Community Mental Health Service Outpatient Co-Payment Thresholds and Psychotropic Adherence Among Informal-Sector Workers in Kenyan Counties: A Regression-Kink Estimation of Price Exposure

Outpatient co-payments for psychotropic medicines in Kenyan county community mental health services create a price exposure that informal-sector workers cannot smooth through insurance. The design treats the co-payment schedule as a continuous running variable with a legislated kink at the point where the county subsidy steps down, and estimates the change in the slope of adherence with respect to price at that kink. Identification rests on the absence of manipulation of the running variable and on continuity of potential adherence at the threshold, both of which are testable with administrative dispensing records. The paper derives the kink estimator, states the bias bound under imperfect compliance, and shows how county-level heterogeneity in informal-sector share and medicine stockouts enters the specification. It contributes a transferable identification strategy for price exposure in community mental health financing, a set of falsification tests suited to routine dispensing data, and a policy-relevant parameter: the local price elasticity of psychotropic adherence at the subsidy step-down. The design is presented as a protocol for estimation, not as a report of estimated effects.