t083804-Bauer-et-al-suicide.pdf (823.53 kB)
Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder
journal contribution
posted on 2021-01-01, 00:00 authored by M Bauer, T Glenn, E D Achtyes, M Alda, E Agaoglu, K Altınbaş, O A Andreassen, E Angelopoulos, R Ardau, E A Vares, M Aydin, Y Ayhan, C Baethge, R Bauer, B T Baune, C Balaban, C Becerra-Palars, A P Behere, P B Behere, H Belete, T Belete, G O Belizario, F Bellivier, R H Belmaker, F Benedetti, Michael BerkMichael Berk, Y Bersudsky, Ş Bicakci, H Birabwa-Oketcho, T D Bjella, C Brady, J Cabrera, M Cappucciati, A M P Castro, W L Chen, E Y W Cheung, S Chiesa, M Crowe, A Cuomo, S Dallaspezia, M Del Zompo, P Desai, Seetal DoddSeetal Dodd, M Donix, B Etain, A Fagiolini, F T Fellendorf, E Ferensztajn-Rochowiak, J G Fiedorowicz, K N Fountoulakis, M A Frye, P A Geoffroy, A Gonzalez-Pinto, J F Gottlieb, P Grof, B C M Haarman, H Harima, M Hasse-Sousa, C Henry, L Høffding, J Houenou, M Imbesi, E T Isometsä, M Ivkovic, S Janno, S Johnsen, F Kapczinski, G N Karakatsoulis, M Kardell, L V Kessing, S J Kim, B König, T L Kot, M Koval, M Kunz, B Lafer, M Landén, E R Larsen, M Lenger, U Lewitzka, R W Licht, C Lopez-Jaramillo, A MacKenzie, H Ø Madsen, S A K A Madsen, J Mahadevan, A Mahardika, M Manchia, W Marsh, M Martinez-Cengotitabengoa, K Martiny, Y Mashima, D M McLoughlin, Y Meesters, I Melle, F Meza-Urzúa, M Y Ming, S Monteith, M Moorthy, G MorkenAbstract
Background
Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries.
Methods
Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries).
Results
This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01.
Conclusion
A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
Background
Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries.
Methods
Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries).
Results
This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01.
Conclusion
A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
History
Journal
International Journal of Bipolar DisordersVolume
9Issue
1Article number
ARTN 26Pagination
1 - 14Publisher
SpringerLocation
Berlin, GermanyPublisher DOI
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ISSN
2194-7511eISSN
2194-7511Language
EnglishPublication classification
C1 Refereed article in a scholarly journalUsage metrics
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