Seasonality of suicide: a multi-country multi-community observational study

Do moral values change with the seasons?

Moral values guide consequential attitudes and actions. Here, we report evidence of seasonal variation in Americans' endorsement of some-but not all-moral values. Studies 1 and 2 examined a decade of data from the United States (total N = 232,975) and produced consistent evidence of a biannual seasonal cycle in values pertaining to loyalty, authority, and purity ("binding" moral values)-with strongest endorsement in spring and autumn and weakest endorsement in summer and winter-but not in values pertaining to care and fairness ("individualizing" moral values). Study 2 also provided some evidence that the summer decrease, but not the winter decrease, in binding moral value endorsement was stronger in regions with greater seasonal extremity. Analyses on an additional year of US data (study 3; n = 24,199) provided further replication and showed that this biannual seasonal cycle cannot be easily dismissed as a sampling artifact. Study 4 provided a partial explanation for the biannual seasonal cycle in Americans' endorsement of binding moral values by showing that it was predicted by an analogous seasonal cycle in Americans' experience of anxiety. Study 5 tested the generalizability of the primary findings and found similar seasonal cycles in endorsement of binding moral values in Canada and Australia (but not in the United Kingdom). Collectively, results from these five studies provide evidence that moral values change with the seasons, with intriguing implications for additional outcomes that can be affected by those values (e.g., intergroup prejudices, political attitudes, legal judgments).

Suicide, neuroinflammation and other physiological alterations

Suicide is considered one of the major public health problems worldwide, being the second leading cause of death in the 15-29 age group. It is estimated that every 40s someone in the world commits suicide. The social taboo surrounding this phenomenon as well as the fact that suicide prevention measures currently fail to avoid deaths from this cause, means that more research is needed to understand its mechanisms. The present narrative review on suicide tries to point out several important aspects, such as risk factors or the dynamics of suicide, as well as the current findings in the field of physiology that could offer advances in the understanding of suicide. Subjective measures of risk such as scales and questionnaires are not effective alone, whereas the objective measures can be addressed from physiology. Thus, an increased neuroinflammation in people who take their own lives has been found, with an increase in inflammatory markers such as interleukin-6 and other cytokines in plasma or cerebrospinal fluid. Also, the hyperactivity of the hypothalamic-pituitary-adrenal axis and a decrease in serotonin or in vitamin D levels seems to also be involved. In conclusion, this review could help to understand which factors can trigger an increased risk of dying by suicide, as well as pointing out those alterations that occur in the body when someone attempt to commit suicide or succeeds in taking their own life. There is a need for more multidisciplinary approaches that address suicide to help to raise awareness of the relevance of this problem that causes the death of thousands of people every year.

Association Between Prosuicide Website Searches Through Google and Suicide Death in the United States From 2010 to 2021: Lagged Time-Series Analysis

BACKGROUND

 The rate of suicide death has been increasing, making understanding risk factors of growing importance. While exposure to explicit suicide-related media, such as description of means in news reports or sensationalized fictional portrayal, is known to increase population suicide rates, it is not known whether prosuicide website forums, which often promote or facilitate information about fatal suicide means, are related to change in suicide deaths overall or by specific means.

OBJECTIVE

 This study aimed to estimate the association of the frequency of Google searches of known prosuicide web forums and content with death by suicide over time in the United States, by age, sex, and means of death.

METHODS

 National monthly Google search data for names of common prosuicide websites between January 2010 and December 2021 were extracted from Google Health Trends API (application programming interface). Suicide deaths were identified using the CDC (Centers for Disease Control and Prevention) National Vital Statistics System (NVSS), and 3 primary means of death were identified (poisoning, suffocation, and firearm). Distributed lag nonlinear models (DLNMs) were then used to estimate the lagged association between the number of Google searches on suicide mortality, stratified by age, sex, and means, and adjusted for month. Sensitivity analyses, including using autoregressive integrated moving average (ARIMA) modeling approaches, were also conducted.

RESULTS

 Months in the United States in which search rates for prosuicide websites increased had more documented deaths by intentional poisoning and suffocation among both adolescents and adults. For example, the risk of poisoning suicide among youth and young adults (age 10-24 years) was 1.79 (95% CI 1.06-3.03) times higher in months with 22 searches per 10 million as compared to 0 searches. The risk of poisoning suicide among adults aged 25-64 was 1.10 (95% CI 1.03-1.16) times higher 1 month after searches reached 9 per 10 million compared with 0 searches. We also observed that increased search rates were associated with fewer youth suicide deaths by firearms with a 3-month time lag for adolescents. These models were robust to sensitivity tests.

