Michael BauerTasha GlennEric D. AchtyesMartin AldaEsen AgaogluKürşat AltınbaşOle A. AndreassenElias AngelopoulosRaffaella ArdauEdgar Arrua VaresMemduha AydinYavuz AyhanChristopher BaethgeRita BauerBernhard T. BauneCeylan BalabanClaudia Becerra-PalarsAniruddh P. BeherePrakash B. BehereHabte BeleteTilahun BeleteGabriel Okawa BelizarioFrank BellivierRobert H. BelmakerFrancesco BenedettiMichael BerkYuly BersudskyŞule BicakciHarriet Birabwa-OketchoThomas D. BjellaConan BradyJorge CabreraMarco CappucciatiAngela Marianne Paredes CastroWei Ling ChenEric Y.Wo CheungSilvia ChiesaMarie CroweAlessandro CuomoSara DallaspeziaMaria Del ZompoPratikkumar DesaiSeetal DoddMarkus DonixBruno EtainAndrea FagioliniFrederike T. FellendorfEwa Ferensztajn-RochowiakJess G. FiedorowiczKostas N. FountoulakisMark A. FryePierre A. GeoffroyAna Gonzalez-PintoJohn F. GottliebPaul GrofBartholomeus C.M. HaarmanHirohiko HarimaMathias Hasse-SousaChantal HenryLone HøffdingJosselin HouenouMassimiliano ImbesiErkki T. IsometsäMaja IvkovicSven JannoSimon JohnsenFlávio KapczinskiGregory N. KarakatsoulisMathias KardellLars Vedel KessingSeong Jae KimBarbara KönigTimur L. KotMichael KovalMauricio KunzBeny LaferMikael LandénErik R. LarsenMelanie LengerUte LewitzkaRasmus W. LichtCarlos Lopez-JaramilloAlan MacKenzieHelle Østergaard MadsenSimone Alberte Kongstad A. MadsenJayant MahadevanAgustine MahardikaMirko ManchiaWendy MarshMonica Martinez-CengotitabengoaKlaus MartinyYuki MashimaDeclan M. McLoughlinYbe MeestersIngrid MelleFátima Meza-UrzúaMok Yee MingScott MonteithMuthukumaran MoorthyGunnar MorkenInstituto de Investigación Sanitaria BioarabaFaculty of Health SciencesUniversitätsklinikum Carl Gustav Carus DresdenUniversité Paris CitéCentre for Youth Mental HealthMelbourne Medical SchoolAzienda Ospedaliero Universitaria di CagliariUniversite Paris-SaclayOslo UniversitetssykehusNational Institute for Health and WelfareMSU College of Human MedicineDatta Meghe Institute of Medical Sciences (Deemed to be University)Baskent University Faculty of MedicineBahar Dar UniversityKlinicki Centar SrbijePoznan University of Medical SciencesTartu ÜlikoolUniversidad de AntioquiaUniversità degli Studi di CagliariMichigan State UniversityUniversity of OttawaUniversidad del Pais VascoSahlgrenska AkademinBen-Gurion University of the NegevUniversity of MelbourneKeio University School of MedicineUniversité Paris-Est CréteilUniversity of CologneDalhousie University, Faculty of MedicineIRCCS Ospedale San RaffaeleUniversitetssykehuset i TrondheimHôpital Bichat-Claude-Bernard AP-HPTokyo Metropolitan Matsuzawa HospitalAalborg UniversityHacettepe ÜniversitesiSyddansk UniversitetDeakin UniversityUniversity of TorontoNational Institute of Mental Health and Neuro SciencesAalborg UniversitetshospitalDipartimento di Scienze Mediche, Chirurgiche e NeuroscienzeCopenhagen University HospitalSelçuk Tip FakültesiNorthwestern University Feinberg School of MedicineNorges Teknisk-Naturvitenskapelige UniversitetKarolinska InstitutetTrinity College DublinUniversità Vita-Salute San RaffaeleSingapore Institute of Mental HealthUniversitätsklinikum FrankfurtUniversity of Southern Denmark, EsbjergUniversidade de São PauloEginition HospitalUniversidade Federal do Rio Grande do SulRigshospitaletMedizinische Universität GrazVeterans General Hospital-Taichung TaiwanUniversitair Medisch Centrum GroningenMayo ClinicHelsingin YliopistoUniversity of Otago, ChristchurchInstituto Nacional de Psiquiatría Ramon de la FuenteUniversity of GlasgowUniversity of Massachusetts Chan Medical SchoolWestfälische Wilhelms-Universität MünsterPrivate PracticeGHU Paris Psychiatrie et NeurosciencesMataram UniversityKhanty-Mansiysk Clinical Psychoneurological HospitalGroupe hospitalier universitaire Paris psychiatrie et neurosciencesChronoRecord AssociationBIPOLAR Zentrum Wiener NeustadtJosé Horwitz Psychiatric InstituteCheongjuButabika HospitalPine Rest Christian Mental Health Services2022-08-042022-08-042021-12-01International Journal of Bipolar Disorders. Vol.9, No.1 (2021)219475112-s2.0-85114003020https://repository.li.mahidol.ac.th/handle/20.500.14594/77542Background: 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.Mahidol UniversityMedicineNeuroscienceArticleSCOPUS10.1186/s40345-021-00231-7