Treatment resistance in a Chilean cohort of patients with first episode of psychosis.

Poster A102, Monday, October 8, 11:30 am - 1:00 pm, Essex Ballroom

Cristián Mena1,2, Alfonso González - Valderrama1,3, Barbara Iruretagoyena4, Juan Undurraga1,5, Carmen Castañeda1, Carlos Gallardo1, Ruben Nachar1,3, Nicolás Crossley4,6; 1Early Intervention Program, J. Horwitz Psychiatric Institute, Santiago, Chile, 2National Unit of Clozapine Pharmacovigilance, J. Horwitz Psychiatric Institute, Santiago, Chile, 3School of Medicine, Universidad Finis Terrae, Chile, 4Department of Psychiatry, School of Medicine. Pontificia Universidad Católica de Chile, 5Department of Neurology and Psychiatry, Faculty of Medicine, Clínica Alemana Universidad del Desarrollo. Santiago, Chile, 6Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London UK.

Purpose: Antipsychotic treatment resistance in first episode psychosis (FEP) is an important problem with a paucity of reports. Our aim was to describe a cohort of Chilean patients who developed resistance after that FEP was diagnosed. Methods: Analysis of clozapine prescription patterns, used as a real-world proxy marker for treatment-resistance, in a cohort of patients discharged from an Early Intervention ward in Chile. Sociodemographic variables and doses of clozapine were analysed. The initial prescription was divided in early onset period (within 1 year of treatment onset), medium-term onset (1 to 5 years of treatment), and late onset (>5 years). Survival analysis was performed using national databases of clozapine monitoring system. Results: 230 patients were diagnosed with a non – affective FEP between 2008 and 2014. 42 patients (18.3%) started clozapine in the follow up. There was no difference in average age and gender between clozapine and non – clozapine users. Average dose of clozapine was 305 mg (SD 177 mg). Annual probability of being prescribed clozapine was 0.096 (95%CI0.06-0.013) within the early period (<1 year); 0.025 (95%CI 0.01-0.04) during the medium stage (1 to 5 years); and 0.006 (95%CI 0-0.004) at the late stage (>5 years). All – cause of clozapine discontinuation at 12 months was 4.8%. Conclusions: Our results highlight that treatment resistance is frequently present from the onset of psychosis and is relatively common in a Latin American cohort. This would support the idea that some subtypes of TR psychosis are categorically distinct since beginning of the illness.

Topic Area: Psychopharmacology

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