Is there a negative impact of winter on mental distress and sleeping problems in the subarctic: The Tromsø Study

May Trude Johnsen,Rolf Wynn,Trond Bratlid

doi:10.1186/1471-244x-12-225

May Trude Johnsen, Rolf Wynn + Show 1 more

Open Access

https://doi.org/10.1186/1471-244x-12-225

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Abstract

BackgroundPrior studies have suggested that the darkness of winter impacts the level of mental distress and sleeping problems. Our study investigated whether people living in the sub-arctic had more sleeping problems or mental distress during winter.MethodsThe cross sectional population Tromsø Study was conducted in Tromsø, North Norway, at 69.4 degrees North and above the Arctic Circle. The study included entire birth cohorts and random samples of the population aged 30 to 87 years. Data was collected continuously from 1 October 2007 to the end of December 2008 except July. 8951 persons completed questionnaires including the HSCL-10 and the MCTQ.ResultsThere were no significant differences in the reporting of current mental distress depending on season. Significantly more reported current sleeping problems in winter than in the other seasons, and less sleeping problems was found in spring.ConclusionsIn this sub-arctic population, insomnia was most prevalent in winter, but there were no significant seasonal differences in mental distress. Although some people in the sub-arctic clearly are mentally negatively affected by the darkness of winter, the negative impact of winter on mental distress for the adult population is not conclusive.

Highlights

Prior studies have suggested that the darkness of winter impacts the level of mental distress and sleeping problems
The clinical symptoms of Midwinter Insomnia (MI) in Northern Norway, as described by Lingjaerde et al [2] start at the beginning of the Polar night period and last until the sun returns over the horizon
Stepwise backwards multiple logistic regression were performed, with ‘more sleeping problems than usual during the last couple of weeks’ and HSCL-10 score as outcome variables, and with participation season, socioeconomic variables, lifestyle variables and health variables as independent variables

Summary

Introduction

Prior studies have suggested that the darkness of winter impacts the level of mental distress and sleeping problems. Our study investigated whether people living in the sub-arctic had more sleeping problems or mental distress during winter. Many studies have focused on seasonality of mental distress and psychiatric symptoms, and in 1984, Rosenthal et al [1] first described the syndrome Seasonal Affective Disorder (SAD). MI severity varies from moderate difficulties in falling asleep to almost total inability to sleep during the whole night. These symptoms stand in contrast to the hypersomnia associated with SAD, which often continues into the day, leading to excessive daytime somnolence [9]

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