Contributions of clinical neuropsychology to the study of schizophrenia.

Abstract

Clinical neuropsychological findings are examined with respect to competing hypotheses about localized neuropathology in schizophrenia. Two general models of structural and functional impairment are described. The first addresses deficits in cortical/subcortical processes concerned with arousal, attention, and higher cortical functions. The second addresses impairments in the balance of lateralized functions consistent with left hemisphere overactivation. Empirical data provide support for both models, and suggest that the explanatory power of these models may vary when they are applied to different subtypes of schizophrenia.

Executive function in first-episode schizophrenia

“…First, they distinguish first-episode patients from chronic schizophrenic patients since the latter have difficulties with the WCST (see Levin et al 1989 ; and are more impaired on the CANTAB attentional set shifting task than on the planning and spatial working memory tasks (Elliott et al , 1997Pantelis et al 1997). Thus, it appears that the nature of the executive impairment changes over the course of the illness.…”

“…For example, the delineation of aberrant cognitive processes will contribute to an understanding of the neurobiological basis of the disorder and also to the planning of rehabilitation aimed at reducing the long-term social consequences of the illness. Thus, the neuropsychological deficits associated with schizophrenia have been investigated extensively (see Levin et al 1989 ;. Several studies have described global performance deficits (e.g.…”

Advances in endophenotyping schizophrenia

“…Verbal memory deficits are found among relatives of schizophrenia patients (70,71). The deficits implicate left temporal-hippocampal dysfunction (66,67,(72)(73)(74), and dysfunction in a prefrontal-temporal limbic network (74,75). Reduced hippocampal volumes among relatives of patients and smaller hippocampal volumes in multiplex versus simplex relatives and controls is consistent with the hypothesis that increased genetic loading for schizophrenia affects the neural substrates of verbal memory (76,77).…”

The relationship between regional cerebral blood flow and the Wisconsin Card Sorting Test in negative schizophrenia

“…2 In contrast, schizophrenic patients show cognitive deficits compared to normal controls in the Wisconsin Card Sorting Test (WCST), a task commonly used to study concept formation in the information processing of subjects. 3,4 Studies have been conducted to investigate the regional cerebral flood flow (rCBF), especially in the frontal lobe, of both normal subjects and schizophrenic patients while tak-ing the WCST. [5][6][7][8][9][10][11][12][13] Rezai et al showed that the WCST primarily activates the left dorsolateral prefrontal cortex of normal adults.…”