The influence of switching from oral risperidone to risperidone long-acting injection on the clinical symptoms and cognitive function in schizophrenia

Abstract

This study was a comparative investigation of the effects on clinical symptoms and cognitive function of switching schizophrenia patients from oral risperidone to risperidone long-acting injection (RLAI) compared with a control group that continued receiving oral risperidone. The subjects were 21 patients who had been diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Their clinical symptoms were assessed using the positive and negative syndrome scale (PANSS), and their cognitive function was assessed using the Wisconsin Card Sorting Test: Keio Version (KWCST) to assess executive function, and the St Marianna University School of Medicine's Computerized Memory Test (STM-COMET) to assess memory and concentration. No significant differences in clinical symptom improvement efficacy were seen between the group that was switched to RLAI and the control group. No significant differences were seen between the two groups in the mean change from baseline in any of the KWCST tests. The mean changes from baseline on the STM-COMET memory scanning test and memory filtering test were significantly greater in the group that switched to RLAI than in the control group. Furthermore, patients with RLAI needed less biperiden, even though they had similar risperidone-equivalent daily dosages as the group with oral risperidone. The results of this study suggested that switching from oral risperidone to RLAI may affect motor processing function and attention improvement efficacy by allowing the dosage of anti-Parkinson's medication to be reduced.