CONCLUSIONS

 Although more analysis is needed, the findings are suggestive of an association between increased prosuicide website access and increased suicide deaths, specifically deaths by poisoning and suffocation. These findings emphasize the need to further investigate sites containing potentially dangerous information and their associations with deaths by suicide, as they may affect vulnerable individuals.

Evaluating Population-Level Interventions and Exposures for Suicide Prevention

Evaluations of interventions targeting the population level are an essential component of the policy development cycle. Pre-post designs are widespread in suicide prevention research but have several significant limitations. To inform future evaluations, our aim is to explore the three most frequently used approaches for assessing the association between population-level interventions or exposures and suicide - the pre-post design, the difference-in-difference design, and Poisson regression approaches. The pre-post design and the difference-in-difference design will only produce unbiased estimates of an association if there are no underlying time trends in the data and there is no additional confounding from other sources. Poisson regression approaches with covariates for time can control for underlying time trends as well as the effects of other confounding factors. Our recommendation is that the default position should be to model the effects of population-level interventions or exposures using regression methods that account for time effects. The other designs should be seen as fall-back positions when insufficient data are available to use methods that control for time effects.

Comparing frequencies of adolescent suicide attempters pre- and during COVID-19 pandemic school terms

BACKGROUND

The COVID-19 pandemic had and still have a major impact on adolescent mental health and consequently on suicidal behavior. However, few studies have investigated whether the pandemic has changed the patterns and the triggers of suicidality peaks in adolescents, e.g., seasonal patterns or family conflicts. We hypothesized that the pandemic modified suicidality rates: an increment of suicide attempts would be observed in the first semester of the academic year during COVID-19 pandemic compared to the same period of previous academic year; and the precipitating factors would be more related to social stressors during the pandemic school year.

METHODS

A retrospective cross-sectional study was conducted to assess the precipitating factors, also including school-related factors and cognitive skills, of adolescent suicide attempters occurred in the first and second semesters of the year before the pandemic lockdown (study periods 1 and 2) and the year after (study periods 3 and 4).

RESULTS

The sample consisted of 85 adolescents aged between 12 and 17 recruited consecutively from March 2019 to March 2021 at emergency ward because of suicide attempt. Forty-eight adolescents (55.3% of the sample) were attended before the lockdown (pre-pandemic group) and 38 (44.7%) the year after. The results showed a higher proportion of female suicide attempters in period 4 (Sept 2020-Feb 2021) respect to period 3 (Mar 2020-Aug 2020), i.e., pandemic semesters compared with the increment observed between period 2 and 1 (prepandemic semesters; Fisher's exact test = 4.73; p = 0.026). The multinomial regression models showed a significant effect in the frequency of adolescents who attempted suicide (ratio χ2 = 15.19, p = 0.019), accounted by the differences between period 4 (Sept 2020-Feb 2021) and period 1 (Mar 2019-Aug 2019), with depressive symptoms being a significant contributing factor (Exp(b) = 0.93; p = 0.04). Additionally, social triggers and age were found to be significant risk factors for suicide attempts in the first semester of the pandemic academic year (period 4) compared to the same semester of the pre-pandemic year (period 2; Exp(b) = 0.16, p = 0.01, and Exp(b) = 1.88, p = 0.006, respectively).

CONCLUSIONS

During the pandemic, the decrement between first and second semester of the number of females attempting suicide was more pronounced than in the prepandemic school year -though this findings lacked statistical power due to very limited sample size-. Change in the frequency of adolescent attempting suicide in the different school periods was associated with greater severity of depressive symptoms. Social relations in back-to-school after the lockdown were also associated with the number of adolescents attempting suicide.

Higher Seasonal Variation of Systemic Inflammation in Bipolar Disorder

Seasonal rhythms affect the immune system. Evidence supports the involvement of immuno-inflammatory mechanisms in bipolar disorder (BD), with the neutrophil to lymphocyte ratio (NLR), and the systemic immune-inflammatory index (SII; platelets × neutrophils/lymphocytes) consistently reported to be higher in patients with BD than in HC, but seasonal rhythms of innate and adaptive immunity have never been studied. We retrospectively studied NLR and SII in 824 participants divided into three groups: 321 consecutively admitted inpatients affected by a major depressive episode in course of BD, and 255 consecutively admitted inpatients affected by obsessive-compulsive disorder (OCD; positive psychiatric control), and 248 healthy controls (HC). Patients with BD showed markedly higher markers of systemic inflammation in autumn and winter, but not in spring and summer, in respect to both HC and patients with OCD, thus suggesting a specific effect of season on inflammatory markers in BD, independent of a shared hospital setting and drug treatment. Given that systemic inflammation is emerging as a new marker and as target for treatment in depressive disorders, we suggest that seasonal rhythms should be considered for tailoring antidepressant immuno-modulatory treatments in a precision medicine approach.

