BackgroundA number of naturalistic studies have investigated paliperidone palmitate (PP) using proxy measures of effectiveness. An unexplored option is to examine the utility of the mental health clustering tool (MHCT), which is used in UK clinical practice to measure patient well-being and is linked to allocation of resources. This study evaluated the effectiveness of PP using the MHCT, the Health of the Nation Outcome Scales (HoNOS), and, for comparison, more conventional outcome measures.MethodsThis was a naturalistic, 1-year evaluation of PP (n=50) in schizophrenia as well as a comparator antipsychotic drugs group. Changes in the MHCT cluster-score cost ranking and four HoNOS-derived factors were analyzed using a mixed-model statistical analysis to explore the utility of these measures.ResultsAt 1 year, 30 patients (60%) continued PP treatment. The mean “cluster-score cost ranking” (−1.5) and Severe Disturbance factor scores (−1.1) were significantly lower (p-value [adjusted] =0.0003, p-value [adjusted] =0.002, respectively) after 1 year of antipsychotic treatment but no differences were found between PP and the comparator antipsychotic drugs group. Patients prescribed PP were 1.8 times (95% CI 1.1−3.1) more likely to be discharged from hospital than those in the comparator antipsychotic drugs group.ConclusionPP’s continuation rate after 1 year made the study similar to the existing evaluations, and it was possible to prospectively evaluate antipsychotic effectiveness using the novel measures although these did not discriminate between PP and the comparator group. The investigation illustrates that in principle these novel measures are meaningful in naturalistic study designs.