, 11 right hemisphere brain injured, and 15 normal middle school adolescents. F-tests indicated that there were significant differences among the four groups on all measures (p < .01). According to a series of t-tests on each of the nine cognitive measures, there were no differences found between the early onset conduct disordered subjects and the left hemisphere subjects. The early onset conduct disordered group performed worse than the right hemisphere group on 7 of the 9 comparisons, and worse than the normals on 9 of 9 comparisons. The normal group performed better than all three of the other groups. These results demonstrate that the pattern of neuropsychological performance by early onset conduct disordered adolescents was similar to that of left hemisphere injured adolescents and different from that of the right hemisphere injured and normal adolescents. Potential applications of this research include describing new approaches to treatment of this disorder based on their similarity with the left hemisphere brain injured group.