Fountoulakis et al. Ann Gen Psychiatry (2016) 15:19 DOI 10.1186/s12991-016-0106-2 PRIMARY RESEARCH Annals of General Psychiatry Open Access Relationship of suicide rates with climate and economic variables in Europe during 2000– 2012 Konstantinos N. Fountoulakis1*, Isaia Chatzikosta2, Konstantinos Pastiadis3, Prodromos Zanis4, Wolfram Kawohl5, Ad J. F. M. Kerkhof6, Alvydas Navickas7, Cyril Höschl8, Dusica Lecic‑Tosevski9, Eliot Sorel10, Elmars Rancans11, Eva Palova12, Georg Juckel13, Goran Isacsson14, Helena Korosec Jagodic15, Ileana Botezat‑Antonescu16, Janusz Rybakowski17, Jean Michel Azorin18, John Cookson19, John Waddington20, Peter Pregelj21, Koen Demyttenaere22, Luchezar G. Hranov23, Lidija Injac Stevovic24, Lucas Pezawas25, Marc Adida18, Maria Luisa Figuera26, Miro Jakovljević27, Monica Vichi28, Giulio Perugi29,30, Ole A. Andreassen31,32, Olivera Vukovic33, Paraskevi Mavrogiorgou13, Peeter Varnik34, Peter Dome35,36, Petr Winkler8, Raimo K. R. Salokangas37, Tiina From37, Vita Danileviciute7, Xenia Gonda35,36,38,39, Zoltan Rihmer35,36, Jonas Forsman14, Anne Grady20, Thomas Hyphantis40, Ingrid Dieset31,32, Susan Soendergaard41, Maurizio Pompili42 and Per Bech41 Abstract Background: It is well known that suicidal rates vary considerably among European countries and the reasons for this are unknown, although several theories have been proposed. The efect of economic variables has been exten‑ sively studied but not that of climate. Methods: Data from 29 European countries covering the years 2000–2012 and concerning male and female stand‑ ardized suicidal rates (according to WHO), economic variables (according World Bank) and climate variables were gathered. The statistical analysis included cluster and principal component analysis and categorical regression. Results: The derived models explained 62.4 % of the variability of male suicidal rates. Economic variables alone explained 26.9 % and climate variables 37.6 %. For females, the respective igures were 41.7, 11.5 and 28.1 %. Male suicides correlated with high unemployment rate in the frame of high growth rate and high inlation and low GDP per capita, while female suicides correlated negatively with inlation. Both male and female suicides correlated with low temperature. Discussion: The current study reports that the climatic efect (cold climate) is stronger than the economic one, but both are present. It seems that in Europe suicidality follows the climate/temperature cline which interestingly is not from south to north but from south to north‑east. This raises concerns that climate change could lead to an increase in suicide rates. The current study is essentially the irst successful attempt to explain the diferences across countries in Europe; however, it is an observational analysis based on aggregate data and thus there is a lack of control for confounders. Keywords: Suicide, Europe, Austerity, Climate *Correspondence: kfount@med.auth.gr 1 3rd Department of Psychiatry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece Full list of author information is available at the end of the article © 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Fountoulakis et al. Ann Gen Psychiatry (2016) 15:19 Background Especially after the 2008 global economic crisis, several authors expressed concern on the efect of austerity on healthcare and especially on suicidality. It is widely believed that crises of this kind increase suicides [1–7], with men of working age being at the highest risk. here are several studies published until now, suggesting the presence of such a pattern concerning the impact of the economic crisis in European countries [6, 8–18], Asia [19, 20] and the US [15] although diferent and more complex interpretations also exist [21–26]. Our multinational workgroup has published on the relationship of unstandardized suicidal rates with economic factors [26] and the current study constitutes an efort to investigate the efect of climate factors and their possible interplay with economic ones in Europe. It is well known that suicidal rates vary considerably among European countries (Fig. 1) and the reasons for this are unknown although several theories have been proposed. he efect of climate has previously been discussed but has not been investigated in a systematic way across countries. Methods Data were gathered from 29 European countries for the years 2000–2012. hey included male and female standardized suicidal rates (according to WHO), economic variables according to the World Bank (http://data. worldbank.org/) and climate variables which were calculated from the daily E-OBS gridded dataset with a spatial resolution of 0.22 degree on a rotated grid which is based on observational data. A detail description of the methodology in the gathering of data, a list of variables used and the respected deinitions are described in Additional ile 1, while the entire dataset which was used in the current study is shown in Table A. he statistical analysis included cluster analysis of variables (separately for economic and climate variables) and principal component analysis to identify prominent variables to be used afterwards in a categorical regression to test for