Influence of environmental factors on suicidal behavior

doi:10.1016/0165-1781(90)90030-9

Psychiatry Research

Volume 32, Issue 3, June 1990, Pages 253-263

https://doi.org/10.1016/0165-1781(90)90030-9 Get rights and content

Abstract

The regional distribution of completed suicide was analyzed in 19 regions of France for the years 1975 and 1983. The regional distributions of environmental variables (ambient temperature, sunlight duration, and precipitation) and of sociological factors (social cohesion, socioeconomic status, status of women, and social support) were then correlated using Pearson coefficients, stepwise regression analysis, and partial correlations. Our main finding is that environmental factors such as ambient temperature may play a role in the regional distribution of completed suicide in France. Both the stepwise regression analysis and the controlled regression analysis revealed that, among all the variables studied (environmental and sociological), the main factors affecting the regional distribution of suicide were ambient temperature and sunlight duration. To our knowledge, this is the first detailed study demonstrating a clear relationship between environmental variables and suicidal behavior. The finding may be consistent with the recent description of forms of affective disorders occuring in relationship to environmental factors.

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Cited by (64)

The impact of daylight on suicide rates
2022, Economics and Human Biology
Since Durkheim and Morselli found a spring peak in suicides in the late 19th century, researchers have presented possible explanations, including daylight variation, for this seasonal pattern. Our identification strategy exploits the idiosyncratic variation in daylight within Norwegian regions, arising from the country’s substantial latitudinal range. We use full population data for a period of 45 years in a pre-registered research design. We find a small and non-significant relationship: One extra hour of daylight increases the suicide rate by merely 0.75 % (95 % CI: −0.4 % to 1.9 %).
Climate rather than economic variables might have caused increase in US homicide but not suicide rates during the Great Depression
2022, Psychiatry Research
Citation Excerpt :
The first ever study on the effect of climate on suicides reported that falling barometric pressure was correlated with increasing suicides (Digon and Bock, 1966) but this was not confirmed by latter studies. Most reports suggest that the suicide rates are higher during periods of high temperature (Deisenhammer et al., 2003; Dixon et al., 2014; Doganay et al., 2003; Grjibovski et al., 2013; Helama et al., 2013; Holopainen et al., 2013; Inoue et al., 2012; Ishii et al., 2013; Lee et al., 2006; Likhvar et al., 2011; Lin et al., 2008; Muller et al., 2011; Oravecz et al., 2006; Preti et al., 2007; Qi et al., 2014; Souetre et al., 1990; Tsai and Cho, 2012; Wang et al., 1997), low rainfalls (Deisenhammer et al., 2003; Doganay et al., 2003; Hanigan et al., 2012; Preti, 1998; Tsai and Cho, 2012) and more sunshine (Bjorksten et al., 2005; Bjorksten et al., 2009; Heerlein et al., 2006; Inoue et al., 2012; Lambert et al., 2003; Oravecz et al., 2006; Souetre et al., 1990; Tsai, 2010; Vyssoki et al., 2012). It is interesting that it seems the temperature effect is so strong that it exerts its effect on the same day concerning suicides by a violent method (Likhvar et al., 2011; Lin et al., 2008) or a day after (Muller et al., 2011).
It is widely believed that during the Great Depression (1929–1933) there was a rise in suicidal rates which was causally related to the increase in unemployment. There are no studies on the effect the Great Depression had on homicidal rates
The data concerning suicide, homicide, economic and climatic variables for the years 1900–1940 for the whole of the US were gathered from the US Center for Disease Control, the Maddison Project, the National Bureau of Economic Research and the National Climatic Data Center. Time Series Analysis was performed.
The results are inconclusive on the role of economic factors but preclude any role of climate on suicidal rates during the years 1900–1940 in the US. Suicidal rates might have a 24-years periodicity, however much longer time series are needed to confirm this. On the contrary they strongly suggest an effect of higher temperatures on homicidal rates after 1922.
The results of the current study suggest a direct and clear effect of climate (higher temperatures) on the increasing homicidal rates in the US after 1922 but failed to establish a causal relationship between suicide rates and economic or climate variables. These should be considered together with increasing concerns on the possible effect of climate change on mental health
