A tool to evaluate proportionality and necessity in the use of restrictive practices in forensic mental health settings: the DRILL tool (Dundrum restriction, intrusion and liberty ladders).

Background: Prevention of violence due to severe mental disorders in psychiatric hospitals may require intrusive, restrictive and coercive therapeutic practices. Research concerning appropriate use of such interventions is limited by lack of a system for description and measurement. We set out to devise and validate a tool for clinicians and secure hospitals to assess necessity and proportionality between imminent violence and restrictive practices including de-escalation, seclusion, restraint, forced medication and others.

Methods: In this retrospective observational cohort study, 28 patients on a 12 bed male admissions unit in a secure psychiatric hospital were assessed daily for six months. Data on adverse incidents were collected from case notes, incident registers and legal registers. Using the functional assessment sequence of antecedents, behaviours and consequences (A, B, C) we devised and applied a multivariate framework of structured professional assessment tools, common adverse incidents and preventive clinical interventions to develop a tool to analyse clinical practice. We validated by testing assumptions regarding the use of restrictive and intrusive practices in the prevention of violence in hospital. We aimed to provide a system for measuring contextual and individual factors contributing to adverse events and to assess whether the measured seriousness of threating and violent behaviours is proportionate to the degree of restrictive interventions used. General Estimating Equations tested preliminary models of contexts, decisions and pathways to interventions.

Results: A system for measuring adverse behaviours and restrictive, intrusive interventions for prevention had good internal consistency. Interventions were proportionate to seriousness of harmful behaviours. A 'Pareto' group of patients (5/28) were responsible for the majority (80%) of adverse events, outcomes and interventions. The seriousness of the precipitating events correlated with the degree of restrictions utilised to safely manage or treat such behaviours.

Conclusion: Observational scales can be used for restrictive, intrusive or coercive practices in psychiatry even though these involve interrelated complex sequences of interactions. The DRILL tool has been validated to assess the necessity and demonstrate proportionality of restrictive practices. This tool will be of benefit to services when reviewing practices internally, for mandatory external reviewing bodies and for future clinical research paradigms.