the relationship of suicidal rates (dependent variables—DV) with economic and climate components (independent variables—IV). he method and the procedure of the statistical analyses are shown in details in Additional ile 1. Results For males, the regression analysis (see Additional ile 1 for details) returned an R = 0.790 and R-square = 0.624 (adjusted R2 = 0.602) with a standard error of estimate equal to 0.376. his model explained 62.4 % of the variability of observed male suicidal rates with the combination of all the available variables. Economic variables Page 2 of 6 alone could explain up to 26.9 % and climate variables alone up to 37.6 %. For females, the results of a similar analysis returned an R = 0.645 and R-square = 0.417 (adjusted R2 = 0.391) with a standard error of estimate equals to 0.583. his model explained 41.7 % of the variability of observed female suicide rates with the combination of all the available variables. Economic variables alone could explain up to 11.5 % and climate variables alone up to 28.1 %. hese models had very good predictive validity and itted the data well. he interaction of economic variables (see Additional ile 1) suggests that male suicides correlate with high unemployment rate in the frame of high growth rate and high inlation and low GDP per capita, while female suicides correlate negatively with inlation. Both male and female suicides correlate with low temperature both maximum and minimum (overall cold climate). All the detailed results can be found in the accompanying Additional ile 1. Discussion he current study reports that both economic and climatic variables are strongly correlated with suicide rates and can explain much of the variability observed across the European continent especially in males. he novel contribution of the current study, which is the irst one to investigate these variables together in a single model, is that the climatic efect is stronger than the economic one. Together they explain 62.4 % of male and 41.7 % of female suicide rate variability across the continent. One of the biggest enigmas is the marked geographic variability in suicide rates found in Europe, with the highest rates being found in Eastern Europe and the lowest in the Mediterranean region (Fig. 1) [26–28]. Reasons for these great diferences between national/ regional suicide rates have not been fully explained yet. Geographic (latitude, longitude, altitude) climatic, dietary, genetic, economic, religious and other sociocultural diferences can be taken into account, but an additional problem is that there is probably an intercorrelation between them. However, the diferences in the psychiatric morbidity (including alcohol abuse), as well as the accuracy of the registration of suicide, the stigma associated with mental illness and suicide (possibly inluencing help-seeking behaviour and reporting rates), the availability of lethal methods, and the availability and quality of the social/health care systems should also be considered [27, 29]. he link between economic variables and suicidality has been the focus of extensive research in the past although a clear cause and efect relationship has not been solidly established because the temporal Fountoulakis et al. Ann Gen Psychiatry (2016) 15:19 Fig. 1 Map of male and female standardized suicide rates in Europe relationship suggests that suicide rate increase precedes the increase in unemployment and other variables which indicate recession [25, 30]. In contrast, the literature on the efect of climate is limited. While there are no reports correlating diferences in suicides with diferences in climate between countries and regions of the world, there is a signiicant literature concerning the seasonal pattern of suicides and suicide attempts. he data are complex and a number of confounding variables exist, including gender, social cues and diagnosis [31–39]. Page 3 of 6 he literature suggests that overall the suicide rate is higher in autumn [40] but also during the summer with the lowest observed during winter [41–44]. Other papers report higher rates during spring and summer [45–47] or spring and autumn [48] or only spring [49–53]. here is a positive linear relation between the variation in suicide rate and geographic latitude [54], and this is true for both hemispheres but not for the tropical zone where there seems to be no seasonal pattern [55–57]. On the contrary, seasonality seems to be more pronounced in those countries closer to the poles [41] and seems to correlate with male gender and violent methods [51, 52, 58, 59] as well as with the traditional agricultural societies [50, 58]. However, some authors did not ind any seasonality concerning the methods used [40]. he irst ever study on the efect of climate on suicides reported that falling barometric pressure was correlated with increasing suicides [60] but this was not conirmed by latter studies. Most reports suggest that the suicide rates are higher during periods of high temperature [47– 49, 51, 52, 61–73], low rainfalls [47, 63, 72, 74, 75] and more sunshine [41, 44, 45, 61, 68, 70, 76–78]. It is interesting that it seems the temperature efect is so strong that it exerts its