There is a growing need for real world data on long-term clinical and health resource utilization outcomes. The main purpose of this study was to establish the effects of 1-monthly Paliperidone Palmitate (PP1M) on treatment continuation and hospital stay in routine clinical practice. This is a naturalistic, 6-year mirror-image study examining retention and hospitalization rates 3 years pre-PP1M and 3 years post-PP1M initiation. One hundred seventy-three patients were included; 120 (70%) had a primary diagnosis of schizophrenia and 53 (30%) other diagnosis. In total, 77% of patients continued PP1M for one year, 66% for two years and 55% for three years. For the patients who continued with PP1M for 3 years (n = 95), the mean number of hospital admissions decreased significantly from 1.44 to 0.53 and the mean number of bed days from 93 to 29 bed days 3 years before and 3 years after PP1M initiation (P < 0.001). The group of patients with schizophrenia who continued for 3 years (n = 79) demonstrated similar outcomes. The introduction of PP1M had a significant impact on long-term clinical outcomes. More than half of patients were still continuing on PP1M at 3 years after initiation and had no admission during 3 years follow-up.