Cognitive Function Deficits In High-Risk, First-Episode, And Chronic Schizophrenia

Background: Cognitive deficits are believed to be the primary deficits in schizophrenia, persisting even after reduction or resolution of primary symptoms of hallucinations and delusions. Cognitive deficits reportedly occur in all studies of schizophrenia, but whether they progress in linear severity from subjects who are at high risk for schizophrenia to first episode and later to chronic schizophrenia needs further investigation. We present preliminary results from a study of cognitive deficits in normal controls, 3 categories of high-risk subjects, and patients with first-episode and chronic schizophrenia. Methods: We report cognitive deficit results from a larger study that focused on epigenetic biomarkers in the lymphocytes of patients with schizophrenia in China. We assessed cognitive function in normal controls, in 3 groups at high risk for schizophrenia (HR)—(1) subjects with a family member with schizophrenia (FAMHR), (2) subjects with prodromal symptoms of schizophrenia (PRODROMALHR), and (3) subjects with both prodromal symptoms and a family history (ULTRAHR)—and in first-episode schizophrenia (FSZ) and chronic schizophrenia (CSZ) patients. Cognitive functions were evaluated in all subjects using the MATRICS battery. All patients were evaluated by family history and the PANSS interview. HR subjects were also evaluated with the SIPS interview. Results: MATRICS battery scores for combined HR subjects generally suggest declines in cognitive performance and are intermediate between controls and subjects with schizophrenia. These declines in HR subjects were statistically significant (P < .05) compared to controls in the MATRICS components of Overall Composite Score, Speed of Processing, Visual Learning, and Reasoning-Problem Solving. FSZ and CSZ showed more severe deficits but were not significantly different from each other on any of the MATRICS domain scores. Within the subcategories of HR subjects, the FAMHR group did not significantly differ from controls on any cognitive measure, although they had slightly lower mean scores, but a statistically significant decline was seen in the PRODROMALHR group. However, FSZ and CSZ had significantly more severe cognitive deficit scores than the PRODROMALHR group. We are currently analyzing the relationship between cognitive decline and symptom scores on SIPS and PANSS. Conclusion: Significant cognitive deficits are observed in HR subjects before development of schizophrenia, but become prominent only in HR subjects who develop prodromal symptoms. These symptoms worsen until the onset of FSZ but do not to appear to worsen throughout progression of the illness in this sample.