efect on the same day concerning suicides by a violent method [51, 52] or a day after [66]. In contrast with the above, one paper reported a positive correlation of rainfalls with increasing suicidal rates [68] and another one no efect of temperature [79]. In Italy, the distribution of deaths by suicide shows a negative relationship with mean yearly temperature values, max and min, and with sun exposure indicators, and a positive, but less signiicant relationship with rainfall values [75]. For females, the links between temperature and suicides are less consistent than for males, and sometimes have a reverse sign, too [65]. A negative correlation for temperature has also been reported from Taiwan [76]. Although the irst ever study reported that falling barometric pressure was correlated with increasing suicides [60], one more recent study conirmed this by reporting that cloudiness and atmospheric pressure were negatively correlated [47] but another study reported the opposite [73]. It has been reported that in Kazakhstan, an increase in the mean apparent temperature by 1 degree Celsius was associated with an increase in suicide counts by 2.1 % [69] and temperature variability explains more than 60 % of the total suicide variance [71]. Overall, the climatic variables explain 63 % of suicides [75]. he current study suggests that in countries with cold climate, suicidality is higher, and this should be considered in combination with the known seasonality of suicides which is not, however, part of the present paper. It seems that in Europe, suicidality follows the climate/temperature cline which interestingly is not from south to north but from south to north-east. Fountoulakis et al. Ann Gen Psychiatry (2016) 15:19 Although most reports suggest that sociodemographical factors are stronger predictors in comparison to climate and seasonality [64, 80], there are opposite reports [72]. Our results suggest that climatic variables could be more important factors than socio-economic ones. Since meteorological variables seem to have an impact on mental health, there are concerns that climate change could lead to an increase in the rates of mental disorders and especially addictions and suicide rates [81]. However, this is highly unlikely to explain the high impact on suicidality from rather benign increases in temperature. It seems also that extended periods of light in the summer may contribute to impulsive–aggressive summer suicides [41], while abrupt temperature changes twice a year seem to trigger the activity in brown adipose tissue and deepen depression [48]. In this frame sunshine, via interactions with serotonin neurotransmission, may trigger increased impulsivity and promote suicidal acts [78]. he current study is the irst successful attempt to explain the large diferences between European countries in terms of suicidal rates. It also suggests the presence of diferent underlying mechanisms for males and females pertaining to the interaction with diferent qualities of environmental stimuli. However, it sufers from a number of limitations. It is an observational analysis based on aggregate data collected from national statistical agencies. hus, there is a lack of ability to deeper investigation and understanding of the structure. Probably, there are diferences between countries both in the quality of the data as well as in the level of misclassiication of suicide, and these could lead to potential bias between countries [82], but it is not expected they had a signiicant impact on the results of the current study. Cross-level bias and aggregation bias are typical of studies similar to the current one [83]. he efects observed on the aggregate level might be modulated by the ecological context at the level of the individual person [84]. Also time series data are frequently non-stationary and vulnerable to random indings [84]. Finally, another source of bias is the possible registration bias concerning suicides between countries and over time, and also concerning the quality of the economical statistics. he authors chose to publish the full database their analysis was based on in an appendix, since they strongly believe that this database should be publicly available, so that anyone could perform further analysis which is one of the major contributions of the current study. Conclusions he current study reports that both economic and climatic variables are strongly correlated with suicide rates and can explain much of the variability observed across Page 4 of 6 the European continent especially in males. However, the climatic efect is stronger than the economic one concerning both sexes, but the relative efect of climate in comparison to economic variables was higher for females (ratio climate to economy efect: 2.44 in females vs. 1.39 in males). Together they explain 62.4 % of male and 41.7 % of female suicide rate variability across the continent. Additional ile Additional ile 1. Web appendix. Authors’ contributions All authors had equal contribution in the overall production of the current article. KNF and KP had the idea for the study and designed the study with input from all other co‑authors. PZ provided the climate data. KNF was respon‑ sible for inalizing the database, while KP did the statistical analysis, with input from all co‑authors. KNF wrote the irst draft and all authors contributed to successive drafts. All authors had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. All authors read and approved the inal manuscript. Author details 1 3rd Department of Psychiatry, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece. 2 Aristotle University of Thessaloniki, Thes‑ saloniki, Greece. 