COMPUTERISED TOMOGRAPHIC BRAIN SCAN FINDINGS IN A COHORT OF NIGERIANS WITH SCHIZOPHRENIA AND MANIA

Abstract

Computerised tomographic (CT) scan has become a useful and reliable non-invasive tool for investigating possible neuropathological conditions associated with psychiatric disorders. While earlier studies of the so called functional psychotic states focused on schizophrenia, some studies of affective disorder have shown that the findings may not be specific to schizophrenia. These studies have been carried out in the developed countries where schizophrenia is predominantly characterised by insidiuos onset and poor outcome (Type II). The need to replicate these findings in a developing country where schizophrenia is thought to be predominantly of acute/onset and relatively good outcome, has necessitated this study. With their consent, and those of their relations, the CT scan of 50 schizophrenic, 14 manic (in steady state) and 41 normal subjects, were compared. Clinical assessments were done independently of CT measures. The following CT measurements were done: the Bicaudate Ratio; the lateral ventricular - Brain Ratio; the Sylvian Fissure Area Ratio; densities of the Frontal and parietal areas; and visual ratings of Cortical Sulci and central (Subcortical) atrophy. Analysis of variance showed that across the groups, significant difference between the patients and normal subjects were noted for Sylvian Fissure Area. The Third Ventricle area of schizophrenics was significantly larger than that of normal subjects, while being closer to that of manic subjects. The tendency for patients to have larger lateral ventricle area than normal subjects just failed to reach acceptable significance ( 0.05). Schizophrenics with negative symptoms

had significantly larger mean lateral ventricle area than normal subjects; those with poor outcome as well as those without negative symptoms had significantly larger mean third ventricle area and Sylvian Fissure area than normal subjects. Two-way ANOVA showed no significant interaction between outcome and negative symptoms. In multiple regression analysis, lateral ventricle area could be significantly predicted among schizophrenics by bicaudate ratio and third ventricle area, but not among manic subjects. Psychiatric patients had significantly higher prevalence of cortical sulci and subcortical atrophy; and higher mean frontal density than normal; while schzophrenics had significantly higher parietal density than other groups. CT measures did not significantly correlate with duration of illness. In analysis of co-variance, these findings were sustained. The findings are similar to those from developed countries in showing that the so called functional psychotic illness are most probably associated with non-specific neuropathology. The findings are discussed in the light of evidence from neuropathological studies, neuropsychological theories and Crow's hypothesis.