Concurrent use of two long-acting injectable (LAI) antipsychotics in forensic patients with treatment-resistant schizophrenia: A case series

Objective Describe concurrent use of two long-acting injectable (LAI) antipsychotics in selected patients with treatment-resistant schizophrenia and persistent aggression at a forensic health facility. Evidence remains limited for this off-licence strategy. Methods Retrospective case series conducted at a specialist forensic psychiatric hospital in Melbourne, Australia. All inpatients using concurrent LAI antipsychotics between March 2022 and March 2023 were included ( N = 26). De-identified clinical data, including information for behavioral outcomes (Dynamic Appraisal of Situational Aggression [DASA]), institutional incidents, adverse effects and Defined Daily Dose (DDD) were extracted. Analyses were descriptive with exploratory unadjusted odds ratios. Results Concurrent LAI antipsychotics were predominantly prescribed to males (24/26, 92.3%) with chronic schizophrenia. Persistent aggression (22/26, 84.6%) was the commonest indication. Most frequent combination was olanzapine pamoate and zuclopenthixol decanoate and DDD median was 2.17 (range 0.48–10.13). Although the study design precluded identifying causal relationships, improvements were observed in DASA scores (21/26, 80.8%), incident frequency (22/26, 84.6%), and as-required-medication use (19/26, 73.1%). Adverse effects were common. Conclusions Selected forensic patients with high-risk behaviors may benefit from concurrent LAI antipsychotics. Enhanced side-effect monitoring and multidisciplinary oversight are required when used. Data interpretation was limited by observational design, concomitant medications, and absence of standardized symptom measures.