2026 ECNP Congress

PS04-4197

Functional outcomes and clinical response to long-acting injectable ISM risperidone: a retrospective study

Gonçalo Soares — C. Oliveira · Hospital Júlio de Matos - ULS São José, Equipa Comunitária de Saúde Mental de Loures, Lisboa, Portugal

2026 ECNP Congress

Background

Long-acting injectable (LAI) antipsychotics are widely used in the management of chronic psychotic disorders, particularly in esquizofrenia, due to their advantages in improving adherence and reducing relapse rates. While their efficacy in symptom control is well established, their impact on functional outcomes remains less consistently documented. Functional recovery, encompassing social, occupational, and personal domains, represents a critical dimension of patient-centered care. In this context, evaluating both symptomatic improvement and real-world functioning is essential to better understand the overall benefits of LAI treatment in routine clinical practice.

Objectives

To assess clinical response and functional outcomes in patients treated with LAI ISM Risperidone, and to explore the relationship between symptom improvement and functional gains, as well as potential associations with illness duration.

Methods

A retrospective observational study was conducted including 22 patients undergoing treatment with LAI ISM Risperidone for at least six months. Demographic and clinical data were collected from electronic medical records, including age, gender, diagnosis, duration of illness, treatment history, and adverse effects. Clinical response was evaluated using the Clinical Global Impression scale, specifically the severity (CGI-S), improvement (CGI-I), and efficacy index (CGI-E). Functional status was assessed using the Global Assessment of Functioning, with scores recorded retrospectively for the period prior to LAI initiation and at the most recent follow-up. Functional improvement was defined as the difference between post-treatment and pre-treatment GAF scores (ΔGAF). Additional real-world functional indicators were collected, including autonomy in medication management, engagement in occupational activity, and participation in leisure activities. Statistical analyses included descriptive statistics, paired-sample comparisons of GAF scores, and Spearman correlation analyses to explore associations between variables.

Results

The mean GAF score increased significantly from 36.4 ± 11.8 prior to LAI initiation to 62.1 ± 18.1 at follow-up (p < 0.001), corresponding to a mean functional improvement (ΔGAF) of 25.7 points. Clinical improvement, as measured by CGI-I, showed a strong and statistically significant negative correlation with ΔGAF (Spearman’s ρ = -0.79, p < 0.001), indicating that greater symptomatic improvement was associated with larger functional gains. No significant correlation was found between duration of illness and functional improvement (ρ = -0.02, p = n.s.). Descriptive analysis of additional functional indicators suggested parallel improvements in real-world functioning, including increased autonomy and engagement in structured activities, although these findings were not formally tested due to sample size limitations.

Conclusions

Treatment with LAI ISM Risperidone was associated with significant improvements in global functioning in this cohort. The strong correlation between clinical response and functional gain highlights the relevance of symptom stabilization as a driver of broader recovery outcomes. The absence of an association between illness duration and functional improvement suggests that meaningful gains may be achievable even in patients with long-standing illness. These findings support the role of LAI ISM Risperidone not only in symptom control but also in enhancing real-world functioning. Further studies with larger samples are warranted to confirm these results and to better characterize predictors of functional recovery.

References

  1. Correll CU, Litman RE, Filts Y, Llaudó J, Naber D, Torres F, Martínez J. Efficacy and safety of once-monthly Risperidone ISM® in schizophrenic patients with an acute exacerbation. NPJ Schizophr. 2020 Nov 25;6(1):37. doi: 10.1038/s41537-020-00127-y. PMID: 33239746; PMCID: PMC7688968.
  2. Filts Y, Litman RE, Martínez J, Anta L, Naber D, Correll CU. Long-term efficacy and safety of once-monthly Risperidone ISM® in the treatment of schizophrenia: Results from a 12-month open-label extension study. Schizophr Res. 2022 Jan;239:83-91. doi: 10.1016/j.schres.2021.11.030. Epub 2021 Nov 27. Erratum in: Schizophr Res. 2022 Aug;246:258-259. doi: 10.1016/j.schres.2022.06.037. PMID: 34847501.