Association between polarity of first episode and solar insolation in bipolar I disorder.
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Authors
Bauer, M.
Glenn, T
Achtyes, E. D
Alda, M.
Agaoglu, E.
Altınbaş, K
McLoughlin, D.M.
...
Issue Date
2022
Type
Article
Language
en
Keywords
Alternative Title
Abstract
Objective
Circadian rhythm disruption is commonly observed in bipolar disorder (BD). Daylight is the most powerful signal to entrain the human circadian clock system. This exploratory study investigated if solar insolation at the onset location was associated with the polarity of the first episode of BD I. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area of the Earth.
Methods
Data from 7488 patients with BD I were collected at 75 sites in 42 countries. The first episode occurred at 591 onset locations in 67 countries at a wide range of latitudes in both hemispheres. Solar insolation values were obtained for every onset location, and the ratio of the minimum mean monthly insolation to the maximum mean monthly insolation was calculated. This ratio is largest near the equator (with little change in solar insolation over the year), and smallest near the poles (where winter insolation is very small compared to summer insolation). This ratio also applies to tropical locations which may have a cloudy wet and clear dry season, rather than winter and summer.
Results
The larger the change in solar insolation throughout the year (smaller the ratio between the minimum monthly and maximum monthly values), the greater the likelihood the first episode polarity was depression. Other associated variables were being female and increasing percentage of gross domestic product spent on country health expenditures. (All coefficients: P ≤ 0.001).
Conclusion
Increased awareness and research into circadian dysfunction throughout the course of BD is warranted.
Description
Citation
Bauer, M., Glenn, T., Achtyes, E. D., Alda, M., Agaoglu, E., Altınbaş, K., Andreassen, O. A., Angelopoulos, E., Ardau, R., Aydin, M., Ayhan, Y., Baethge, C., Bauer, R., Baune, B. T., Balaban, C., Becerra-Palars, C., Behere, A. P., Behere, P. B., Belete, H., ... Whybrow, P. C. (2022). Association between polarity of first episode and solar insolation in bipolar I disorder. Journal of Psychosomatic Research, 160, Article 110982. https://doi.org/10.1016/j.jpsychores.2022.110982