Mechanisms to Support Interventions Involving the Police When Responding to Persons Experiencing a Mental Health Crisis: A Realist Review

Mental health crisis interventions involving police originated in the United States. In England and Wales, street triage services (a UK term used to describe urgent mental health and police interventions) were piloted in 2013. These models involve police and mental health services working together to ensure individuals receive the required support. Evaluation findings have shown inconsistent outcomes based on studies predominately limited to single sites. Evaluations to date have lacked theoretical consideration of the contexts and mechanisms triggering outcomes for service users. This review used a realist approach to develop an explanatory understanding of what happens in interventions involving the police responding to individuals experiencing a mental health crisis (underlying mechanisms), the contextual conditions surrounding the implementation of these interventions (context) and the outcomes produced as a result. The review was conducted using a two-stage process. Stage one generated initial programme theories, which informed a systematic literature search (stage two), which further developed, tested theories. From 6461 potentially relevant papers identified in stage two, 19 papers were included. Extracted data were themed, prior to developing narrative and formulating programme theories. In six programme theories, spanning four themes were developed: role legitimacy of police as responders to mental health crises, using technology, complex decision-making and responding to distress. Findings indicate that central to successful interventions involving the police in mental health crisis responses is the requirement of social relationships and joint working between police and mental health services to foster trust. Presented findings contribute to a more detailed understanding of mechanisms within interventions involving the police in mental health crisis responses. By generating evidence-based understandings of the effective components of these support interventions, this research has potential to inform development of future such support at a time of significant policy changes impacting on the role of police as responders to mental health crises.