3 Department of Music Studies, School of Fine Arts, Aristotle University of Thessaloniki, Thessaloniki, Greece. 4 Department of Meteorol‑ ogy and Climatology, School of Geology, Aristotle University of Thessaloniki, Thessaloniki, Greece. 5 Department of Psychiatry, Psychotherapy and Psycho‑ somatics, Center for Social Psychiatry, University Hospital of Psychiatry, Zurich, Switzerland. 6 Department of Clinical Psychology, Faculty of Psychology and Education, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands. 7 Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania. 8 National Institute of Mental Health, Kle‑ cany, Czech Republic. 9 Institute of Mental Health, WHO Collaborating Centre, Palmoticeva 37, 11000 Belgrade, Serbia. 10 The George Washington University, School of Medicine & School of Public Health, Washington, DC, USA. 11 Depart‑ ment of Psychiatry and Narcology, Riga Stradins University, Tvaika Str. 2, Riga, LV 1005, Latvia. 12 Department of Psychiatry, University Hospital, SNP 1, 040 66 Košice, Slovakia. 13 Department of Psychiatry, Ruhr University Bochum, LWL‑ University Hospital, Alexandrinenstr.1, 44791 Bochum, Germany. 14 Depart‑ ment of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden. 15 Psychiat‑ ric Hospital Vojnik, Celjska Cesta 37, Vojnik, Slovenia. 16 National Mental Health Center and Anti‑drug, Bucharest, Romania. 17 Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland. 18 Department of Psy‑ chiatry, Sainte Marguerite Hospital, 13274 Marseille, France. 19 East London NHS Trust, London E1 4DG, UK. 20 Molecular & Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin 2, Ireland. 21 University Psychiatric Hos‑ pital, Ljubljana, Slovenia. 22 University Psychiatric Center KU Leuven, Louvain, Belgium. 23 Second Psychiatric Clinic, University Hospital for Active Treatment in Neurology and Psychiatry “Sveti Naum”, Soia, Bulgaria. 24 Psychiatric Clinic, Clinical Center of Montenegro, School of Medicine, University of Montene‑ gro, Podgorica, Montenegro. 25 Division of Biological Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria. 26 Faculty of Medicine, University of Lisbon, Av. Prof. Egas Moniz, 1649‑035 Lis‑ bon, Portugal. 27 Department of Psychiatry, University Hospital Center Zagreb, Zagreb, Croatia. 28 Centre for Epidemiology, Surveillance and Health Promo‑ tion (CNESPS), National Institute of Health (ISS), Rome, Italy. 29 Psychiatry Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy. 30 Institute of Behavioral Sciences “G. De Lisio”, Pisa, Italy. 31 NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway. 32 Division of Mental Health and Addiction, Oslo Univer‑ sity Hospital, Oslo, Norway. 33 Institute of Mental Health, School of Medicine, University of Belgrade, Belgrade, Serbia. 34 Estonian‑Swedish Mental Health Fountoulakis et al. Ann Gen Psychiatry (2016) 15:19 and Suicidology Institute, Tallinn, Estonia. 35 Department of Clinical and Theo‑ retical Mental Health, Faculty of Medicine, Semmelweis University, Budapest, Hungary. 36 Laboratory for Suicide Research and Prevention, National Institute of Psychiatry and Addictions, Budapest, Hungary. 37 Department of Psychia‑ try, University of Turku, Turku, Finland. 38 Department of Pharmacodynamics, MTA‑SE, Semmelweis University, Budapest, Hungary. 39 Neuropsychopharma‑ cology and Neurochemistry Research Group, Hungarian Academy of Sciences, Budapest, Hungary. 40 Department of Psychiatry, Ioannina School of Medicine, Ioannina, Greece. 41 Psychiatric Research Unit, Mental Health Centre North Zealand, University of Copenhagen, Dyrehavevej 48, 3400 Hillerød, Denmark. 42 Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy. Acknowledgements The authors wish to dedicate this paper to the memory of Juan‑Lopez Ibor, originally the leader of this workgroup and the initiative. Competing interests The authors declare that they have no competing interests. Funding This research received no speciic grant from any funding agency in the public, commercial, or not‑for‑proit sectors. Peter Dome and Xenia Gonda are recipients of the Janos Bolyai Fellowship of the Hungarian Academy of Sciences. Received: 2 June 2016 Accepted: 22 July 2016 References 1. World Health Organization. Financial crisis and global health: report of a high‑level consultation. Geneva: WHO; 2009. 2. Swinscow D. Some suicide statistics. Br Med J. 1951;1(4720):1417–23. 3. Milner A, Page A, LaMontagne AD. Duration of unemployment and sui‑ cide in Australia over the period 1985–2006: an ecological investigation by sex and age during rising versus declining national unemployment rates. J Epidemiol Community Health. 2013;67(3):237–44. 4. 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