BACKGROUND: Recent research has corroborated the notion that seasonality in suicide is more heterogeneous and less consistent than postulated by former scholars. This work investigates the smoothing out of suicide seasonality in Switzerland between the late 19th and the end of the 20th century. It includes analyses by region and by suicide method. METHODS: Monthly suicide frequencies in Switzerland are available for the period 1876-2000. Data on canton/region are available for the periods 1901-1920 and 1969-2000, and data on suicide method for the periods 1881-1920 and 1969-2000. Analyses focusing on the overall change rely on data aggregated by quinquennia. The Edwards' test and the peak-low ratio were used in univariate analyses of seasonality. Putative determinants of the peak-low ratio were examined using regression analysis with cantonal data. RESULTS: The decrease of seasonal effects in suicide applies to a period of more than 100 years in Switzerland. Big differences of seasonal effects have existed all the time with regard to specific methods and to specific regions. No seasonality was apparent in poisoning, and in Geneva and Basle City, respectively. However, the seasonal effects have been most impressive in drowning and hanging suicides, and in rural Catholic regions. In regression analysis, the decline in suicide seasonality is associated with the decline in the agricultural work force. CONCLUSIONS: The smoothing out of suicide seasonality in Switzerland has been a continuous long term process, which probably started by the end of 19th century. Seasonal effects in suicide will probably fade away in most regions of Switzerland and in most suicide methods. This process is in parallel with the disappearance of the traditional rural society.
BACKGROUND: Recent research has corroborated the notion that seasonality in suicide is more heterogeneous and less consistent than postulated by former scholars. This work investigates the smoothing out of suicide seasonality in Switzerland between the late 19th and the end of the 20th century. It includes analyses by region and by suicide method. METHODS: Monthly suicide frequencies in Switzerland are available for the period 1876-2000. Data on canton/region are available for the periods 1901-1920 and 1969-2000, and data on suicide method for the periods 1881-1920 and 1969-2000. Analyses focusing on the overall change rely on data aggregated by quinquennia. The Edwards' test and the peak-low ratio were used in univariate analyses of seasonality. Putative determinants of the peak-low ratio were examined using regression analysis with cantonal data. RESULTS: The decrease of seasonal effects in suicide applies to a period of more than 100 years in Switzerland. Big differences of seasonal effects have existed all the time with regard to specific methods and to specific regions. No seasonality was apparent in poisoning, and in Geneva and Basle City, respectively. However, the seasonal effects have been most impressive in drowning and hanging suicides, and in rural Catholic regions. In regression analysis, the decline in suicide seasonality is associated with the decline in the agricultural work force. CONCLUSIONS: The smoothing out of suicide seasonality in Switzerland has been a continuous long term process, which probably started by the end of 19th century. Seasonal effects in suicide will probably fade away in most regions of Switzerland and in most suicide methods. This process is in parallel with the disappearance of the traditional rural society.
Authors: Ingo W Nader; Jakob Pietschnig; Thomas Niederkrotenthaler; Nestor D Kapusta; Gernot Sonneck; Martin Voracek Journal: PLoS One Date: 2011-02-24 Impact factor: 3.240
Authors: Konstantinos N Fountoulakis; Isaia Chatzikosta; Konstantinos Pastiadis; Prodromos Zanis; Wolfram Kawohl; Ad J F M Kerkhof; Alvydas Navickas; Cyril Höschl; Dusica Lecic-Tosevski; Eliot Sorel; Elmars Rancans; Eva Palova; Georg Juckel; Goran Isacsson; Helena Korosec Jagodic; Ileana Botezat-Antonescu; Janusz Rybakowski; Jean Michel Azorin; John Cookson; John Waddington; Peter Pregelj; Koen Demyttenaere; Luchezar G Hranov; Lidija Injac Stevovic; Lucas Pezawas; Marc Adida; Maria Luisa Figuera; Miro Jakovljević; Monica Vichi; Giulio Perugi; Ole A Andreassen; Olivera Vukovic; Paraskevi Mavrogiorgou; Peeter Varnik; Peter Dome; Petr Winkler; Raimo K R Salokangas; Tiina From; Vita Danileviciute; Xenia Gonda; Zoltan Rihmer; Jonas Forsman; Anne Grady; Thomas Hyphantis; Ingrid Dieset; Susan Soendergaard; Maurizio Pompili; Per Bech Journal: Ann Gen Psychiatry Date: 2016-08-09 Impact factor: 3.455