MicroRNA-195 predicts olanzapine response in drug-free patients with schizophrenia: A prospective cohort study.

Background: Disturbances of microRNA-195 have been implicated in the pathogenesis of schizophrenia. However, microRNA-195 levels in schizophrenia are controversial.

Aims: To the best of our knowledge, this is the first study to examine microRNA-195 levels in untreated schizophrenia patients and their relationship to olanzapine response.

Methods: We recruited 81 untreated schizophrenia patients and 96 healthy controls. The patients received 2 months olanzapine treatment. MicroRNA-195 levels in peripheral blood mononuclear cells were measured using quantitative real-time polymerase chain reaction testing. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale.

Results: No significant differences in microRNA-195 levels were found between patients and healthy controls ( 0.05). Olanzapine significantly reduced microRNA-195 levels after 2 months treatment ( 0.003). Interestingly, microRNA-195 levels decreased significantly in responders ( 0.010), but not in non-responders ( 0.05). Both baseline microRNA-195 levels ( 0.027,  0.030) and the reduction rate of microRNA-195 levels ( 0.034,  0.044) were positively associated with the reduction rate of Positive and Negative Syndrome Scale total score and general psychopathological subscale score. Multiple stepwise regression analysis revealed that baseline microRNA-195 level was an independent contributor to the reduction in Positive and Negative Syndrome Scale total score and the general psychopathological subscale score ( 0.018,  0.030). Finally, logistic regression analysis suggested that baseline microRNA-195 level can serve as a biomarker for response to olanzapine ( 0.037).

Conclusions: Our data indicate that microRNA-195 level may predict symptomatic improvement and olanzapine response in schizophrenia patients, suggesting that microRNA-195 should be considered as a potential therapeutic target for antipsychotics.