Clinical improvement, relapse and treatment adherence with paliperidone palmitate 1-month formulation: 1-year treatment in a naturalistic outpatient setting

Purpose: To evaluate paliperidone palmitate 1-month formulation (PP1M) effectiveness in a naturalistic outpatient psychiatric setting.Materials and methods: We collected data from 50 outpatients affected by schizophrenia disorders treated with PP1M for 12 months in an Italian Mental Health Department. After analyzing selected demographic, clinical and pharmacological variables, we performed mirror analysis to compare psychiatric hospitalizations and urgent consultations required by the same patient 6 and 12 months before and after PP1M implementation (primary outcome). We analyzed clinical improvement in symptom (Clinical Global Impression-severity and improvement) and functioning (Global Assessment of Functioning) scales and drop-out rate during the 12-month PP1M treatment (secondary outcome). Data were statistically analyzed.Results: The mean PP1M dose was 93.5 mg (±27.7 SD) with a mean interval between each injection of 27.1 d (±4.5 SD). Twenty-three patients (46%) reported adverse effects (sexual dysfunctions, weight gain and extrapyramidal symptoms).Fifteen patients (30%) dropped out after 137.2 d (±103.1 SD) on average: six due to the lack of therapeutic adherence, six due to inefficacy and three due to adverse events. The drop-out patients presented more severe clinical profile in CGI-S and GAF scores at T0 in comparison with others. At mirror analysis, 12-month but not 6-month PP1M treatment statistically significantly reduced psychiatric hospitalizations (t = 2.3, p < .05) and urgent consultations (t = 2.1, p < .05). Both scale scores showed statistically significant improvement at T12 in comparison to T0.Conclusions: This naturalistic study indicates that long-term PP1M treatment was safe and effective in preventing hospitalizations and urgent consultations as well as in improving clinical course.