Paliperidone Palmitate: A Breakthrough Treatment for Schizophrenia? A Review on Patient Adherence Levels, Healthcare Resource Utilization and Costs

International guidelines suggest long-term antipsychotic therapies for treating schizophrenia; however, medication com-pliance remains a critical issue in schizophrenia. Paliperidone palmitate (PP) is a second-generation antipsychotic long-acting injectable (SGA-LAI) approved for the treatment of schizophrenia. To date, the majority of studies on PP compliance patterns did not use specific instruments to assess medications' adherence, have been performed in not naturalistic samples and present partially overlapping populations. We conducted a systematic review in which we aimed to review the current knowledge on PP-LAI adherence levels and to describe healthcare resource utilisation and costs related to PP-LAI treatment. The evaluation has been conducted by searching in different databases (PubMed, Ovid, Scopus, and Cochrane Library) from inception to September 2022. Our findings suggest that paliperidone palmitate should be considered a good treatment strategy for patients affected by schizophrenia: PP showed both a good efficacy and tolerability and better adherence patterns and more favourable healthcare resource utilisation and costs, compared to OA.