A Descriptive Study of the Characteristics of Homicide-Suicide in Forensic Autopsy Cases

Homicide followed by suicide (HS) is a tragic event with varied characteristics across countries and regions. Compared to Western countries, there are limited studies on HS in Asian countries. Therefore, this study aimed to clarify the characteristics of recent HS cases by examining forensic autopsy records from 2008 to 2020 collected from the Department of Legal Medicine, Chiba University, in Japan. A total of 77 HS cases were identified, involving 77 perpetrators (52 completed suicides, 25 attempted suicides), with 28 perpetrator and 89 victim autopsies. Our findings showed that older adults accounted for nearly half of the victims; victims were mostly females, whereas most perpetrators were male. The most common HS relationship was that between a parent and a child. Autopsy findings showed that the most common cause of death was strangulation, and illegal drugs were detected only in a few cases; however, psychotropic drugs were detected in child victims. No obvious evidence of past child physical abuse by caregivers was found. In contrast, intimate partner violence (IPV) was present, with a history of IPV found in half of HS cases involving adult intimate partner relationships. Notably, gender differences in age and relationship to the victim were identified. Likewise, some perpetrators may have expressed their plans and intentions for HS before the event, which may represent an important sign for HS prevention. However, to accurately reveal the course of HS, nationwide integrated statistics, forensic autopsies, including toxicological analyses of the deceased; and forensic psychiatric perspectives, including psychological autopsy, are required.

Evening Chronotype and Suicide: Exploring Neuroinflammation and Psychopathological Dimensions as Possible Bridging Factors-A Narrative Review

A chronotype is generally defined as the variability of the phase angle of entrainment, while the latter reflects the relationship between the timing of a certain rhythm (e.g., the sleep-wake cycle) and the timing of an external temporal cue. Individuals can be placed on a spectrum from "morning types" (M types) to "evening types" (E types). E-chronotype has been proposed as a transdiagnostic risk factor for psychiatric conditions, and it has been associated with psychopathological dimensions. Eveningness seems to be correlated with both suicidal ideation (SI) and suicidal behavior (SB) through several possible mediating factors. Immunological alterations have also been linked to later chronotypes and SI/SB. This narrative review aims to summarize the evidence supporting the possible association between chronotypes and suicide and the eventual mediating role of neuroinflammation and several psychopathological dimensions. A search of the literature (2003-2023) was conducted using various databases: PUBMED, EMBASE, Scopus, UpToDate, PsycINFO, and Cochrane Library. English-language articles were collected and screened for eligibility. Despite the apparent absence of a direct correlation between E-chronotype and suicidality, E-chronotype promotes a chain of effects that could be involved in an increased risk of SB, in which with neuroinflammation possibly plays an intriguing role and some psychopathological dimensions may stand out.

Seasonal patterns of sickness absence due to diagnosed mental disorders: a nationwide 12-year register linkage study

AIMS

Although seasonality has been documented for mental disorders, it is unknown whether similar patterns can be observed in employee sickness absence from work due to a wide range of mental disorders with different severity level, and to what extent the rate of change in light exposure plays a role. To address these limitations, we used daily based sickness absence records to examine seasonal patterns in employee sickness absence due to mental disorders.

METHODS

We used nationwide diagnosis-specific psychiatric sickness absence claims data from 2006 to 2017 for adult individuals aged 16-67 (n = 636,543 sickness absence episodes) in Finland, a high-latitude country with a profound variation in daylength. The smoothed time-series of the ratio of observed and expected (O/E) daily counts of episodes were estimated, adjusted for variation in all-cause sickness absence rates during the year.

RESULTS

Unipolar depressive disorders peaked in October-November and dipped in July, with similar associations in all forms of depression. Also, anxiety and non-organic sleep disorders peaked in October-November. Anxiety disorders dipped in January-February and in July-August, while non-organic sleep disorders dipped in April-August. Manic episodes reached a peak from March to July and dipped in September-November and in January-February. Seasonality was not dependent on the severity of the depressive disorder.

