Progressive cortical gray matter loss in adolescence is specific to schizophrenia

196

13. Neuroimaging, Structural

IN VIVO VISUALIZATION CALLOSUM

OF CORPUS

ABNORMALITIES

IN

SCHIZOPHRENIA V. M. Goghm'i,* D. J. Lang, L. C. Kopala, R. A. Vandorpe, Q. Rui, W. G. Honer

Psychiatry, University of British Columbia, Vancouvet, BC, Canada Neuropsychological and neurophysiological studies provide evidence for abnormal inter-hemispheric communication in schizophrenia. These abnormalities may have a substrate in structural irregularities of the corpus callosum (CC). We previously reported CC structural differences in chronic schizophrenia (Goghari et al., 2002, Schiz Res, 53: 100). This study attempted to expand and replicate those findings by investigating first-episode psychosis and a new sample of chronic patients. CC measurements were acquired from one T2-weighted mid-sagittal slice (5ram thickness) for first-episode psychosis (n=35), chronically medicated schizophrenia (n=21), and healthy comparison subjects (n=24). Global and regional areas were measured. Four sub-regions were roughly matched to fiber pathways from functionally related cortical regions. An ANCOVA revealed no significant differences for the total or sub-regions of the CC between the three groups, when covarying for age, gender, and intracranial volume. Patients with chronically medicated schizophrenia had smaller total CC area (F(1, 40)=5.27, p=0.03), anterior region (F(1, 40)=5.56, p=0.02), and motor region (F(1, 40)=6.84, p=0.01) than healthy comparison subjects. These findings suggest that structural abnormalities of the CC exist in schizophrenia and these abnormalities may be global, with some specific regions affected more than others. Structural differences in the CC may be a substrate for interhemispheric functional dysconnectivity in schizophrenia. This research is supported by the Stanley Foundation and the Canadian Institutes of Health Research.

PROGRESSIVE

CORTICAL

LOSS IN ADOLESCENCE

GRAY MATTER IS S P E C I F I C T O

period. Results: The COS group had significantly greater gray total and regional gray matter loss than did the psychosis NOS or healthy control groups (ANOVA post hoc p values from 0.002 to 0.02). Psychosis NOS and control groups did not differ significantly from each other. Conclusions: There is a significant and diagnostically specific cortical gray matter volume loss in COS not seen in children and adolescents with atypical psychosis. Since both patient groups had similar medications, hospitalization, and cognitive functioning, this effect appears specific to schizophrenia. Either a progressive neurodevelopmental process and/or plastic brain response to schizophrenia could account for this.

A SEXUALLY

DIMORPHIC

FRONTAL TO AMYGDALA

RATIO OF ORBITAL VOLUME

IS

ALTERED IN SCHIZOPHRENIA R. C. Gur,* B. I. Turetsky, W. B. Bilker, C. Kohler, R. E. Gur

Psychiatry, University of Pennsylvania, Philadelphia, PA, USA We have recently described a sexually dimorphic distribution of orbito-frontal volume relative to amygdala volume. Specifically, healthy men had lower ratio than women. This anatomic dimorphism has been related to better modulation of aggression in women. We now report data on this ratio in 63 men and 51 women with schizophrenia compared to a sociodemographically balanced sample of 102 healthy people (43 men, 59 women). Both men and women with schizophrenia have reduced dorsal prefrontal cortex (medial and lateral), but only women with schizophrenia show reduced orbital frontal volume. By contrast, amygdala volume was reduced in men with schizophrenia compared to healthy men, and significantly increased in women with schizophrenia compared to healthy women. Thus, while men with schizophrenia show a normal ratio of orbital cortex to amygdala volume, women with schizophrenia show a reduced ratio compared to healthy women. The results may relate to greater prevalence and severity of affective symptoms in women with schizophrenia.

SCHIZOPHRENIA N. Gogtay,* A. Sporn, R. Nicolson, L. Classen, D. Greenstein, J. N. Giedd, P. Gochman, M. Lenane, A. Evans, J. L. Rapoport

Child Psychiatry Branch, NIMH, Bethesda, MD, USA Background: Recent anatomic brain MRI studies show post-psychotic progressive loss of cortical gray matter in schizophrenia (COS), which is most striking for adolescent populations. However, the diagnostic specificity and the relationship of these changes to drug treatment and cognitive functioning remain unclear. A prospective brain MRI study of patients with childhood onset schizophrenia and pediatric patients with ?atypical psychosis? was carried out to test the hypothesis that cortical gray matter loss would occur for COS, but not for the adolescents with atypical psychoses. Methods: Brain MRI scans were obtained on 19 patients with psychotic disorder not otherwise specified (NOS)(mean age=13.3+3), age, sex, IQ, drug treatment matched COS patients (n=23,mean age=13.9+2.5), and age and sex matched healthy controls (n=38,mean age=l 3.2+3). The mean follow up period was 2.5+0.8yrs. Volumes of the cerebrum, total and regional gray matter, were obtained using an automated analysis system, and change in volume over time was calculated. One-way analyses of variance (ANOVA) with post hoc comparisons (Tukey HSD) were performed to examine group differences in the percent change in gray matter across the follow up

FRACTAL ANALYSIS OF MAGNETIC RESONANCE

IMAGES(MRI): A COMPARATIVE

STUDY OF SCHIZOPHRENIA COMPULSIVE

AND OBSESSIVE-

DISORDER

T. Ha,* U. Yoon, T. Yoon, J. M. Lee, J. S. K w o n

Psychiatry, Seoul National University Hospital, Seoul, South Korea The brain has been shown to be a fractal structure and a few studies applied nonlinear dynamic framework to the psychiatric investigation successfully. We estimated fractal dimension of magnetic resonance image(MRI) boundary between cerebral cortex and cerebrospinal fluid using box-counting method to find if selforganizing failure is involved in structural abnormalities of the brain in patients with schizophrenia and obsessive-compulsive disorder(OCD). MRI of 59 schizophrenics, 39 OCD patients, and 43 normal controls were collected and analyzed. There was no significant difference in sex ratio and age between three groups. Total brain volume of patients with schizophrenia and OCD was significantly smaller than that of normal controls(ANOVA, p=0.000), but, there was no difference between schizophrenia and OCD. Both brain hemispheres of patients with schizophrenia(ANCOVA, p=0.000) and OCD(p<0.01) showed significant decrease in fractal dimension compared with those of controls. Fractal dimension

International Congress on Schizophrenia Research 2003