Objective: Cognitive impairments in schizophrenia are associated with different symptom subtypes of schizophrenia. It has been suggested that cognitive functions in the paranoid type of schizophrenia were better protected. Here, we examine how neuropsychological measures jointly differentiate patients with paranoid schizophrenia from non-paranoid patients.
Methods: Fifty-three patients with schizophrenia, 26 paranoid and 27 non-paranoid, were included in the study. The mean age was 38.0 +/- 9.1 in the paranoid patients and 39.8 +/- 16.4 in the non-paranoid patients. A comprehensive test battery was administered to evaluate a broad range of cognitive functions including attention, executive functions, memory, language, and complex perceptual processing.
Results: Patients with paranoid schizophrenia demonstrated higher performance than non-paranoid patients on measures of selective attention/executive function (Stroop Color-Word Interference Test) (F=6.07, p<0.01) and learning/memory functions (Serial Digit Learning Test) (F=8.43, p<0.00).
Conclusion: Our findings suggest that cognitive differences might reflect underlying neurocognitive processes and may differentiate subtypes of schizophrenia.