Moderating Effects of BADL and IADL on the Relationship between Cognitive Function and Depression in Older Adults

Objective : The purpose of this study was to analyze the moderating effects of Basic Activities of Daily Living (BADL) and Instrumental Activities of Daily Living (IADL) on the relationship between cognitive function and depression in older adults. Specifically, this study aimed to identify the need for differentiated intervention strategies for mental health management of older adults in a super-aged society. Methods : This study utilized raw data from the 2023 Survey of Living Conditions and Welfare Needs of Korean Older Persons conducted by the Ministry of Health and Welfare. A total of 10,078 participants aged 65 and older were analyzed, with variables including cognitive function (MMSE-K), depression (SGDS-K), Activities of Daily Living (K-ADL), and Instrumental Activities of Daily Living (K-IADL). Process Macro (Model 1) was used to analyze the moderating effects of BADL and IADL on the relationship between cognitive function and depression. Results : Cognitive function was found to significantly reduce depression levels, with both BADL and IADL significantly moderating this relationship. Johnson-Neyman analysis revealed that when BADL scores were below 11.177 and IADL scores were below 17.521, higher cognitive function was associated with lower depression levels. Conversely, when BADL scores exceeded 14.919 or IADL scores exceeded 21.896, a paradoxical relationship emerged where higher cognitive function was associated with increased depression levels. Conclusion : The results confirmed that the relationship between cognitive function and depression can vary depending on the level of daily living activities in older adults. These findings suggest that a personalized approach considering individual functional levels is necessary for the prevention and management of depression in older adults. Particularly for older adults with high functional dependency, complex interventions that combine cognitive training with mental health support and coping strategy education may be effective.