Response suppression deficits in treatment-naïve first-episode patients with schizophrenia, psychotic bipolar disorder and psychotic major depression

Abstract 

Recent evidence indicates common genetic, neurobiological, and psychopharmacological aspects of schizophrenia and psychotic affective disorders. Some similarities in neurocognitive deficits associated with these disorders have also been reported. We investigated performance on antisaccade and visually-guided saccade tasks in treatment-naïve first-episode psychosis patients (schizophrenia n=59, major depression n=15, bipolar disorder n=9), matched non-psychotic major depression patients (n=40), and matched healthy individuals (n=106). All psychosis groups displayed elevated antisaccade error rates relative to healthy individuals. Antisaccade latencies were elevated in schizophrenia, but no significant error rate or latency differences were observed among psychosis groups. For schizophrenia only, shorter visually guided saccade latencies were associated with higher antisaccade error rates. Schizophrenia was also the only group without a significant relationship between visually guided and antisaccade latencies. Reflexive saccades were unimpaired except in psychotic unipolar depression, where saccades were hypometric. As in schizophrenia, antisaccade abnormalities are present in affective psychoses, even early in the course of illness and prior to treatment. Disturbances in frontostriatal systems are believed to occur in both affective psychoses and schizophrenia, potentially causing some similar cognitive abnormalities across psychotic disorders. However, the distinct pattern of dysfunction in schizophrenia across oculomotor paradigms suggests possible unique causes of their observed oculomotor performance deficits.

Keywords: Antisaccade, Visually guided saccade, Eye movements, Frontostriatal system