Association of weekly suicide rates with temperature anomalies in two different climate types.
Annual suicide deaths outnumber the total deaths from homicide and war combined. Suicide is a complex behavioral endpoint, and a simple cause-and-effect model seems highly unlikely, but relationships with weather could yield important insight into the biopsychosocial mechanisms involved in suicide deaths. This study has been designed to test for a relationship between air temperature and suicide frequency that is consistent enough to offer some predictive abilities. Weekly suicide death totals and anomalies from Toronto, Ontario, Canada (1986-2009) and Jackson, Mississippi, USA (1980-2006) are analyzed for relationships by using temperature anomaly data and a distributed lag nonlinear model. For both analysis methods, anomalously cool weeks show low probabilities of experiencing high-end suicide totals while warmer weeks are more likely to experience high-end suicide totals. This result is consistent for Toronto and Jackson. Weekly suicide totals demonstrate a sufficient association with temperature anomalies to allow some prediction of weeks with or without increased suicide frequency. While this finding alone is unlikely to have immediate clinical implications, these results are an important step toward clarifying the biopsychosocial mechanisms of suicidal behavior through a more nuanced understanding of the relationship between temperature and suicide.
Department of Geosciences, Fort Hays State University, Hays, KS 67601, USA. pgdixon@fhsu.edu.
P Grady
PG
Dixon
Sunnybrook Health Sciences Centre, Department of Psychiatry, University of Toronto, Toronto, ON M4N 3M5, Canada. mark.sinyor@sunnybrook.ca.
Mark
M
Sinyor
Sunnybrook Health Sciences Centre, Department of Psychiatry, University of Toronto, Toronto, ON M4N 3M5, Canada. ayal.schaffer@sunnybrook.ca.
Ayal
A
Schaffer
Sunnybrook Health Sciences Centre, Department of Psychiatry, University of Toronto, Toronto, ON M4N 3M5, Canada. anthony.levitt@sunnybrook.ca.
Anthony
A
Levitt
Department of Geosciences, Mississippi State University, Mississippi State, MS 39762, USA. meloche@geosci.msstate.edu.
Christa R
CR
Haney
Department of Geography, University of Tennessee, Knoxville, TN 37996, USA. ellis@utk.edu.
Kelsey N
KN
Ellis
Department of Geography, Kent State University, Kent, OH 44242, USA. ssherid1@kent.edu.
Scott C
SC
Sheridan
D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008922:Mississippi; D009864:Ontario; D012621:Seasons; D013405:Suicide / Q000706:statistics & numerical data; D014887:Weather