The Subjective Memory Complaints Questionnaire: a systematic review of psychometric properties, clinical applications, and neurobiological correlates.

Subjective memory complaints (SMCs) are early markers of cognitive decline. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, synthesizes the psychometric properties and clinical utility of the Subjective Memory Complaints Questionnaire (SMCQ) using data from 2009 to 2025. From 407 records, 163 studies were analyzed across categories including diagnostic accuracy, intervention outcomes, and pathological associations. The SMCQ demonstrated excellent internal consistency (Cronbach's α: 0.82 to 0.92) and robust screening performance, with an area under the curve (AUC) of 0.84 for self-reports and 0.92 for informant reports regarding dementia. While validated in 15 languages across 25 countries, research remains heavily concentrated in Korean Alzheimer's disease (AD) cohorts, with limited evidence for non-AD dementias. Despite these geographical limitations, the SMCQ is a reliable, globally adapted tool for identifying individuals requiring further cognitive assessment. This study received no specific funding and was not preregistered.