Estimation of time and the subclassification of schizophrenic disorders.

Estimation of short time intervals by 60 healthy subjects, 50 patients with schizophrenic disorders, and 8 with schizotypal personality disorders, was investigated using the three different methods, adjusting a metronome, verbal estimation, and operative estimation (production). The schizophrenic patients tended to over-estimate time with all three methods. Overestimation was also found when longer intervals were studied. Patients with different types of schizophrenic disorders, classified according to DSM-III criteria, over-estimated time about the same; no significant differences were found. Different courses of schizophrenia were also studied. Patients in remission over-estimated time to the same extent as chronic patients; the subchronic patients probably over-estimated less. Schizotypal personality disorders did not seem to be associated with a tendency to over-estimate short time intervals. The results were discussed in the context of perceptual disturbances in schizophrenic disorders.