Assessing violence risk in first-episode psychosis: external validation, updating and net benefit of a prediction tool (OxMIV)

Whiting, Daniel; Mallett, Sue; Lennox, Belinda; Fazel, Seena

Abstract

Violence perpetration is a key outcome to prevent for an important subgroup of individuals presenting to mental health services, including early intervention in psychosis (EIP) services. Needs and risks are typically assessed without structured methods, which could facilitate consistency and accuracy. Prediction tools, such as OxMIV (Oxford Mental Illness and Violence tool), could provide a structured risk stratification approach, but require external validation in clinical settings. We aimed to validate and update OxMIV in first-episode psychosis and consider its benefit as a complement to clinical assessment. A retrospective cohort of individuals assessed in two UK EIP services was included. Electronic health records were used to extract predictors and risk judgements made by assessing clinicians. Outcome data involved police and healthcare records for violence perpetration in the 12 months post-assessment. Of 1145 individuals presenting to EIP services, 131 (11%) perpetrated violence during the 12 month follow-up. OxMIV showed good discrimination (area under the curve 0.75, 95% CI 0.71 to 0.80). Calibration-in-the-large was also good after updating the model constant. Using a 10% cut-off, sensitivity was 71% (95% CI 63% to 80%), specificity 66% (63% to 69%), positive predictive value 22% (19% to 24%) and negative predictive value 95% (93% to 96%). In contrast, clinical judgement sensitivity was 40% and specificity 89%. Decision curve analysis showed net benefit of OxMIV over comparison approaches. OxMIV performed well in this real-world validation, with improved sensitivity compared with unstructured assessments. Structured tools to assess violence risk, such as OxMIV, have potential in first-episode psychosis to support a stratified approach to allocating non-harmful interventions to individuals who may benefit from the largest absolute risk reduction.

Citation

Whiting, D., Mallett, S., Lennox, B., & Fazel, S. (2023). Assessing violence risk in first-episode psychosis: external validation, updating and net benefit of a prediction tool (OxMIV). BMJ Mental Health, 26(1), Article e300634. https://doi.org/10.1136/bmjment-2022-300634

• Journal Article Type: Article
• Acceptance Date: Dec 29, 2022
• Online Publication Date: Jun 14, 2023
• Publication Date: Jun 14, 2023
• Deposit Date: Jan 29, 2024
• Publicly Available Date: Jan 30, 2024
• Journal: BMJ Mental Health
• Electronic ISSN: 2755-9734
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 26
• Issue: 1
• Article Number: e300634
• DOI: https://doi.org/10.1136/bmjment-2022-300634
• Keywords: Calibration, Clinical Reasoning, Humans, Retrospective Studies, Psychotic Disorders - diagnosis, Adult psychiatry, Forensic psychiatry, Schizophrenia & psychotic disorders, Violence - prevention & control
• Public URL: https://nottingham-repository.worktribe.com/output/22450037
• Publisher URL: https://mentalhealth.bmj.com/content/26/1/e300634