Winter is coming: nightmares and sleep problems during seasonal affective disorder

Abstract

<p> Sleep problems, especially nightmares and insomnia, often accompany<br /> depression. This study investigated how nightmares, symptoms of<br /> insomnia, chronotype and sleep duration associate with seasonal<br /> affective disorder, a special form of depression. Additionally, it was<br /> noted how latitude, a proxy for photoperiod, and characteristics of the<br /> place of residence affect the prevalence of seasonal affective disorder<br /> and sleep problems. To study these questions, data from FINRISK 2012<br /> study were used. FINRISK 2012 consists of a random population sample<br /> of Finnish adults aged 25–74 years (n = 4905) collected during winter<br /> from Finnish urban and rural areas spanning the latitudes of 60°N to<br /> 66°N. The Seasonal Pattern Assessment Questionnaire was used to<br /> assess symptoms of seasonal affective disorder. Participants with<br /> symptoms of seasonal affective disorder had significantly increased<br /> odds of experiencing frequent nightmares and symptoms of insomnia,<br /> and they were more often evening chronotypes. Associations between<br /> latitude, population size and urbanicity with seasonal affective disorder<br /> symptoms and sleep disturbances were generally not significant,<br /> although participants living in areas bordering urban centres had less<br /> sleep problems than participants from other regions. These data show<br /> that the prevalence of seasonal affective disorder was not affected by<br /> latitude.</p>