Evidence for the effectiveness of police-based pre-booking diversion programs in decriminalizing mental illness: A systematic literature review

Purpose: People with mental illnesses are at a significantly greater risk of police arrest than the general population. This pattern of arrests has been associated with a phenomenon referred to as the criminalization of mental illness such that people with mental illnesses are inappropriately diverted to the criminal justice system rather than to treatment. To decrease arrests of people with mental illnesses experiencing a crisis, pre-booking diversion programs have been developed to intervene at the point of police contact. This systematic literature review examines the state of knowledge regarding the effectiveness of police-based pre-booking diversion programs by addressing the question, “What is the evidence for the effectiveness of police-based pre-booking diversion programs in reducing arrests (i.e., reducing criminalization) of people with mental illnesses?” Methods: Systematic literature searches of seven databases were performed during May 2017. The searches sought to identify studies that examined the effectiveness of pre-booking diversion programs in decreasing arrests. A multi-phase screening process was completed independently by two pairs of reviewers as well as a risk of bias review. Results: A total of 2,750 unique citations were identified. Of these, 4 met the inclusion/exclusion criteria; all were from the US. Three of the studies examined the effectiveness of Crisis Intervention Teams and one study looked at a mobile crisis program. Two of the studies were at moderate risk of bias and two at high risk. Conclusions: This review indicates that this line of inquiry is still developing. There are a number of gaps yet to be filled. The current evidence for the effectiveness of police-based pre-booking diversion programs in reducing arrests (i.e., reducing criminalization) of people with mental illnesses is limited. However, these studies indicate there is moderate evidence that these programs increase linkages to mental health services.