Eye movements and psychopathology in schizophrenia and bipolar disorder

The aim of this study was to examine multivariate patterns of relationships between oculomotor performance, psychopathology, and neuropsychology. Performance on smooth pursuit and saccadic eye movement tasks was assessed in three DSM-III-R diagnosis-based groups of subjects; normal (N = 55), schizophrenic (N = 29), and bipolar disorder (N = 26) and analyzed in relation to age, gender, scale for the Assessment of Negative Symptoms, Scale for the Assessment of Positive Symptoms, and Brief Psychiatric Rating Scale scores, Shipley intelligence quotient, and Wisconsin Card Sorting Test Performance. The greatest difference was a higher proportion of errors in the antisaccade task in the schizophrenic and bipolar groups, which was related to worse Wisconsin Card Sorting Test performance and was not accounted for by gender, age, education, or intelligence quotient. A significant gender and bipolar interaction showed bipolar women to have worse antisaccade performance. Abnormal smooth pursuit was more specific to schizophrenia. Antisaccade task and sine wave root-mean-square error were correlated in bipolar but not schizophrenic subjects. Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms scores had independent associations with the antisaccade task. Faster reaction times in the schizophrenic group to antisaccade errors were observed, suggesting an abnormality in visual attention processing and perhaps sensory gating functions. These results confirm abnormal smooth pursuit in schizophrenia and suggests that impairments in saccadic function are less specific to diagnostic group. Oculomotor performance and psychopathology seem related in complex ways to age, gender, intelligence quotient, and executive neuropsychological and possibly visual attention functions.