Age Differences in Factors Associated With Insomnia Severity: A Comparative Study of Questionnaire Scores and Heart...

Primary insomnia exhibits diverse clinical profiles across age groups, yet the underlying mechanisms remain unclear. This study aimed to explore age-related differences in factors associated with insomnia severity.

Evaluating questionnaire scores and heart rate variability (HRV) parameters in young adult age (18-44 years, n = 124) and old adult age (≥45 years, n = 120) patients with primary insomnia. All participants underwent comprehensive assessments using the Athens Insomnia Scale (AIS), Insomnia Severity Index (ISI), and multiple psychological scales, alongside HRV analysis to evaluate autonomic nervous system function.

Significant between-group differences were observed in Morningness-Eveningness Questionnaire (MEQ) scores and State-Trait Anxiety Inventory (STAI) state anxiety scores, with young adult patients showing a higher prevalence of evening chronotype. All HRV parameters except high-frequency (HF) power differed significantly between age groups, indicating age-related autonomic dysregulation. Regression analyses identified distinct predictors of insomnia severity: insomnia severity in young adults was independently associated with depressive symptoms and chronotype, whereas that in older adults was predicted by anxiety symptoms and HRV parameters reflecting autonomic imbalance (low-frequency [LF]/HF ratio, mean R-R intervals [RRIs]).

These findings highlight age-dependent associations between insomnia severity, psychological factors, and autonomic function, suggesting that young adult insomnia may be more linked to depressive symptoms and chronotype, whereas old adult insomnia is strongly associated with anxiety and autonomic imbalance. This may inform age-tailored therapeutic strategies for primary insomnia.