F109. CLINICAL PREDICTORS OF RESPONSE TO CLOZAPINE IN TREATMENT-RESISTANT SCHIZOPHRENIA

Abstract

Background: The use of clozapine for treatment-resistant schizophrenia is well documented. However, not all patients respond to clozapine, and there is a need to have better tools to recognize those who would benefit the most from this medicine. Our aim was to describe a cohort of patients who initiated clozapine treatment between 2014 and 2016 in a public psychiatric institute in Santiago, Chile to identify predictors of clinical response to clozapine. Method(s): Sociodemographic, clinical data and PANSS score before the initiation of clozapine use were analyzed. Parametric and non-parametric tests were used in the analysis. All patients prescribed clozapine under the age of 60 years old in a public psychiatric hospital were included. Subjects with comorbid neurological disorders were excluded. Discontinuation for any cause at 2 years of follow up and maximum doses of clozapine prescribed were used as proxy measures of response to clozapine. Result(s): 134 patients initiating clozapine were evaluated. 27.6% were female and their mean age was 32.41 (DE 11.7). 10.4% of the patients were homeless. Their mean duration of illness was of 3.06 years (DE 4.17) with a mean age of illness onset of 25.67 (DE 8.96). 34.9% of the patients initiating clozapine were amongst their first year after their first psychotic episode. Their mean PANSS disorganization dimension score was 19.27 (DE 6.33), PANSS negative dimension score 24.13 (DE 8.13), PANSS positive dimension score 19.7 (DE 6.83), PANSS hostility dimension score 12.27 (DE 5.36) and PANSS depression dimension score 4.47 (DE 2.77). At 2 years follow up they used a mean maximum clozapine dose of 385.42 (DE 152.99) mg and had an all cause discontinuation rate of 31.29%. Higher disorganization and negative dimension score at clozapine initiation was associated with higher maximum dose (p=0.041 and p=0.028 respectively). There was no association of any symptom dimension with any cause discontinuation outcome. Lower age at clozapine initiation was associated with lower discontinuation for any cause (p=0.006). Mean duration of illness, age of illness onset, being on the first episode of psychosis and gender were not associated with discontinuation for any cause or maximum dose used outcomes. Being homeless was associated with higher maximum dose used (p= 0.038). Discussion(s): Disorganization and negative dimension PANSS score could be a useful tool to predict response to clozapine treatment. Lower age at clozapine initiation was also a marker of good response to clozapine. This raises the possibility that an early use could prevent treatment failures, or otherwise earlier onset of psychosis could be a clozapine-responsive subgroup of psychosis. Family and social support could work as a protective factor for better clinical outcomes.