Abstract
The effect of environmental temperature on suicide risk is an important issue given the increase in global temperatures expected over the following century. Previous research has produced conflicting findings: Studies concerned with temporal variation in temperature and suicide have tended to find a positive relationship, while those concerned with geographical variation in temperature and suicide have tended to find a negative relationship. In this study, we aimed firstly to estimate the relationship between suicide incidence and three components of variation in temperature: Irregular, seasonal, and geographical. Secondly, we aimed to critically examine what this information can (and cannot) tell us about the likely effects of anthropogenic climate change on suicide rates. Suicide data from New Zealand for the period 1988 to 2007 were collated according to date of death and district and compared with temperature data from the same period. Using generalized linear mixed models, we found that irregular variation in temperature was positively related to suicide incidence, with about 1.8 % more suicides for every 1 °C increase in temperature. On the other hand, seasonal variation in temperature had virtually no linear relationship with suicide incidence, and when controlling for demographic differences, geographical variation in temperature was negatively related to suicide incidence. We conclude that differences in both the sign and the direction of the effects of different forms of variation in temperature mean that it is very difficult to predict how climate change will affect risk of suicide.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ajdacic-Gross V, Lauber C, Sansossio R et al (2007) Seasonal associations between weather conditions and suicide—evidence against a classic hypothesis. Am J Epidemiol 165:561–569. doi:10.1093/aje/kwk034
Ajdacic-Gross V, Bopp M, Ring M et al (2010) Seasonality in suicide – a review and search of new concepts for explaining the heterogeneous phenomena. Soc Sci Med 71:657–666. doi:10.1016/j.socscimed.2010.05.030
Bates D, Maechler M, Bolker B, Walker S (2013) lme4: Linear mixed-effects models using Eigen and S4. http://cran.r-project.org/web/packages/lme4/index.html
Chew KSY, McCleary R (1995) The spring peak in suicides: a cross-national analysis. Soc Sci Med 40:223–230. doi:10.1016/0277-9536(94)E0070-9
R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org/
Deisenhammer EA (2003) Weather and suicide: the present state of knowledge on the association of meteorological factors with suicidal behaviour. Acta Psychiatr Scand 108:402–409. doi:10.1046/j.0001-690X.2003.00209.x
Dixon PG, Kalkstein AJ (2009) Climate suicide relationships: a research problem in need of geographic methods and cross-disciplinary perspectives. Geogr Compass 3:1961–1974. doi:10.1111/j.1749-8198.2009.00286.x
Dixon PG, Sinyor M, Schaffer A et al (2014) Association of weekly suicide rates with temperature anomalies in two different climate types. Int J Environ Res Public Health 11:11627–11644. doi:10.3390/ijerph111111627
Durkheim É (1897) Le Suicide. France, Léo, Paris
Grove O, Lynge J (1979) Suicide and attempted suicide in Greenland. Acta Psychiatr Scand 60:375–391. doi:10.1111/j.1600-0447.1979.tb00286.x
Holopainen J, Helama S, Björkenstam C, Partonen T (2013) Variation and seasonal patterns of suicide mortality in Finland and Sweden since the 1750s. Environ Health Prev Med 18:494–501. doi:10.1007/s12199-013-0348-4
Holopainen J, Helama S, Partonen T (2014) Does diurnal temperature range influence seasonal suicide mortality? Assessment of daily data of the Helsinki metropolitan area from 1973 to 2010. Int J Biometeorol 58:1039–1045. doi:10.1007/s00484-013-0689-0
Hsiang SM (2013) Visually-weighted regression. http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2265501
Kim Y, Kim H, Kim D-S (2011) Association between daily environmental temperature and suicide mortality in Korea (2001–2005). Psychiatry Res 186:390–396. doi:10.1016/j.psychres.2010.08.006
Lester D (1999) Climatic data and national suicide and homicide rates. Percept Mot Skills 89:1036. doi:10.2466/pms.1999.89.3.1036
Likhvar V, Honda Y, Ono M (2011) Relation between temperature and suicide mortality in Japan in the presence of other confounding factors using time-series analysis with a semiparametric approach. Environ Health Prev Med 16:36–43. doi:10.1007/s12199-010-0163-0
