Paliperidone 3-monthly (PP3M) long-acting injection has proven efficacy and effectiveness in schizophrenia. Little is known of its effectiveness in other diagnoses.

All patients starting PP3M were followed up for 2 years. Main outcome measures were relapse and discontinuation from PP3M. Post hoc we examined outcomes in those switched back to one monthly paliperidone (PP1M) long-acting injection.

Overall, 186 patients were followed-up. At the 2-year end point, 110 patients (59%) were still receiving PP3M, and 129 (70%) were receiving some form of paliperidone long-acting injection. Discontinuation from paliperidone long-acting injections (PPLAIs) was more likely with a nonschizophrenia diagnosis (hazard ratio [HR] for continuation 0.429 [95% confidence intervals (CI) – 0.21, 0.87 p = 0.018)), and prior clozapine use [in PP3M patients; HR for discontinuation 1.87 [95% CI – 1.05, 3.30 p = 0.032]). Relapse occurred in 20 (11%) of those receiving PP3M. Relapse on PP3M and PPLAIs was more likely in nonschizophrenia diagnosis (HR 0.17 for remaining relapse-free [95% CI – 0.06, 0.50; p = 0.001]; HR 0.21 [95% CI – 0.08, 0.58 p = 0.002], respectively), polypharmacy in PP3M patients (HR for relapse 7.91 [95% CI – 3.73, 22.9; p < 0.001]) and PPLAI patients (HR for relapse 6.45 [95% CI – 2.49, 16.5; p < 0.001]), and prior clozapine use in PP3M patients (HR for relapse 6.11 [95% CI – 1.82, 20.5; p = 0.003]) and PPLAI patients (HR for relapse 4.52 (95% CI – 1.51, 13.5; p = 0.007).

Outcomes with PP3M are excellent in practice, even when used outside its formal license. PP3M was relatively more effective in those with an F20 schizophrenia diagnosis and in those never before considered for or prescribed clozapine.