OBJECTIVE: Sleep complaints are often associated with anxiety and depression, but the specific complaints related to each syndrome are poorly characterized, especially in older adults.

The gap

Consensus across the literature

Supporting evidence — 6 representative gaps

• The interrelationships among insomnia, frailty, anxiety, and cognitive function in middle-aged and older adults: a cross-sectional study (2026) · doi

  Several limitations of the present study warrant acknowledgment. First, the cross-sectional design precludes causal inference regarding the temporal sequence or directionality of the observed associations. Longitudinal investigations are necessary to elucidate the dynamic interrelationships among insomnia, frailty, anxiety symptoms, and cognitive decline over time. Second, the sample was recruited exclusively from a single tertiary hospital, which may limit the generalizability of the findings to community-dwelling or more heterogeneous populations. Third, all assessments relied on subjective self-report and rater-administered instruments. The incorporation of objective measures—such as actigraphy, polysomnography, or neuroimaging biomarkers—would substantially strengthen the valid- ity and reproducibility of future studies. Fourth, this study did not differentiate among clinically distinct insomnia subtypes, including sleep-onset insomnia, sleep-mainte- nance insomnia, and early-morning awakening. Given the patho- physiological heterogeneity of insomnia, different phenotypes may exhibit divergent associations with affective symptoms and cogni- tive outcomes. Consequently, it remains uncertain whether the moderated mediation model identified herein applies uniformly across specific insomnia presentations. Future studies with larger, phenotypically well-characterized samples are needed to address this question. Fifth, the present investigation examined dimensional symptom severity on the HAMA, and MoCA-B rather than formally diag- nosed clinical syndromes. Accordingly, the findings pertain to the burden of anxiety symptoms, depressive symptoms, and cognitive symptoms in the context of insomnia and frailty, rather than to established psychiatric or neurocognitive disorders. Moreover, cognitive performance was assessed globally using a brief screening tool, which precludes inferences regarding domain-specific impair- ments (e.g., in memory, executive function, or attentional control). Future studies should employ comprehensive neuropsychological batteries to determine whether the observed effects are specific to certain cognitive domains. Sixth, the HAMA includes items that assess insomnia symp- toms (e.g., difficulty falling asleep, restless sleep), which may partially overlap with the PSQI measure of insomnia severity. This potential item overlap could inflate the observed association between insomnia and anxiety and should be considered when interpreting the insomnia–anxiety relationship. Future studies may

  Keywords: insomnia symptoms anxiety cognitive future observed sleep speci present precludes regarding associations among frailty ndings
• Sleep Quality and Cognitive Life Expectancy in the United States (2025) · doi

  While strong associations between sleep quality, cognitive functioning, and mortality are well-documented, the mechanisms underlying sleep's role in cognitive status and life expectancy (LE) across different cognitive states remain unclear.

  Keywords: cognitive sleep strong associations quality functioning mortality well documented mechanisms underlying role status life expectancy
• The role of presleep negative emotion in sleep physiology (2011) · doi

  Although daytime emotional stressful events are often presumed to cause sleep disturbances, the few studies of stressful life events on sleep physiology have resulted in various and contradictory findings.

  Keywords: stressful events sleep daytime emotional often presumed cause disturbances life physiology resulted various contradictory
• Roles of Sleep Quality, Self-Efficacy, and Coping Style in the Frailty of Community-Dwelling Older Adults: A Cross-Sectional Study (2024) · doi

  OBJECTIVES: Although the association between sleep disorders and frailty has been well established, little is known about the cognitive appraisal mechanisms underlying this association.

  Keywords: association objectives sleep disorders frailty well established little known cognitive appraisal mechanisms underlying
• Subjective sleep characteristics associated with anxiety and depression in older adults: a population‐based study (2014) · doi

  OBJECTIVE: Sleep complaints are often associated with anxiety and depression, but the specific complaints related to each syndrome are poorly characterized, especially in older adults.

  Keywords: complaints objective sleep often associated anxiety depression specific related syndrome poorly characterized especially older adults
• Big Five Personality Traits and Insomnia Severity in Adults: The Conditional Role of Anxiety and Depression (2026) · doi

  Insomnia is common and associated with both personality traits and psychological distress, yet it remains unclear how stable dispositional characteristics relate to insomnia severity across levels of emotional distress.

  Keywords: insomnia distress common associated personality traits psychological remains unclear stable dispositional characteristics relate severity across