Nonlinear associations between insomnia symptoms and circadian preferences in the general population: Symptom-specific and lifespan differences in men and women

In a sample of 37,389 participants, different eveningness characteristics were found to have nonlinear relationships with insomnia symptoms.

• Later wake times and peak performance times are associated with increased insomnia symptoms, following an exponential pattern.
• Difficulties initiating sleep and experiencing nonrestorative sleep are linked to all eveningness characteristics examined.
• Difficulties maintaining sleep are specifically related to earlier bedtimes.
• The associations between eveningness and insomnia symptoms vary across different age groups but show less variation by sex.
• A combination of bedtime and wake time influences insomnia symptoms when resulting in an unusually long or short preferred time in bed.

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