@article{2996992,
    title = "Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder",
    author = "Bauer, M. and Glenn, T. and Achtyes, E.D. and Alda, M. and Agaoglu, E. and Altınbaş, K. and Andreassen, O.A. and Angelopoulos, E. and Ardau, R. and Vares, E.A. and Aydin, M. and Ayhan, Y. and Baethge, C. and Bauer, R. and Baune, B.T. and Balaban, C. and Becerra-Palars, C. and Behere, A.P. and Behere, P.B. and Belete, H. and Belete, T. and Belizario, G.O. and Bellivier, F. and Belmaker, R.H. and Benedetti, F. and Berk, M. and Bersudsky, Y. and Bicakci, Ş. and Birabwa-Oketcho, H. and Bjella, T.D. and Brady, C. and Cabrera, J. and Cappucciati, M. and Castro, A.M.P. and Chen, W.-L. and Cheung, E.Y.W. and Chiesa, S. and Crowe, M. and Cuomo, A. and Dallaspezia, S. and Del Zompo, M. and Desai, P. and Dodd, S. and Donix, M. and Etain, B. and Fagiolini, A. and Fellendorf, F.T. and Ferensztajn-Rochowiak, E. and Fiedorowicz, J.G. and Fountoulakis, K.N. and Frye, M.A. and Geoffroy, P.A. and Gonzalez-Pinto, A. and Gottlieb, J.F. and Grof, P. and Haarman, B.C.M. and Harima, H. and Hasse-Sousa, M. and Henry, C. and Høffding, L. and Houenou, J. and Imbesi, M. and Isometsä, E.T. and Ivkovic, M. and Janno, S. and Johnsen, S. and Kapczinski, F. and Karakatsoulis, G.N. and Kardell, M. and Kessing, L.V. and Kim, S.J. and König, B. and Kot, T.L. and Koval, M. and Kunz, M. and Lafer, B. and Landén, M. and Larsen, E.R. and Lenger, M. and Lewitzka, U. and Licht, R.W. and Lopez-Jaramillo, C. and MacKenzie, A. and Madsen, H.Ø. and Madsen, S.A.K.A. and Mahadevan, J. and Mahardika, A. and Manchia, M. and Marsh, W. and Martinez-Cengotitabengoa, M. and Martiny, K. and Mashima, Y. and McLoughlin, D.M. and Meesters, Y. and Melle, I. and Meza-Urzúa, F. and Ming, M.Y. and Monteith, S. and Moorthy, M. and Morken, G. and Mosca, E. and Mozzhegorov, A.A. and Munoz, R. and Mythri, S.V. and Nacef, F. and Nadella, R.K. and Nakanotani, T. and Nielsen, R.E. and O‘Donovan, C. and Omrani, A. and Osher, Y. and Ouali, U. and Pantovic-Stefanovic, M. and Pariwatcharakul, P. and Petite, J. and Pfennig, A. and Ruiz, Y.P. and Pilhatsch, M. and Pinna, M. and Pompili, M. and Porter, R. and Quiroz, D. and Rabelo-da-Ponte, F.D. and Ramesar, R. and Rasgon, N. and Ratta-apha, W. and Ratzenhofer, M. and Redahan, M. and Reddy, M.S. and Reif, A. and Reininghaus, E.Z. and Richards, J.G. and Ritter, P. and Rybakowski, J.K. and Sathyaputri, L. and Scippa, Â.M. and Simhandl, C. and Severus, E. and Smith, D. and Smith, J. and Stackhouse, P.W., Jr. and Stein, D.J. and Stilwell, K. and Strejilevich, S. and Su, K.-P. and Subramaniam, M. and Sulaiman, A.H. and Suominen, K. and Tanra, A.J. and Tatebayashi, Y. and Teh, W.L. and Tondo, L. and Torrent, C. and Tuinstra, D. and Uchida, T. and Vaaler, A.E. and Veeh, J. and Vieta, E. and Viswanath, B. and Yoldi-Negrete, M. and Yalcinkaya, O.K. and Young, A.H. and Zgueb, Y. and Whybrow, P.C.",
    journal = "International Journal of Bipolar Disorders",
    year = "2021",
    volume = "9",
    number = "1",
    publisher = "Springer Science and Business Media Deutschland GmbH",
    issn = "2194-7511",
    doi = "10.1186/s40345-021-00231-7",
    keywords = "adult;  Article;  bipolar I disorder;  circadian rhythm;  exploratory research;  female;  human;  illumination;  information processing;  major clinical study;  male;  psychiatry;  seasonal variation;  statistical significance;  substance abuse;  suicide attempt;  sunlight",
    abstract = "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. © 2021, The Author(s)."
}