Comparison of Cognitive Patterns in Treatment-naive Schizophrenia and First-episode Bipolar Affective Disorder

Abstract

Abstract Introduction: Neurobiological understanding of schizophrenia and bipolar disorder has revealed presence of structural brain changes in areas of brain controlling cognition. These cognitive deficits have been hypothesized to have been present as endophenotype which further deteriorate and precipitate mood episode and psychotic episode. The presence of these deficits early in the course of illness only supports the hypothesis. The study was conducted with the aim to describe the cognitive pattern in patients with treatment naiive schizophrenia and first episode bipolar affective disorder and to study the correlation between the deficits and severity of disorder. Methodology: The study was conducted in a zonal service hospital wherein successive patients of BPAD and schizophrenia, between the age group of 20-45 years, studied at least up to class 5, with no evidence of past psychiatric or neurological illness or other physical comorbidity were included in the study. Age and sex matched unrelated controls were selected from the general population. The groups where administered PGI memory scale, Bhatia’s short battery of performance test for adults and Verbal assessment of intelligence scale for adults (VAIS) by the clinical psychologist. Symptom severity was scored on PANSS, YMRS and HAM-D respectively. SPSS program for windows, version 17.0 was used. Continuous variables were compared using ANOVA. Categorical variables were analysed using the chi square test. Results: There was significant deficit in cognitive functioning in treatment naive schizophrenia and first episode BPAD compared to matched controls. The cognitive domain of visual retention was comparatively more impaired in patients with BPAD. Other cognitive domains did not show any difference between the two groups. The cognitive deficits in patients with bipolar disorder did not show any correlation with symptom severity (YMRS, HAM-D) whereas negative symptoms in schizophrenia showed positive correlation with dysfunction in memory scale and performance tests. Conclusion: The findings of our study was in line with the existing literature. The presence of cognitive deficits in treatment naiive schizophrenia and first episode bipolar disorder confirms the neuropathological hypothesis of the disorders and challenges the dichotomy of the two disorders.