Predictors of Short-Term Treatment Response to Risperidone in First-Episode Schizophrenia

Kim, Sang Wook; Hong, Kyung Sue

Abstract

OBJECTIVE
The purpose of this study is to identify the predictors of short-term treatment response to rieperidone from first-episode schizophrenia. METHOD: Eighteen first episode schizophrenic patients were recruited and received treatment with risperidone for 8 weeks. Clinical response was measured using Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression(CGI) scale. Demographic(age, sex), clinical(family history, age at onset, premorbid and baseline levels of functioning, premorbid IQ, duration of illness, baseline psychopathologies, extrapyramidal symptoms after 1 week treatment) and neurocognitive number of correct responses and reaction time for Continuous Attention Test) characteristics and their correlations with treatment response indices(improvement rates in positive, negative and general psychopathology subscales of PANSS) were analysed. Stepwise multiple regression was performed to identify the predictors for each treatment response index.
RESULTS
Significant improvement was observed for each subscale of PANSS during 8 weeks of treatment. Longer duration of illness before treatment was highly related to poor treatment response for each response index. Extrapyramidal symptoms after 1 week treatment was also related with poor treatment response. According to the regression analysis, duration of illness strongly predicts all response indices (deltaR2=0.42-0.79), and the higher functioning level in the past predicts the improvement rate in general psychopathology.
CONCLUSION
These results suggest that early diagnosis and intervention could increase the rate of short-term treatment response to risperidone. In addition to the duration of illness, extrapyramidal symptoms of early treatment phase and the level of premorbid functioning also predict treatment responses.