Subjective cognitive decline and mild behavioral impairment as predictors of health-related quality of life in cognitively normal older adults.

Objectives: Subjective cognitive decline (SCD) and mild behavioral impairment (MBI) are preclinical indicators of Alzheimer's disease and may negatively affect health-related quality of life (HRQoL). We examined the independent and combined effects of SCD, MBI, and depressive symptoms on HRQoL in cognitively unimpaired older adults.

Method: Ninety individuals aged >50 years were recruited from a psychiatric outpatient clinic. Participants completed the Geriatric Depression Scale-15 (GDS-15), Subjective Memory Complaints Questionnaire (SMCQ), and SF12 while informants completed the MBI-Checklist (MBI-C). Participants were categorized by SCD and MBI status. Group differences were examined using ANOVA, and hierarchical regression analyses models adjusting for sociodemographic.

Results: SCD and MBI were independently associated with lower Physical Component Summary (PCS-12) scores, with depressive symptoms partially mediating these relationships. Mental Component Summary (MCS-12) was primarily predicted by depressive symptoms. Impulse dyscontrol predicted poorer physical HRQoL, and affective dysregulation lower mental HRQoL.

Conclusion: SCD and MBI contribute to diminished HRQoL even without overt cognitive impairment, with depression acting as a mediator. Evaluating SCD alongside MBI provides a clearer understanding of early cognitive-behavioral changes and their burden on well-being. Findings underscore the need for integrated screening and early interventions in at-risk older adults.