Membrane fatty acid levels as a predictor of treatment response in chronic schizophrenia.

Abnormal fatty acid composition in neural membranes, that is, the balance between essential polyunsaturated fatty acids (EPUFAs) and saturated fatty acids, has been suggested to be related to the psychotic symptoms and cognitive impairment of schizophrenia. This study was conducted to test the hypothesis that the ability of atypical antipsychotic drugs to ameliorate positive symptoms and cognitive function relevant to daily living would be predicted by baseline EPUFAs concentrations in the erythrocyte membrane in subjects with schizophrenia. A total of 24 actively psychotic patients with schizophrenia participated in the study. After blood drawing, they were treated with olanzapine or perospirone. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for Assessment of Negative symptoms (SANS), as well as the script tasks, a measure of event schema recognition, were administered at baseline and 3months after the start of treatment. Erythrocyte membrane fatty acid levels were analysed using a gas chromatography system. Scores of SAPS and SANS, as well as script task performance, were improved during treatment with either antipsychotic drug. Regression analysis indicates baseline EPUFAs concentrations were positively and negatively related with percent improvement of positive symptoms and script task performance, respectively. The results of this study suggest composition of phospholipids in the erythrocyte membrane provide a feasible marker to predict treatment response in patients with schizophrenia.

Essential polyunsaturated fatty acids and social cognition in schizophrenia.

Abnormal metabolism of essential polyunsaturated fatty acids (EPUFAs), a component of phospholipids in neural membranes, has been suggested to be related to the pathophysiology of schizophrenia. The purpose of this study was to examine the relationship between EPUFA concentrations in erythrocyte membranes, a peripheral measure of phospholipid composition in the brain, and clinical variables, such as cognitive performance relevant to social functions, in patients with schizophrenia. Erythrocyte membrane levels of EPUFAs, saturated fatty acids, and monounsaturated acids were measured in 25 patients with schizophrenia and 32 age- and gender-matched 32 normal volunteers. The script tasks, a measure of social cognition, and the Brief Psychiatric Rating Scale were administered to the patients. The levels of EPUFAs, but not those of saturated or monosaturated fatty acids, were significantly lower in patients than in normal controls. The degree of a decrease in EPUFA levels was positively correlated with severity of positive symptoms and impairment of frequency judgment performance on the script tasks, while no such correlations were found with negative symptoms, attention as measured by the Wechsler Adult Intelligence Scale-Revised-Digit Span, or verbal memory as measured by the Auditory Verbal Learning Test. These results provide the first suggestion for a contribution of decreased levels of EPUFAs to impaired social cognition, as represented by event schema, in patients with schizophrenia.