Obvious impairment of attention and processing speed in patients with schizoaffective disorder

Objective: Schizoaffective disorder (SAD) has features of both schizophrenia and bipolar disorder. This study identifies potential differences in cognitive function between patients with SAD and healthy controls. Whether the cognitive impairments in patients with SAD are associated with their clinical characteristics was also examined. Methods: This cross-sectional study involved 45 patients with SAD and 89 healthy control subjects. SAD was diagnosed using the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR). The participants’ cognitive functions were evaluated using the Brief Assessment of Cognition in Schizophrenia (BACS). The clinical psychopathology of patients with SAD was assessed using the Brief Psychiatric Rating Scale. Results: Patients with SAD exhibit significant deficits in all cognitive domains that are measured by the BACS, relative to healthy control subjects. Among all cognitive functions, attention and processing speed have the greatest discriminant validity for differentiating between SAD patients and healthy individuals. Additionally, bipolar type SAD patients performed worse in working memory than depressive type SAD patients, and treating with a mood stabilizer was associated with poor executive function. Conclusion: Patients with SAD exhibited significant deficits in all cognitive domains that are measured by BACS, but particularly in attention and processing speed. Whether the obvious deficits of attention and processing speed are specific to SAD warrants confirmation by comparison with cognitive profiles of patients with other psychotic disorders.