The relationship of neuropsychological impairment to conduct disorder in adolescence: A conceptual review

This review is an attempt to expand the understanding of the neuropsycholog ical mechanisms that may influence the expression of violent or aggressive behavior in adolescents. Although a relative large literature of adult stud ies examining the relation of neuropsychological impairment and aggression exists, the research literature investigating this relationship in adolesce nts is much smaller. With a few exceptions, the delinquent literature suffe rs from methodological problems, including biased sampling methods, small n umbers of subjects, failing to objectively diagnose conduct disorder, incor rect use of specific statistical procedures, and lacking of appropriate con trol groups. In general, a mixed pattern of neuropsychological deficits are displayed across studies, depending on the sampling method, methodological design, statistics employed, control groups, and assessment tools that wer e utilized. Verbal deficits have been frequently displayed across the liter ature, while evidence for executive dysfunction varies, depending on the sp ecific construct being evaluated (e.g, attention, cognitive flexibility, co ncept formation, planning abilities) and the specific population. Relativel y inconsistent findings have been observed for visuospatial, sensory, and m otor deficits. This article provides a critical review of this literature a nd discusses the varying impact that any neurological insult will have,depe nding on premorbid personality and cognitive functioning, location of the l esion, age at which the injury occurred, child's pre- and postinjury enviro nment, and ability of the brain to adapt to acquired deficits as the result of the insult. On the basis of this review and neuropsychological theory, four subgroups within this population are proposed (i.e., adolescents with subcortical injuries, dominant hemisphere temporal-parietal injuries, nondo minant hemisphere temporal-parietal injuries, and injuries to the prefronta l regions), which may better explain the neuropsychological and behavioral outcomes exhibited by this heterogeneous population. Recommendations for fu ture research are offered. (C) 2000 Elsevier Science Ltd. All rights reserv ed.