Readiness for collaboration: an implementation science perspective on integrating Nigerian religious leaders into mental health systems - findings from the CLERIC study.

Introduction: The mental health treatment gap in low- and middle-income countries, particularly Nigeria is profound. Religious leaders serve as de facto community gatekeepers for mental distress. This study, forming the quantitative and mixed-methods component of the CLErgy and Religious leader Involvement in Community mental health project, moves beyond acknowledging this role by systematically assessing the collaboration readiness of Nigerian religious leaders, identifying its predictors and classifying leaders into distinct implementation profiles to inform task-sharing initiatives. Methods: A cross-sectional, explanatory mixed-methods study was conducted in Lagos State, Nigeria. Of 255 religious leaders approached, 207 Christian and Muslim leaders were enrolled (response rate 81.2%). A supplementary sample of 25 mental health professionals was recruited (response rate 71.4%). Surveys and focus group discussions were administered in English and Yoruba; the focus group sessions lasted 75-90 min. Collaboration readiness was assessed using a validated 10-item scale alongside the Mental Health Literacy Scale, the Community Attitude Towards Mental Illness Scale-16 and a structured barrier assessment. Analyses included multiple linear regression, structural equation modelling (SEM) and latent class analysis (LCA). Two focus groups (n=15) and open-ended healthcare professional survey responses were analysed thematically. Results: Overall readiness was moderate (M=25.8/40), with 71.5% demonstrating moderate-to-high readiness. Notably, 48.8% had never made a medical referral, revealing a persistent know-do gap. Regression (R²=0.64) identified mental health literacy (β=0.41), education (β=0.26) and prior training (β=0.23) as strongest predictors. SEM confirmed education improves readiness primarily via literacy (indirect effect=0.13). LCA identified four implementation profiles: implementation ready (18.4%), conditionally ready (31.9%), reluctantly engaged (29.5%) and implementation resistant (20.2%). Four qualitative themes emerged: structural constraints, ideological conflict, trust barriers and conditional openness from healthcare providers. Knowledge gaps and trust deficits were bidirectional. Conclusions: Substantial collaboration potential exists among Nigerian religious leaders and appears to be shaped by a combination of intervention-sensitive factors, such as mental health literacy and training exposure, and less directly modifiable structural characteristics, such as educational background and service access. A stratified, bidirectional implementation strategy tailored to distinct readiness profiles is essential to bridge the mental health treatment gap.