Ambient temperature and solar insolation are associated with decreased prevalence of SSRI-treated psychiatric disorders
2019, Journal of Psychiatric Research
Serotonergic function is known to fluctuate in association with light and temperature. Serotonin-related behaviors and disorders similarly vary with climatic exposure, but the associations are complex. This complexity may reflect the importance of dose and timing of exposure, as well as acclimation. This cross-sectional study tests how average climate exposures (ambient temperature and solar insolation) vary with the prevalence of a group of SSRI-treated disorders. For comparison, we similarly studied a group of disorders not treated by SSRIs (i.e substance use disorders). Psychiatric prevalence data were obtained from the Collaborative Psychiatric Epidemiology Surveys (CPES). Average yearly solar insolation was obtained from NASA's NLDAS-2 Forcing Dataset Information. Average yearly temperature was obtained from NOAA's US Climate Normals. Logistic regression models were generated to assess the relationship between these two climatic factors and the prevalence of SSRI-treated and substance use disorders. Age, gender, race, income, and education were included in the models to control for possible confounding. Temperature and insolation were significantly associated with the SSRI-responsive group. For an average 1 GJ/m²/year increase, OR was 0.90 (95% CI 0.85–0.96, p = 0.001), and for an average 10 °F increase, OR was 0.93 (95% CI 0.88–0.97, p = 0.001). This relationship was not seen with substance use disorders (insolation OR: 0.97, p = 0.682; temperature OR: 0.96, p = 0.481). These results warrant further investigation, but they support the hypothesis that chronic exposure to increased temperature and light positively impact serotonin function, and are associated with reduced prevalence of some psychiatric disorders. They also support further investigation of light and hyperthermia treatments.
Ambient temperature, sunlight duration, and suicide: A systematic review and meta-analysis
2019, Science of the Total Environment
Citation Excerpt :
Another explanation is that elevated temperature can increase impulsive and aggressive behavior through high serotonin levels (serotonin or 5-HT receptors) (Doleski et al., 2010; Lambert et al., 2002; Maes et al., 1995; Molteni et al., 2010; Olivier et al., 2010; Stefulj et al., 2004). Additionally, peaks of suicide rate in cold weather also documented in some regions (Souetre et al., 1990; Tietjen and Kripke, 1994; Linkowski et al., 1992; Thorson and Kasworm, 2007; Tsai, 2010). A possible reason may be that the reduced frequency of social intercourse in winter months could have a negative effect on how a depressed individual copes with stress, and then increase the risk of suicide (Lester, 1995).
The relationship between sunlight hours, temperature, and suicide has been investigated in many previous studies, but with inconsistent findings. We conducted this meta-analysis aiming at providing clear evidence about whether sunlight hours and temperature can affect the risk of suicide.
Relevant literature published before 7 Jul 2018 was searched in three electronic database of PubMed, Web of science and Cochrane. Between-study heterogeneity in the effect estimates were examined by study design (i.e., exposure time resolution, temperature measure and suicide classification) and population vulnerability (i.e., sex, national income level, climate zone and study location).
Regarding temperature-suicide association, we identified 14 studies that provided 23 effect estimates for meta-analysis. Our random-effects model showed that each 1 °C increase in temperature was significantly associated with a 1% increase in the incidence of suicide (Incidence Rate Radio (IRR) = 1.01; 95%CI = 1.00–1.02; p < 0.05). As for sunlight duration and suicide, 11 effect estimates from 4 studies were pooled using a fixed-effects model. Significant association between sunlight duration (per 1 h increase) and the risk of suicide was not observed, and the pooled IRR was 1.00 (95%CI = 0.99–1.01; p > 0.05). There was significant heterogeneity between previous studies' effect estimates, and significantly lower heterogeneity was noted for the female group, for studies that did analyses at daily scale, and for studies using mean temperature as the exposure indicator.
Our findings suggest a significant and positive association between temperature rises and incidence of suicide, and a non-significant association between sunlight duration and incidence of suicide. Populations living in tropical and temperate zones or at middle-income level may be particularly vulnerable to temperature increase.