CONCLUSIONS

These results suggest a seasonal variation in sickness absence due to common mental disorders and bipolar disorder, with high peaks in depressive, anxiety and sleep disorders towards the end of the year and a peak in manic episodes starting in spring. Rapid changes in light exposure may contribute to sickness absence due to bipolar disorder. The findings can help clinicians and workplaces prepare for seasonal variations in healthcare needs.

Longitude-based time zone partitions and rates of suicide

BACKGROUND

Increasing evidence suggests that conditions with decreased morning and increased evening light exposure, including shift work, daylight-saving time, and eveningness, are associated with elevated mortality and suicide risk. Given that the alignment between the astronomical, biological, and social time varies across a time zone, with later-shifted daylight exposure in the western partition, we hypothesized that western time zone partitions would have higher suicide rates than eastern partitions.

METHODS

United States (U.S.) county-level suicide and demographic data, from 2010 to 2018, were obtained from a Centers for Disease Control database. Using longitude and latitude, counties were sorted into the western, middle, or eastern partition of their respective time zones, as well as the northern and southern halves of the U.S. Linear regressions were used to estimate the associations between suicide rates and time zone partitions, adjusting for gender, race, ethnicity, age group, and unemployment rates.

RESULTS

Data were available for 2872 counties. Across the U.S., western partitions had statistically significantly higher rates of suicide compared to eastern partitions and averaged up to two additional yearly deaths per 100,000 people (p < .001).

LIMITATIONS

Ecological design and limited adjustment for socioeconomic factors.

CONCLUSIONS

To our knowledge, this is the first study of the relationship between longitude-based time zone partitions and suicide. The results were consistent with the hypothesized elevated suicide rates in the western partitions, and concordant with previous reports on cancer mortality and transportation fatalities. The next step is to retest the hypothesis with individual-level data, accounting for latitude, photoperiodic changes, daylight-saving time, geoclimatic variables, physical and mental health indicators, as well as socioeconomic adversity and protection.

Impact of pesticide regulations on mortality from suicide by pesticide in China: an interrupted time series analysis

Background

Pesticide bans and regulatory restrictions have been shown to be effective strategies for preventing suicide in several countries. Suicide and suicide by pesticides have decreased significantly in China over the past two decades. However, whether the reduction was associated with pesticide regulation is unknown.

Methods

The monthly data on suicide and suicide by pesticide from 2006 to 2018 were obtained from China's Disease Surveillance Point (DSP) system. Information on China's pesticide regulations since 1970 was obtained from Pesticide Action Network International (PAN International), Joint Meeting on Pesticide Management Highly Hazardous Pesticides (JMPM HHP) lists, the website of the Ministry of Agriculture of China, Pesticide Information Network of China, and the Wan Fang database. Change point detection and policy analysis were combined to identify the time of any trend change breakpoint of suicide and suicide by pesticide. Interrupted time series analysis was used to investigate the pre- and post-breakpoint trends of monthly standardized rates in suicide and suicide by pesticide.

Results

The standardized pesticide suicide rate decreased by 60.5% from 6.50 in 2006 to 2.56 per 100,000 in 2018. Larger declines were evident among people in urban areas (67.3%), female individuals (63.5%), and people aged 15-44 years (68.1%). The effect of policies banning highly hazardous organophosphorus pesticides (HHOP) [rate ratio (RR) = 0.993, 95% CIs (0.991-0.994)] in December 2008 and stopping domestic sales and use of paraquat aqueous solution (RR = 0.992, 95% CIs: 0.990-0.994) in July 2016 were more pronounced than regulating the paraquat-related products (RR = 1.003, 95% CIs: 1.002-1.004) in April 2012.

Conclusion

Declines in suicide by pesticide in China occurred contemporaneously with regulatory bans and restrictions implemented on several pesticides, particularly in urban areas, among female individuals, and the relatively low age profile. These findings indicate the potential influence of these bans on trends of suicide by pesticides.

Monday peak is unique to suicide? Comparison of weekly distribution by causes of death using national representative cohort database

INTRODUCTION

The excess suicide mortality on Monday was reported in numerous studies. However, it is uncertain that the uneven weekly distribution of deaths is observed among suicide, or common among various causes of death.

METHODS

Weekly distributions of suicide and other causes of death from 2012 to 2017 in South Korea were compared. Logistic regression models were fitted to investigate the association between causes of death and day-of-the-week effects. We also fitted conditional logistic regression models after age and gender matching.

