Implementing Community-Based Psychosocial Interventions for Adults with Severe Mental Illness in High-Income Countries: A Rapid Scoping Review

Psychosocial interventions support functional recovery and social integration for people with severe mental illness (SMI); however, their implementation remains fragmented and inconsistent. This rapid scoping review maps the landscape of psychosocial interventions for adults with SMI in high-income countries, identifying their key components, implementation challenges, and strategies to optimise delivery. Following the Cochrane rapid review guidelines, we searched MEDLINE and CINAHL (January 2009 - May 2024) and conducted manual reference screening. Eligible studies focused on non-pharmacological, community-based interventions. Thematic analysis was used to identify implementation barriers and enablers. Of 8,624 screened records, 464 studies met inclusion criteria, covering 15 intervention types. Cognitive-focused interventions (n = 100) supported employment (n = 86), and behavioural therapies (n = 66) were most studied. Outcomes focused on symptom (n = 179), daily living skills (n = 160), and cognitive states (n = 157). Implementation was often constrained by systemic, organisational, and individual-level barriers. Systemic challenges included fragmented services, stigma, cultural and linguistic barriers, and economic constraints, highlighting the need for integrated care models, policy reforms, and culturally responsive approaches. Organisational challenges such as staff resistance, insufficient training, and resource limitations underscored the importance of leadership, stakeholder engagement, and investment. At the individual level, low motivation, logistical difficulties, trauma histories, and goal misalignment reduced engagement and retention, highlighting the need for flexible, person-centred, trauma-informed approaches, strong social networks, and a balance between structure and adaptability. Selecting, adapting, and funding psychosocial interventions remain complex. This review provides a foundation for future systematic reviews of homogeneous intervention subsets to better inform policy and practice.