Effect of some climatic factors on violent and non-violent suicides in Belgium

doi:10.1016/0165-0327(92)90001-M

Journal of Affective Disorders

Volume 25, Issue 3, July 1992, Pages 161-166

https://doi.org/10.1016/0165-0327(92)90001-M Get rights and content

Abstract

We explored the differential effect of some climatic factors such as temperature, atmospheric pressure, sunlight duration and humidity grade on the temporal distribution of violent and non-violent suicides, accidental and undetermined causes of death as well as homicides in Belgium, between 1969 and 1984.

Our study indicates that temperature and sunlight duration are specifically associated with the probability of violent suicide, while deaths due to non-violent causes (such as non-violent suicides) did not show any relationship to climatic factors.

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2022, Economics and Human Biology
Citation Excerpt :
Some argue that men are more impulsive than women are, which explains significant results from daylight on male suicides but less so for female suicides (Preti and Miotto, 1998). Several researchers argue that impulsive actions, relating to daylight and serotonin levels, explain why there is a significant correlation between daylight and violent suicides, and a non-significant relationship with non-violent suicides (Linkowski et al., 1992; Maes et al., 1994; Preti and Miotto, 1998; Lin et al., 2008; Reutfors et al., 2009; Vyssoki et al., 2012). Impulsivity may also change throughout one’s life course.
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 %).
The role of seasonality and photoperiod on the lethality of suicide attempts: A case-control study
2019, Journal of Affective Disorders
The risk factors related to suicidal behaviors are complex and not yet fully known. Several studies underline how suicide results from the combination of psycho-social, biological, cultural, and environmental factors. The aim of this study was to investigate the potential role of seasonality and photoperiod on high-lethality suicide attempts (HLSA) compared with low-lethality suicide attempts (LLSA) in a sample of psychiatric inpatients.
After attempting suicide, subjects were admitted in the emergency/psychiatric ward of the IRCCS Ospedale Policlinico San Martino from 1st August 2013 to 31st July 2018. Socio-demographic and clinical characteristics were collected.
The sample consisted of four hundred thirty-two individuals admitted for suicide attempt. One hundred thirty-three subjects (30.8%) of the sample committed a HLSA. The HLSA group peaked in the months with a higher sunlight exposure (June and July). Bivariate correlation analyses between seasonality/photoperiod in the whole sample and HLSA were positively associated with summer and highest solar intensity period.
Data were limited to a single hospital, patients’ seasonal environment, meteorological variables and psychological factors. In addition, the presence of acute life-events fostering the suicidal crisis has not been investigated.
The current study provides a novel perspective on the questions surrounding the impact of seasonality and daylight exposure on lethality of suicide attempts. further studies are needed to provide deeper understandings on the delicate molecular network that links suicide behaviors, seasonality and daylight in order to develop more effective prevention and treatment strategies in the future.
Ambient temperature and solar insolation are associated with decreased prevalence of SSRI-treated psychiatric disorders
2019, Journal of Psychiatric Research
Citation Excerpt :
Serotonin abnormalities are also strongly linked with impulsive violence (Virkkunen et al., 1996), and multiple studies show that hotter climates and hotter days in a given location are correlated with higher rates of violence (Gamble and Hess, 2012; Sorg and Taylor, 2011). Similarly, several studies have identified violent suicide to be specifically correlated with acute increases in temperature and sunlight (Dixon et al., 2014; Hee-Jung et al., 2017; Linkowski et al., 1992). There are multiple reasons to think that patients with presumed serotonergic disturbances might struggle with acute changes in climate.
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
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
Citation Excerpt :
Temperature and precipitation are, of course, closely correlated with hours of sunshine, and the independent consequences of each are difficult to disentangle (Bazas et al., 1979; Lambert et al., 2002). As with hours of sunshine, suicide rates have been shown to increase with both colder (Linkowski et al., 1992; Souetre et al., 1987; Souêtre et al., 1990; Tsai, 2010) and hotter (Dixon et al., 2014; Dixon and Kalkstein, 2018; Kim et al., 2011; Lee et al., 2006; Likhvar et al., 2011; Page et al., 2007) temperatures, and to be uncorrelated (Dixon et al., 2007). Higher rainfall has been shown to be associated with increased numbers of suicide attempts (Barker et al., 1994), but not with suicide rates (Ajdacic-Gross et al., 2007).
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.
Associations between high ambient temperatures and heat waves with mental health outcomes: a systematic review
2018, Public Health
The objective of this study was to describe the mental health effects of high ambient temperatures and heat waves, determine whether heat-related morbidity and mortality are increased among people with known mental disorders and identify knowledge gaps to inform targeting of future research.
Systematic literature review and narrative synthesis.
A systematic review of published literature using MEDLINE, Embase and PsycINFO without geographical or temporal limits was conducted. We included studies that explicitly linked high ambient temperatures and/or heat waves to mental health outcomes. Evidence was graded using a National Institute of Health framework.
A total of 35 studies were included in the review, among which 34 were observational studies and one was a case–control study. Six broad mental health outcome categories were identified: suicide and heat; bipolar disorder, mania and depression and heat; schizophrenia and heat; organic mental health outcomes and heat including dementia; alcohol and substance misuse and heat; and multiple mental health outcomes/mental health service usage and heat. The studies included were heterogeneous in terms of study design, population, setting, exposure measures, outcomes and location making meta-analysis unfeasible. Fifteen studies showed an increased suicide risk with heat (relative risk [RR] 1.014–1.37 per 1 °C, P < 0.05; r = 0.10–0.64, P < 0.05). Increased risks of mental health-related admissions and emergency department visits at higher temperatures were also found. No evidence of change in community care use was found. Evidence for the impact of heat on other mental health outcomes was mixed.
High ambient temperatures have a range of mental health effects. The strongest evidence was found for increased suicide risk. Limited evidence was found for an increase in heat-related morbidity and mortality among people with known mental health problems. Knowledge gaps exist on the impact of high temperatures on many common mental health disorders. Mental health impacts should be incorporated into plans for the public health response to high temperatures, and as evidence evolves, psychological morbidity and mortality temperature thresholds should be incorporated into hot weather–warning systems.

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Effect of some climatic factors on violent and non-violent suicides in Belgium

Abstract

Psychiatr. Res.

J. Affect. Disord.

Psychiatr. Res.

Annual rhythms in man

Monoamine metabolites in cerebro-spinal fluid in relation to depressive illness, suicidal behavior and personality

Biological factors in suicide

Seasonal variation in some mental health statistics suicides, homicides, psychiatric admissions and institutional placement of the retarded

J. Clin. Psychol.