 Understanding an aggressive episode is clearly complicated by the need to numerically quantify it. Being a low frequency behavior, aggression presents a challenge to the systematic assessment required in a research study. We will employ the Childrens Aggression Scale, Parent CAS-P and Teacher CAS-T versions Halperin et al., 2002 to measure retrospectively the frequency and severity of four categories of aggression: 1 verbal aggression, 2 aggression against objects and animals, 3 provoked physical aggression, and 4 initiated physical aggression. Responders complete a Likert scale to evaluate the frequency of an act. A distinction is made between aggressive acts directed toward persons who live in the home and those who do not, and also between acts directed toward peers and those directed towards adults. The frequency of aggressive events is multiplied by its designated severity weight factor and then summed to yield a total score. We modified the instrument so that only the occurrence of impulsive aggressive events over the previous one-week period is rated see Appendix. These event types of variables fall in the category of impulsive aggression as defined above. Parentsguardians and teachers will be the respondents for this scale. 