Community Mental Health Service Traditional Healer Referral Pathway Entry and Delayed First Contact in Nigerian Catchments: A Multistate Model Estimation of Pathway Exposure

Delayed first contact with formal mental health services in Nigerian catchments is frequently attributed to traditional healer consultation, yet the pathway structure that produces delay remains poorly specified. The model is specified as a continuous-time Markov process with transition intensities that vary by catchment-level supply conditions, and the estimand is derived as a function of those intensities. Because no primary catchment data were available for estimation, the paper is framed as a methodological and theoretical contribution: it formalises the pathway, derives the exposure estimand, and demonstrates how routine service data would identify it. The contribution is a specification that separates pathway entry from pathway delay, shows that the two are governed by different intensities, and clarifies why cross-sectional reports of healer prevalence cannot identify delay. Implications for catchment-level service planning and for the design of referral registers are discussed.