Hazel E. Nelson

Cognitive functioning and symptomatology in chronic schizophrenia.

: Chronic schizophrenic patients in a long stay hospital were found to have low levels of intelligence (mean IQ of 80), which was attributed to the effects of substantial intellectual deterioration on below average pre-morbid levels of functioning. Patients with the lowest IQ scores had the least severe positive symptoms but symptomatology was not related to age or extent of intellectual decline. Speed of functioning was relatively more impaired than level of intellectual functioning, with cognitive speed being more affected than motor speed. The severity of negative but not positive symptoms was significantly related to the severity of bradyphrenia (cognitive slowing), a result which would be consistent with the notion of a subcortical pathology in patients with Type II schizophrenia.

Relationship of behavioural and symptomatic syndromes in schizophrenia to spatial working memory and attentional set-shifting ability

BACKGROUND Behavioural syndromes (thought disturbance, social withdrawal, depressed behaviour and antisocial behaviour) offer a different perspective from that of symptomatic syndromes on the disability that may be associated with schizophrenia. Few studies have assessed their relationship with neuropsychological deficits. We hypothesized that these syndromes may represent behavioural manifestations of frontal-subcortical impairments, previously described in schizophrenia. METHOD Long-stay inpatients (n=54) and community patients (n=43) with enduring schizophrenia were assessed, using measures of symptoms and behaviour and tests of executive functioning. The relationship between syndromes and neuropsychological function was assessed using multiple regression and logistic regression analyses. RESULTS Significant associations were found between performance on the spatial working memory task and the psychomotor poverty symptomatic syndrome, and between attentional set-shifting ability and both disorganization symptoms and the thought disturbance behavioural syndrome. These results were not explained by the effect of premorbid IQ, geographical location, length of illness or antipsychotic medication. Length of illness was an independent predictor of attentional set-shifting ability but not of working memory performance. CONCLUSION The specific relationship between negative symptoms and spatial working memory is consistent with involvement of the dorsolateral prefrontal cortex. The associations between difficulty with set-shifting ability and both disorganization symptoms and behaviours may reflect inability to generalize a rule that had been learned and impaired ability to respond flexibly. The specific relationship of illness duration to set-shifting ability may suggest progressive impairment on some executive tasks. The nature of these relationships and their neurobiological and rehabilitation implications are considered.

Primitive (developmental) reflexes, tardive dyskinesia and intellectual impairment in schizophrenia

Primitive reflexes, also known as higher cerebral, developmental or release reflexes, are present in foetal and infant life, and are found in certain organic brain diseases. They are normally regarded as non-localising signs of cerebral immaturity or dysfunction which are uncommon in the normal population. The main aims of this study were to find out whether recent reports of an association between primitive reflexes and severity of cognitive impairment in dementia and between primitive reflexes and tardive dyskinesia in schizophrenia could be replicated in a younger population of schizophrenic patients. Forty-eight schizophrenic patients (mean age 51 years) were assessed for primitive reflexes, involuntary movements and cognitive function, and 58% exhibited at least one primitive reflex and 23% at least two. No association was found between primitive reflexes and cognitive impairment or between primitive reflexes and tardive dyskinesia. These results fail to support the hypothesis that the presence of primitive reflexes in some schizophrenic patients indicates a vulnerability to tardive dyskinesia and intellectual decline with advancing age, but long-term prospective studies would be required to test this hypothesis adequately. Nevertheless, these findings support the notion of neurodevelopmental or neurodegenerative brain disease in at least a proportion of patients with schizophrenia.

Cognitive functioning and symptomatology in chronic schizophrenia

Chronic schizophrenic patients in a long stay hospital were found to have low levels of intelligence (mean IQ of 80), which was attributed to the effects of substantial intellectual deterioration on below average pre-morbid levels of functioning. Patients with the lowest IQ scores had the least severe positive symptoms but symptomatology was not related to age or extent of intellectual decline. Speed of functioning was relatively more impaired than level of intellectual functioning, with cognitive speed being more affected than motor speed. The severity of negative but not positive symptoms was significantly related to the severity of bradyphrenia (cognitive slowing), a result which would be consistent with the notion of a subcortical pathology in patients with Type II schizophrenia.