The heterogeneity of schizophrenic information processing and negative versus positive symptoms

In this study, 20 schizophrenic patients were subdivided into a schizophrenia group with positive symptoms (N = 11) and a schizophrenia group with negative symptoms (N = 9) by Andreasen's rating scales: the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. These groups were compared with 17 normal controls and 17 subjects with a closed head injury. Indices of information processing derived from Coglab, a multiparadigmatic cognitive test battery developed by Spaulding et al., were used for comparison. The "negative" schizophrenia subjects were characterized by a more pervasive deficient information-processing capacity than the "positive" schizophrenia subjects. The deficits both groups had in common were, however, not of equal severity. The closed head injury group, who served as an indirect control for the presumed generalized deterioration in the negative schizophrenia group, did not compare very well to this latter group. The results are discussed in relation to the question of whether the information-processing deficiencies stem from a single causal process, or whether these deficiencies are independent and associated with many etiological pathways.