Season, weather, and suicide–Further evidence for ecological complexity
2018, Neurology Psychiatry and Brain Research
easonality in suicide is reported worldwide, and peaks in late spring. Despite the potential connection to the weather, associations between meteorological variables and suicide does not explain seasonality. Studies testing for seasonality while controlling for the weather show patterns that are more complex than a straightforward link between spring-like weather and suicide.
We tested whether seasonality in suicide was due to meteorological variation (hours of sunshine, rainfall, or temperature) in a novel population (Scotland; 2003–2013). We also sought to further explore the ecological complexity demonstrated in previous work by testing associations at a single location (Tay Road Bridge; 1968–2017). RESULTS: We found peaks in suicidal behavior in June at the bridge, but no seasonality for Scotland as a whole. Seasonality was reduced when we controlled for maximum temperature and hours of sunshine. We found patterns to be dependent upon sex, with stronger seasonal and meteorological effects amongst men.
Our study was exploratory and relies on population-level data.
Seasonal and meteorological effects on suicide are dependent upon local and individual context, with significant effects apparent at the Tay Road Bridge and not across Scotland as a whole. Men may be more sensitive to season and weather. In order to determine whether seasonality in suicide is due to meteorological variation, future research should test patterns in small geographical units, in men and women, and for different suicide methods, and seek to identify the social and physical factors which predict variation in patterns.
Identifying critical green structure characteristics for reducing the suicide rate
2018, Urban Forestry and Urban Greening
Green space has both environmental and health benefits, especially in moderating temperature and improving mental health. However, the characteristics of green structures have been overlooked in previous studies, and the mediation effects of green structures on the suicide rate have not been analyzed. To evaluate the mediation impacts of green structures (patch area, fragmentation, and patch distance), this study explored the potential pathways and effects of green structures on the suicide rate using partial least squares modeling with data from Taiwan. Other factors influencing the suicide rate, such as economic status, an aging population, population density, and temperature were also considered in the model. The results revealed a negative association between the suicide rate and patch area (standardized total effect coefficient (STEC) = −0.42), but there were positive associations with fragmentation (STEC = 0.14), and patch distance (STEC = 0.35) of green structures. Therefore, maximizing the patch area, and minimizing fragmentation and patch distance can contribute to a reduction in the suicide rate. Fragmentation minimization was found to be crucial for both genders, while patch-area maximization and patch-distance minimization were only influential for females. Moreover, economic status, an aging population, population density, and temperature were influential for both genders. This is the first study to consider the direct and indirect pathways and effects of the green structure on suicide rate. Instead of considering only the area covered by green spaces, it was found that other characteristics of green structures should also be considered when formulating greening policies.

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Influence of environmental factors on suicidal behavior

Abstract

British Journal of Psychiatry

Journal of Affective Disorders

Relationship between unemployment rates and suicide rates in eight countries

Psychological Reports

Mortality and economic instability

International Journal of Health Services

The ecological pattern of suicide and parasuicide in Edinburgh

Social Science and Medicine

A Register of Social and Medical Indices by Local Government Area in Edinburgh and the Lothians

Weather and suicide

Transactions of the American Clinical and Climatological Association

Suicide and climatology

Archives of Environmental Health

Suicide

Le Suicide

Seasonal patterns of suicide, depression and electroconvulsive therapy

British Journal of Psychiatry

Suicide rates among public mental health patients

Acta Psychiatrica Scandinavica

Suicide mortality in Greater London: Changes during the past 25 years

British Journal of Preventive and Social Medicine

Completed suicide and latitude

Psychological Reports

Completed suicide and longitude

Psychological Reports