ABSTRACT
OBJECTIVES: This study investigated the validity of positive-negative dichotomy model by comparing the differences of neurocognitive function in the specific symptom subgroups of schizophrenia. METHODS: Factor analysis was performed on 14 items of the Positive and Negative Syndrome Scale (PANSS) among 71 inpatients with schizophrenia. All patients were assigned to one of specific symptom subgroups based on a ratio score and compared the neurocognitive distinction of each subgroups with normal control group, which was composed of 60 healthy persons without psychiatric illness. Neurocognitive functions include sustained attention, sensory register, executive function, attention and concentration, and verbal memory and learning obtained using Degraded Stimulus Continuous Performance Test, Span Apprehension Task, Wisconsin Card Sorting Test, Digit Span, and Rey Auditory Verbal Learning Test respectively. RESULTS: Three factors, positive, negative and disorganized, were yielded from factor analysis on 14 items of the PANSS. Three symptom subgroups showed the differential neurocognitive profiles. Disorganized symptom subgroup showed significant deficits in the sustained attention, sensory register, executive function, attention and concentration, and verbal memory and learning compared with the normal controls. Negative symptom subgroup showed significant deficits in the sustained attention, sensory register, executive function, and verbal memory and learning. Positive symptom subgroup showed significant deficits only in the sustained attention and sensory register compared with the normal controls. No significant differences were noted in the sustained attention, sensory register, attention and concentration, and verbal memory and learning among three symptom subgroups. But the disorganized symptom subgroup showed a significant deficit in the executive function compared to the positive symptom subgroup. CONCLUSIONS: These results support that three symptom dimensions including disorganization may be more valid than the positive-negative symptom dichotomy in the dimensions of schizophrenic symptoms.