Seasonal variation in affective and other clinical symptoms among high-risk families for bipolar disorders in an Arctic population

• Published in: International Journal of Circumpolar Health
• Main Authors: Sami Pirkola, Heidi A. Eriksen, Timo Partonen, Tuula Kieseppä, Juha Veijola, Erika Jääskeläinen, Eeva-Maija Mylläri-Figuerola, Paula M. Salo, Tiina Paunio
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2015
• Subjects: bipolar disorder; seasonal variation; endophenotype; mood; distress; high risk family; Arctic medicine. Tropical medicine; RC955-962; Arctic; Beck; Arctic Population; Circumpolar Health; Fennoscandia; International Journal of Circumpolar Health
• Online Access: https://doi.org/10.3402/ijch.v74.29671; https://doaj.org/article/ce9ebeb718d94a71adf1789616b1f6ef

Background: In bipolar disorder (BD), seasonality of symptoms is common and disturbances in circadian rhythms have been reported. Objectives: We identified high-penetrance families in a geographically restricted area in Northern Fennoscandia and studied the seasonal variation of clinical symptoms among BD subjects and their healthy relatives. Design: We explored the clinical characteristics of subjects living in Northern Fennoscandia, with extreme annual variation in daylight. Among known indigenous high-risk families for BD, we compared the affected ones (N=16) with their healthy relatives (N=15), and also included 18 healthy non-related controls from the same geographical area. Seasonal fluctuation in clinical measures was followed up at the 4 most demarcated photoperiodic time points of the annual cycle: around the summer solstice and autumn equinox in 2013, the winter solstice in 2013/2014, and the spring equinox in 2014. In the baseline, lifetime manic symptoms [Mood Disorder Questionnaire (MDQ)] and morningness–eveningness questionnaire type (MEQ) were registered, whereas in the follow-up, depressive [Beck Depression Inventory (BDI)] and distress [General Health Questionnaire (GHQ-12)] symptoms and alcohol consumption and sleep were recorded. Results: Possibly indicative or statistically significant differences in symptoms between the affected subjects and their healthy relatives were the BDI winter (13.3 vs. 2.6, t=−2.51, p=0.022) and spring scores (12.6 vs. 3.2, t=−1.97, p=0.063) and GHQ winter (4.2 vs. 0.82, t=−2.08, p=0.052) and spring scores (3.8 vs. 0.82, t=−1.97, p=0.063). Scores were higher among the affected subjects, exceeding a possibly diagnostic threshold (10 and 3) at all the time points, and without the notable seasonality which was observed among the healthy relatives. In the overall population, MDQ and MEQ scores had an inverse correlation (−0.384, significant at 0.016), indicating increased lifetime manic behaviour among “the night owl” chronotype subjects. Conclusions: In an Arctic ...