Smaller hippocampal volumes are a consistent finding among adults with schizophrenia; it remains unknown if these changes are due to chronic psychotic illness or if they are a vulnerability factor for psychosis. We hypothesized that early psychotic symptoms would be associated with smaller hippocampal volumes in adolescents from the ABCD Study.
We tested for a correlation between hippocampal volumes using Freesurfer Hippocampal Subfield Segmentation and psychotic symptoms measured by the Prodromal Questionnaire-Brief Child Version (PQ-BC). Linear mixed models were used to test for distress score. We then ran linear mixed models looking at hippocampus volumes as a predictor for total PQ-BC score. All analyses were adjusted for age, sex, intracranial volume (ICV), rating (fixed), as well as site, scanner, and family ID (random).
10,076 sMRI scans cleared our QC criteria and were used for analyses. Smaller left hippocampus volumes were a significant predictor of PQ-BC scores (standardized beta=-0.041, p=.0034). Right hippocampal volumes were not a significant predictor of PQ-BC scores (standardized beta=-0.022, p=.118).
Smaller left hippocampus volume predicted more psychotic symptoms in children as young as nine years. However, it remains unknown if these predict the onset of future psychosis and if there are gender differences.