Long-term care insurance pilot exposure and severe-depression risk among older adults with baseline severe IADL impairment: a panel difference-in-difference-in-differences analysis.

Against the backdrop of rapid population ageing and a steadily rising risk of disability, long-term care has become a central issue in China’s social security system. In 2016, China launched the long-term care insurance (LTCI) pilot programme, marking a substantive new phase in the development of a formal long-term care system. As an important institutional innovation, LTCI is expected not only to ease the caregiving burden faced by older adults with disabilities and their families, but also to improve the allocation of medical resources, care arrangements, and family well-being. Existing studies show that LTCI can reduce hospital utilisation, shorten length of stay, and lower inpatient expenditure and out-of-pocket spending [–]. It may also substitute formal care for some acute medical services and informal care, although this substitution appears to vary across income groups []. Beyond healthcare utilisation, LTCI has been associated with improvements in self-rated health and cognitive function, reductions in disability, and lower levels of unmet care needs [–]. These benefits may extend to the family level by reducing caregiving burden and alleviating adult children’s time, financial, and sleep pressures [–]. LTCI should therefore be understood not merely as a financing arrangement for medical care, but as a broader institutional mechanism that shapes caregiving relationships, resource allocation, and the well-being of older adults. A growing body of research has extended LTCI evaluation from healthcare utilisation to mental health, but much of this work still focuses on average depressive symptoms, subjective well-being, or broad mental-health indicators among older adults [–]. Existing heterogeneity analyses commonly compare disabled and non-disabled groups, rural and urban residents, or other broad social categories [–]. These studies are important, yet they do not fully address whether LTCI exposure changes the upper tail of the depression distribution among older adults whose care needs are already high at baseline. What remains unclear is not simply whether LTCI exposure changes average depressive symptoms, but whether it shifts the upper-tail risk of severe depression among older adults whose care needs are already high at baseline. There are theoretical reasons to expect this distributional question to matter. Severe IADL impairment implies greater care dependency, reduced autonomy in daily life, and higher psychological vulnerability. After a pilot programme is introduced, not all high-need older adults necessarily benefit equally from formal coverage: eligibility assessment, service availability, affordability, family coordination, and perceived support may differ across people and cities. For high-care-needs individuals, gaps between institutional coverage and usable, needs-matched support may accumulate as stress rather than immediately improving mental health []. For this reason, we hypothesise that policy exposure may be more likely to shift the upper tail of the depression distribution in high-care-needs populations than to alter the mean depressive-symptom level in the overall older population.