| Summary: | This thesis attempted to investigate the relationship between symptom expression, medication effects, outcome status and neuropsychological functioning in schizophrenia. As the heterogeneity of schizophrenia is now widely accepted, symptom ratings from the comprehensive Positive and Negative Syndrome Scale (Kay et al., 1986) were entered in to a factor analysis after the work of Liddle (1987) and Liddle and Barnes (1990). The factor analysis of symptoms was carried out with patients at both the acute stage of illness and at the chronic stage. Almost twice as many chronic patient subjects were used in the latter study than had been used before (n=66). The acute stage analysis was seen as a preliminary investigation as only twenty six patients were recruited. This reflects the difficulty in recruiting early stage floridly ill patients for demanding psychiatric and neuropsychological assessment. The emergent factors, at each stage, were correlated with neuropsychological performance on an array of executive, psychomotor and hemispatial neglect tests. Neuropsychological assessment was also compared with healthy control data to assess the degree, if any, of impairment from the norm, independent of symptoms. In the chronic stage study, four factors coined reality distortion, poverty of sociability and affect, disorganisation and excitability were generated. Poverty of sociability and affect was related to impaired short term working memory, episodic memory and semantic verbal fluency. Disorganisation significantly correlated with episodic memory functioning and disinhibition of inappropriate responding. None of the other factors were directly related to neuropsychological performance. The relation between episodic memory functioning and poverty of sociability and affect was explained in terms of poor cognition due to developmental experience and the retention and use of socially appropriate schema. Disorganisation appeared to be underpinned by possible frontal type organisational difficulties in the correct temporal ordering of information for recall. At the acute stage, five factors emerged reflecting a paranoid state, poverty of affect, disorganisation/poverty of sociability and delusions.
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