Effects of switching to long-acting injectable risperidone from oral atypical antipsychotics on cognitive function in patients with schizophrenia

Objective To investigate changes in cognitive function and clinical features following a switch from oral atypical antipsychotics (AAPs) to long-acting injectable risperidone (LAIR) in patients with schizophrenia. Methods Thirty-six patients with schizophrenia treated with oral AAPs participated in this open-label, 26-week study. Cognitive functions were measured at baseline and at 12 and 26 weeks. The secondary outcome measures included the Positive and Negative Syndrome Scale (PANSS), Social and Occupational Functioning Assessment Scale (SOFAS), Scale for Unawareness of Mental Disorder (SUMD), and measurements for extrapyramidal symptoms. Results Significant improvements in cognitive function were observed in the backward Digit Span Test, Verbal Learning Test, Wisconsin Card Sorting Test, correct responses on the Continuous Performance Test, and Trail Making Test part B following a switch to LAIR. Scores on the PANSS, SOFAS, SUMD, and the Simpson-Angus Rating Scale also improved significantly. Most improvements in neurocognitive function were not correlated with clinical measures. Weight gain and hyperprolactinemia were the most common adverse events. Conclusions Switching from oral AAPs to LAIR improved cognitive function including vigilance, verbal learning and memory, executive function, sustained attention, and visuomotor speed in patients with schizophrenia. It was also effective for improving psychotic symptoms, social functioning, and insight. Copyright (c) 2009 John Wiley & Sons, Ltd.