Background: Previous literature suggests that hippocampal volume reductions in schizophrenia may occur either during adolescence or at the point of transition to overt psychosis. The authors tested these hypotheses by examining the hippocampal formation in adolescents with recent onset schizophrenia.
Methods: We compared the volumes of the left and right hippocampus, obtained using stereologic methods from magnetic resonance brain images, from 40 adolescents with recent onset schizophrenia to those of an equal number of matched healthy control subjects. Symptoms were rated using the Positive and Negative Syndrome Scale.
Results: Compared with control subjects, adolescents with schizophrenia had reduced whole brain volume. After adjusting for brain volume, no group differences were observed in hippocampal volume. Duration of illness was negatively correlated with the volume of the left hippocampus. We found no effect of pregnancy and birth complications or family history of psychosis on hippocampal volumes. There was a negative correlation between severity of psychopathology and hippocampal volumes, which was significant for negative symptoms.
Conclusions: Specific hippocampal volume reductions in early onset schizophrenia do not seem to predate the onset of or to occur at the point of transition to psychosis but may develop in adolescence during the early stages of the illness.