Engagement strategies in an assertive outreach context: a mixed-methods systematic review.

Background: Assertive outreach (AO) is a systematic approach to engage vulnerable patients with serious mental illness.

Aims: This review aims to provide a comprehensive analysis of engagement strategies in relation to principles of the AO model to clarify effective components of AO, better understand engagement in an AO context, and consider encompassing change mechanisms.

Methods: A systematic mixed-methods review was completed from 1806 to December 2022 (no pre-registration). Articles meeting the inclusion criteria were rated for methodological quality using the JBI scales and thematic synthesis using a meta-aggregative approach. Reporting was according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement.

Results: Eighteen articles met the inclusion criteria. The literature was defined by three main themes: definition and perspectives of engagement; key principles of AO in relation to engagement; and additional principles and strategies enhancing engagement.

Conclusion: Despite the heterogeneity in defining engagement, the relationship between AO professionals and patients emerged as crucial in the process of engagement. Subsequently, the four key principles of AO emerged as central to promoting engagement. Finally, we identified a number of additional principles that are considered crucial in the engagement process in AO. The review concludes with recommendations for future research and the implementation of AO in routine clinical care.