The impact of disability onset on depressive symptoms: Longitudinal evidence from South Korea.

Depressive symptoms are a major mental health concern among people with disabilities in South Korea, yet little is known about how depressive symptoms change before and after disability onset, or how their levels differ between people with and without disabilities. Thus, we examined (a) changes in depressive symptoms before and after disability onset within people with disabilities, (b) comparisons between pre-onset levels of depressive symptoms in people with disabilities and the level of depressive symptoms in people without disabilities, (c) comparisons between post-onset levels of depressive symptoms in people with disabilities and the level of depressive symptoms in people without disabilities, and (d) changes in depressive symptoms associated with disability duration. Using the Korea Welfare Panel Study, we analyzed 152,152 person-wave observations from 13,643 individuals. Disability onset was identified using retrospectively reported onset age. We used linear mixed-effects models approximating a hybrid specification, with participant-level random intercepts. The levels of depressive symptoms among people with disabilities were higher after disability onset than before onset (β = 0.06, p = .015). Pre-onset depressive symptoms among people with disabilities were elevated relative to those of people without disabilities (β = 0.12, p < .001), as were post-onset depressive symptoms (β = 0.18, p < .001). Depressive symptoms did not differ significantly across years since disability onset. We suggest integrating mental health screening into disability diagnosis processes, particularly at early stages for individuals with progressive health decline. The persistent gap in depressive symptoms between people with and without disabilities underscores the need for stronger systemic support.