The subclinical characteristics of schizophrenic children have not been sufficiently investigated to present specific evidences. To elucidate the picture of them, and to find out indicators which predict later development of schizophrenia, childhood behaviors of the adult schizophrenia subjects were investigated in a questionnaire-based retrospective study.

Schizophrenia outpatients (n = 30) in his/her twenties and normal healthy subjects (n = 200) were investigated. All patients are diagnosed according to DSM-IV-TR as schizophrenia, and who present now mainly negative symptoms after passing an acute stage. By modified use of the CBCL (Child Behavior Checklist) as a retrospective assessment questionnaire, the parents of the patients and of control subjects rated their childhood behavior.

The hit-rate when classifying the schizophrenic and normal subjects by discriminant function using the syndrome scales of CBCL totaled 89,0%. Notable in an item-level analysis was an extremely attenuated aggression in personal relations in the schizophrenia subjects. Among eight subscales of the CBCL, those of Withdrawal, Social Problems, Attention Problems and Aggressive Behavior contributed most to the accuracy of the prediction of group membership.

The results suggest that subclinical behavioral and psychological characteristics of schizophrenia already exist in the patients' childhood. The quite early detection of schizophrenic children seems possible.