An exploratory study of structured and unstructured play was conducted with a small number of severely disturbed and normal children 9 to 13 years of age. Specifically, the investigators characterized psychopathology from a cognitive-developmental perspective by focusing on the Piagetian "scheme" and its manifestation in the play and classification tasks of public school students and those in a day treatment institution. The study resulted in a preliminary list of criteria differentiating disturbed and normal subgroups. Case studies illustrated differences between the two populations in scheme intercoordination, repetition, modifiability, assimilation and accommodation, and symbolic nature. (Explanations of scheme deviations are presented through examination of problems in subject/object interactions, and clinical applications of Piagetian theory are discussed.) (RH)