Shortening of the hippocampal formation in first-episode schizophrenic patients.

Shortening of hippocampal formation (HF) in chronic schizophrenic patients have been demonstrated in our previous study. The purpose of the present study is to test if shortening of the HF occurs in schizophrenic patients suffering their initial psychotic episode. We performed contiguous, 1 mm thick, magnetic resonance imaging scans in 20 first-episode schizophrenic patients, 21 chronic schizophrenic patients, and 25 healthy subjects. Both groups of schizophrenic patients demonstrated significant shortening of the HF compared with normal controls (first-episode schizophrenia, 5.3%; chronic schizophrenia, 8.0%). However, the HF length was not significantly different between the first-episode and chronic schizophrenic patients. No significant correlation was seen between the HF length and the duration of illness in chronic schizophrenic patients. These results suggest that the HF shortening observed in schizophrenic patients may be genetic and/or developmental in origin.