This paper addresses the neuropsychological evaluation of impulsive aggression in emotionally disturbed students. Specific complications of organic aggressive syndrome include its unpredictable nature and basis in organic etiology. Characteristically, there is a sudden onset of unprovoked rage and violence accompanied by a drastic change in affect. The most significant functional disorder, post-traumatic stress disorder, is often associated with head injury and increasingly seen as a primary source of substance abuse in adolescents. Determining the site of organic brain damage may require sophisticated medical technology and examination of the role of neurotransmitters. Distinguishing between an organic disorder and such functional disorders as post-traumatic stress disorder and substance intoxication can be difficult. Functional disorders are significantly more amenable to successful treatment than are organic disorders. Criteria of the Diagnostic and Statistical Manual III--Revised for these various conditions are detailed. Also described is the Overt Aggression Scale which allows teachers, parents, and clinicians to provide a quick objective rating of verbal and physical aggression. Includes 33 references. (DB)