The Interaction Among Depressive Symptoms, Pain, and Frailty in Middle‐Aged and Older Adults: A Longitudinal Cross‐Lagged Panel Analysis

Background: Depressive symptoms, pain, and frailty interactions in middle‐aged and older adults do have longitudinal research support, yet the currently available evidence remains insufficient for a comprehensive understanding. This study aimed to examine their interrelationships and underlying mechanisms. Methods: This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS), which includes four assessments for depressive symptoms, pain, and frailty over 7 years. We included 4961 participants aged 45 years and older in our analysis. We employed cross‐lagged panel models (CLPMs) and random intercept CLPMs (RI‐CLPMs) to analyze the bidirectional temporal relationships at the between‐person and within‐person levels. Results: Cross‐lagged panel analysis revealed bidirectional associations between depressive symptoms and pain. A reciprocal predictive relationship was also identified between frailty and pain. After controlling individual differences with the RI‐CLPM, depressive symptoms continued to positively predict pain during subsequent periods. However, the predictive effect of pain on subsequent depressive symptoms turned nonsignificant. Although a cross‐lagged relationship remained between pain and frailty, it showed a declining trend. Limitations: While engagement in depressive symptoms, pain, and frailty was assessed via questionnaire, long measurement intervals may not capture short‐term fluctuations in the state of each variable. Conclusions: This study differentiated within‐ and between‐individual effects, uncovering distinct lagged effects of pain, depression, and frailty across levels. It underscored the importance of jointly assessing these conditions and integrating within‐ and between‐individual differences to formulate and execute targeted interventions.