medwireNews: Diabetes exacerbates cognitive impairment in patients with schizophrenia, particularly in immediate memory and attention, say researchers.
They suggest that this additive effect on memory “may be associated with the extensive hippocampal abnormalities caused by the abnormal glucose metabolism.”
The team led by Xu-Feng Huang (University of Wollongong, New South Wales, Australia) found that, compared with 190 healthy individuals, cognitive performance was significantly impaired in 127 patients with schizophrenia, 55 patients with schizophrenia and diabetes, and 106 patients with diabetes.
Patients with schizophrenia plus diabetes had the worst cognitive performance overall. They performed significantly worse than diabetes-only and schizophrenia-only patients in immediate memory, and had lower total RBANS (Repeatable Battery for the Assessment of Neuropsychological Status) scores, albeit only significantly so compared with schizophrenia-only patients (73.6 vs 79.2).
They also performed significantly worse than diabetes-only patients in attention, and there were nonsignificant trends for worse performances in attention and visuospatial/constructional functioning compared with schizophrenia-only patients.
The additive effects of diabetes and schizophrenia on immediate memory and overall RBANS score remained significant after taking into account demographic variables and clinical variables such as duration of illness, antipsychotic treatment, and hospitalization.
The researchers also report in PLoS One that RBANS total score correlated modestly with schizophrenia patients’ Positive and Negative Syndrome scores, their duration of current antipsychotic treatment, and the presence of diabetes.
They cite previous research reporting an association between hippocampal activation and the neural underpinnings of memory and propose that “impaired glucose regulation/availability contributes to the vulnerability for memory deficits in schizophrenia, which may be associated with the extensive hippocampal abnormalities in schizophrenia.”
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