[Comparative regions of interest study in schizophrenia, panic disorder and its comorbidity: the relationship between hippocampal volume and positive psychotic symptoms].

INTRODUCTION

Schizophrenia and panic disorder have been associated with limbic alterations, such as reduced volumes of the hippocampus and amygdala. However, there are conflicting results and a lack of previous neuroimaging studies assessing the implication of these structures when the two diagnosis are comorbid. AIM. To determine the type and magnitude of volumetric limbic alterations in schizophrenia, panic disorder and their comorbidity.

SUBJECTS AND

METHODS

We measured the volume of the amygdala and hippocampus using a manual regions of interest segmentation method in schizophrenic patients (group 1), panic disorder (group 2), those who present comorbidity of the two diagnosis (group 3), and a control group of healthy subjects (group 4).

RESULTS

Patients included in groups 1 and 3 have significantly lower volume of left hippocampus than control group. In these groups, we did find that the volume of the left hippocampus was positively associated with positive symptoms' severity. We did not find volumetric differences in the amygdala between the groups.

CONCLUSIONS

Our results confirm a decreased volume of the left hippocampus in schizophrenia. The association between the severity of positive psychotic symptoms (delusions and hallucinations) and hippocampus volume could be mediated by the propensity to develop a fear conditioned response to neutral stimuli in subjects with higher hippocampal volumes.