140 adolescent in-patients were rated on a 40-item, 3-point behaviour scale. A principal component analysis was made and two major factors emerged which accounted for 44.3% of the total variance: one factor related to level of functioning and overinhibition and the other to aggression. A graphical representation of the patients with respect to the above factors provided important information as regards prognosis and clinical diagnosis. As in previous related studies (Klein & Davis (1969)), the validity of clinical diagnostic categories was confirmed and information on the process of making these diagnoses was provided