Sleep characteristics, chronotype and winter depression in 10–20‐year‐olds in northern European Russia

The prevalence of winter depression (SADW) in the study population was 8.4%.

• Four variables predicted the likelihood of SADW: sex (higher in females), age (increases with age), latitude (higher in the North), and position in the time zone (higher in the West).
• Youths with SADW exhibited later sleeping and waking times, longer sleep latencies, more severe sleep inertia, shorter total sleep durations, and lower sleep efficiencies.
• The effects of SADW on sleep characteristics were more pronounced on school days.
• Significant phase delays in the sleep-wake rhythm and severe social jetlag were observed in females with SADW, but not in males.
• There are notable differences in sleep characteristics and chronotype between individuals with SADW and those without.

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