Head-to-head comparison of 1-year aripiprazole long-acting injectable (LAI) versus paliperidone LAI in comorbid psychosis and substance use disorder: impact on clinical status, substance craving, and quality of life

Background: To overcome nonadherence in patients with psychosis switch to long-acting injectable (LAI) antipsychotic formulations is adopted. Most oral versus LAI comparisons showed similar antipsychotic responses. Psychoses often overlap with substance use disorder (SUD). Head-to-head LAI comparisons have hitherto focused only on non-comorbid populations. Objective: The objective of this study was to compare two LAIs, administered for 12 months, in initially hospitalized patients with psychosis comorbid with SUD in their clinical and quality of life (QoL) outcomes. Patients and methods: Inpatients were recruited during 2016 and switched randomly to 400 mg intramuscular aripiprazole monohydrate (AM) (N=50) or to 100 mg intramuscular paliperidone palmitate (PP) once-monthly (N=51); patients were discharged and followed up for 12 months. Patients were rated at baseline and after 1 year through the Clinical Global Impression scale - severity (CGIs), substance craving intensity was rated through a visual analog scale for substance craving, and QoL through the World Health Organization (WHOQOL-BREF) scale. We addressed confounders with backward stepwise logistic regression and three-way analysis of variance. Results: PP were older and had more cases of schizophrenia spectrum and less bipolar disorders than AM, but AM had a stronger craving for substances at baseline. Both LAIs were associated with significant improvements in all outcomes, with AM displaying stronger effect sizes than PP. The two groups did not differ on baseline WHOQOL-BREF scores in any domain, but at the 1-year follow-up, AM fared better on all domains. The two groups did not differ in final severity, but PP scored higher than AM in craving at the 1-year endpoint. Limitation: The CGIs is not a refined tool for severity and the substance craving may be subject to recall bias. Conclusion: 1-year AM and PP was followed by improved clinical status and QoL and reduced substance craving in a population with psychosis and SUD comorbidity. AM, compared to PP, improved craving and QoL at the 1-year follow-up.