Seasonal Variation of Suicide in Brazil

Abstract

Most of what is known about the seasonal variation in suicide rate originates from studies conducted in the northern hemisphere; very few studies have been done in the southern hemisphere. The purpose of the present study was to explore the possibility that in Brazil, the seasonal variation of suicides is a function of photoperiod. This was accomplished by analyzing monthly suicide data for a 12 yr period (1979 to 1990), within latitudes ranging from 2 degrees N to 33 degrees S. Single cosinor analyses with periods of 12 or 6 months were applied to time series of monthly total and suicidal deaths, separated by gender and state. Significant spring or early summer peaks of suicide were found only in the south of Brazil for both men and women, except for the latter in one state. These peaks did not coincide with those found for total deaths, which occurred in the autumn or winter in all areas. No significant six-month period was found. In the present study, the chance of a suicide was typically 10-17% higher during the peak period than during the other months of the year. Although this moderate seasonal effect might not be sufficient to justify planning large scale prophylactic interventions, those dealing with patients who have suicide ideation should be aware of this high risk time.

Seasonality of suicide in the city of Sao Paulo, Brazil, 1979-2003

“…For the State of São Paulo and other regions, no identifiable seasonal annual pattern was evident. 17 The findings of the present study were in line with those from studies of the temperate zone in the Northern hemisphere and suggest that suicide seasonality is linked only to localities situated in the climatic temperate zone, where the four seasons of the year are quite distinct. The States of Paraná, Santa Catarina and Rio Grande do Sul are situated in the temperate zone of the globe, since they are South of the Tropic of Capricorn.…”

“…The States of Paraná, Santa Catarina and Rio Grande do Sul are situated in the temperate zone of the globe, since they are South of the Tropic of Capricorn. The difference observed between the results presented by Benedito-Silva et al 17 and the present study might be explained by methodological differences. However, the result of a seasonality trend observed in the male sample might reinforce the hypothesis that suicide seasonality depends on the latitude of the studied region, with intermediate results in tropical regions, as was observed by our study in the city of São Paulo.…”

Conducta suicida en niños y adolescentes ingresados en un hospital general: Análisis descriptivo

“…Por otro lado, un aspecto pobremente estudiado respecto a la conducta suicida en niños y adolescentes es su incidencia en las diferentes épocas del año o estacionalidad. Estudios en población adulta sobre el tema, asocian el patrón estacional del suicidio a la presencia de psicopatología, trastornos del ánimo, latitud, género y letalidad, entre otros [16][17][18][19] . En Chile, Heerlein et al muestran la existencia de un peak primaveral en suicidio en ambos sexos, en función del fotoperíodo 20 .…”

Suicide and meteorological factors in São Paulo, Brazil, 1996-2011: a time series analysis

“…[13][14][15] Since then, review studies, most performed in the Northern Hemisphere in mid-latitudes and developed nations, have continued to describe this pattern. 7,8 In Brazil, Benedito-Silva et al 16 found a seasonal distribution of suicide, peaking in spring/summer, but only in the southern states. Specifically in the city of São Paulo, Bando and Volpe reported a significant circannual cycle peaking in spring/summer for both men and women from 1996 to 2010, 17 while Nejar et al 18 did not find seasonality or any association between suicide and meteorological factors in São Paulo from 1996 to 2004.…”