Maes M, Meyer F, Thompson P et al (1994) Synchronized annual rhythms in violent suicide rate, ambient temperature and the light–dark span. Acta Psychiatr Scand 90:391–396. doi:10.1111/j.1600-0447.1994.tb01612.x
Maes M, Scharpe S, Verkerk R et al (1995) Seasonal variation in plasma L-tryptophan availability in healthy volunteers: relationships to violent suicide occurrence. Arch Gen Psychiatry 52:937–946. doi:10.1001/archpsyc.1995.03950230051008
Müller H, Biermann T, Renk S et al (2011) Higher environmental temperature and global radiation are correlated with increasing suicidality—a localized data analysis. Chronobiol Int 28:949–957. doi:10.3109/07420528.2011.618418
Nie Z, Racine JS (2012) The crs package: nonparametric regression splines for continuous and categorical predictors. R J 12:48–56
Page LA, Hajat S, Kovats R (2007) Relationship between daily suicide counts and temperature in England and Wales. Br J Psychiatry 191:106–112. doi:10.1192/bjp.bp.106.031948
Preti A (1997) The influence of seasonal change on suicidal behaviour in Italy. J Affect Disord 44:123–130. doi:10.1016/S0165-0327(97)00035-9
Preti A (1998) The influence of climate on suicidal behaviour in Italy. Psychiatry Res 78:9–19. doi:10.1016/S0165-1781(97)00154-6
Preti A, Lentini G, Maugeri M (2007) Global warming possibly linked to an enhanced risk of suicide: data from Italy, 1974–2003. J Affect Disord 102:19–25. doi:10.1016/j.jad.2006.12.003
Qi X, Tong S, Hu W (2009) Preliminary spatiotemporal analysis of the association between socio-environmental factors and suicide. Environ Health. doi:10.1186/1476-069X-8-46
Robbins MC, Dewalt BR, Pelto PJ (1972) Climate and behavior: a biocultural study. J Cross-Cult Psychol 3:331–344. doi:10.1177/002202217200300402
Rotton J (1986) Determinism redux: climate and cultural correlates of violence. Environ Behav 18:346–368. doi:10.1177/0013916586183003
Ruuhela R, Hiltunen L, Venäläinen A et al (2008) Climate impact on suicide rates in Finland from 1971 to 2003. Int J Biometeorol 53:167–175. doi:10.1007/s00484-008-0200-5
Schönbrodt F (2012) Visually weighted regression in R (à la Solomon Hsiang). http://www.nicebread.de/visually-weighted-regression-in-r-a-la-solomon-hsiang/
Souêtre E, Wehr TA, Douillet P, Darcourt G (1990) Influence of environmental factors on suicidal behavior. Psychiatry Res 32:253–263. doi:10.1016/0165-1781(90)90030-9
Statistics New Zealand (2013) Subnational population estimates tables. http://www.stats.govt.nz/browse_for_stats/population/estimates_and_projections/subnational-pop-estimates-tables.aspx. Accessed 30 May 2014
Törő K, Dunay G, Bartholy J et al (2009) Relationship between suicidal cases and meteorological conditions. J Forensic Leg Med 16:277–279. doi:10.1016/j.jflm.2008.12.015
Vyssoki B, Praschak-Rieder N, Sonneck G et al (2012) Effects of sunshine on suicide rates. Compr Psychiatry 53:535–539. doi:10.1016/j.comppsych.2011.06.003
Wang X-F (2010) fANCOVA: Nonparametric Analysis of Covariance.
Yan YY (2000) Geophysical variables and behavior: LXXXXIX. The influence of weather on suicide in Hong Kong. Percept Mot Skills 91:571–577. doi:10.2466/pms.2000.91.2.571
Yang AC, Tsai S-J, Huang NE (2011) Decomposing the association of completed suicide with air pollution, weather, and unemployment data at different time scales. J Affect Disord 129:275–281. doi:10.1016/j.jad.2010.08.010
Yip PSF, Chao A, Ho TP (1998) A re-examination of seasonal variation in suicides in Australia and New Zealand. J Affect Disord 47:141–150. doi:10.1016/S0165-0327(97)00135-3
Zung WWK, Green RL (1974) Seasonal variation of suicide and depression. Arch Gen Psychiatry 30:89–91. doi:10.1001/archpsyc.1974.01760070067010
Acknowledgments
We thank Jane Perrott and Chris Lewis at the Ministry of Health for providing suicide mortality data, Richard Speirs at Statistics New Zealand for providing population data, and two anonymous reviewers for helpful feedback.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
ESM 1
(DOCX 45 kb)
Rights and permissions
About this article
Cite this article
Williams, M.N., Hill, S.R. & Spicer, J. Will climate change increase or decrease suicide rates? The differing effects of geographical, seasonal, and irregular variation in temperature on suicide incidence. Climatic Change 130, 519–528 (2015). https://doi.org/10.1007/s10584-015-1371-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10584-015-1371-9