Cavum septum pellucidum in subjects at ultra-high risk for psychosis: compared with first-degree relatives of patients with schizophrenia and healthy volunteers.

OBJECTIVE: The cavum septum pellucidum (CSP) is a space between the two leaflets of the septum pellucidum, and is a putative marker of disturbance in early brain development. We examined whether CSP was present more frequently in subjects at ultra-high risk (UHR) for psychosis compared to first-degree relatives of patients with schizophrenia (genetic high risk, GHR) and healthy controls (HC).
METHODS: We evaluated CSP in 87 subjects (30 UHR, 23 GHR, and 34 HC) according to a published grading system using high-resolution magnetic resonance imaging (MRI) with 0.45-mm slice thickness. We also assessed two other criteria: presence of CSP on at least one MRI slice, and abnormally large CSP (i.e., > or =6 mm in length). Correlational analysis between CSP measures and clinical symptoms was also examined.
RESULTS: Based on the grading scale, the UHR group exhibited a significantly higher incidence of abnormal CSP (grades 2, 3, and 4) compared to the HC group, but there were no significant differences in the incidence of abnormal CSP between the UHR and GHR or the GHR and HC groups. There were no significant differences among the groups in the presence of CSP on at least one MRI slice or abnormally large CSP based on the length of CSP. In addition, no significant correlations between CSP measures and clinical symptoms were found.
CONCLUSION: These findings suggest that abnormal CSP might be associated with susceptibility to psychosis, although the CSP itself might be a normal anatomical variant. Further studies using a larger sample are needed to clarify issues on neurodevelopmental perspective in subjects at high risk for psychosis.