RESULTS

A total of 1,622,213 deaths, including 80,492 suicide decedents, were analyzed. A total of 16.0% of suicide deaths occurred on Monday, whereas 12.4% on Saturday and 13.0% on Sunday. Suicide decedents were more likely to die on Monday than other causes of deaths after controlling sociodemographic factors in unmatched data. However, there was no evidence of excess suicide deaths on Mondays than other days in contrast to matched death controls.

CONCLUSION

While the increase in mortality on Mondays was not unique to suicide, our findings have suicide prevention implications. Mental health practitioners should consider providing additional mental health resources on earlier working days. Workplace mental health programs to reduce psychological burdens of employees could help to prevent suicide during working days.

Trends and Seasonality of Emergency Department Visits and Hospitalizations for Suicidality Among Children and Adolescents in the US from 2016 to 2021

Importance

The detection of seasonal patterns in suicidality should be of interest to clinicians and US public health officials, as intervention efforts can benefit by targeting periods of heightened risk.

Objectives

To examine recent trends in suicidality rates, quantify the seasonality in suicidality, and demonstrate the disrupted seasonality patterns during the spring 2020 COVID-19-related school closures among US children and adolescents.

Design, Setting, and Participants

This population-based, descriptive cross-sectional study used administrative claims data from Optum's deidentifed Clinformatics Data Mart Database. Participants included children aged 10 to 12 years and adolescents aged 13 to 18 years who were commercially insured from January 1, 2016, to December 31, 2021. Statistical analysis was conducted between April and November 2022.

Exposures

Month of the year and COVID-19 pandemic.

Main Outcomes and Measures

Rates and seasonal patterns of emergency department (ED) visits and hospitalizations for suicidality.

Results

The analysis included 73 123 ED visits and hospitalizations for suicidality reported between 2016 and 2021. Among these events, 66.1% were reported for females, and the mean (SD) age at the time of the event was 15.4 (2.0) years. The mean annual incidence of ED visits and hospitalizations for suicidality was 964 per 100 000 children and adolescents (95% CI, 956-972 per 100 000), which increased from 760 per 100 000 (95% CI, 745-775 per 100 000) in 2016 to 1006 per 100 000 (95% CI, 988-10 024 per 100 000) in 2019, with a temporary decrease to 942 per 100 000 (95% CI, 924-960 per 100 000) in 2020 and a subsequent increase to 1160 per 100 000 (95% CI, 1140-1181 per 100 000) in 2021. Compared with January, seasonal patterns showed peaks in April (incidence rate ratio [IRR], 1.15 [95% CI, 1.11-1.19]) and October (IRR, 1.24 [95% CI, 1.19-1.29]) and a nadir in July (IRR, 0.63 [95% CI, 0.61-0.66]) during pre-COVID-19 years and 2021. However, during the spring of 2020, which coincided with school closures, seasonal patterns were disrupted and April and May exhibited the lowest rates.

Conclusions and Relevance

The findings of this study indicated the presence of seasonal patterns and an observed unexpected decrease in suicidality among children and adolescents after COVID-19-related school closures in March 2020, which suggest a potential association between suicidality and the school calendar.

Suicidality and mood: the impact of trends, seasons, day of the week, and time of day on explicit and implicit cognitions among an online community sample

Decades of research have established seasonality effects on completed and attempted suicides, with rates increasing in spring. Little advancements have been made to explain this phenomenon, with most studies focusing almost exclusively on the number of suicide attempts and deaths. Using more than six years of data collected among a US, UK, and Canadian online community sample (N > 10,000), we used newly developed Prophet forecasting and autoregressive-integrated moving average time-series models to examine the temporal dynamics of explicit and implicit self-harm cognitions. We created three groups (past suicide attempters; suicide ideation and/or non-suicidal self-injury; no previous self-harm, suicidal thoughts, or behaviors). We found a general increase of negative self-harm cognitions across the six years and seasonality effects for mood and desire to die, particularly among those who previously made a suicide attempt. Negative explicit self-harm cognitions peaked in winter (December), with implicit self-harm showing a lagged peak of two months (February). Moreover, daily negative self-harm cognitions consistently peaked around 4-5 am, with implicit cognitions again showing a lagged effect (1-hour). Limitations include the volunteer sample not being representative and the cross-sectional nature of the data being unable to separate between-subject and within-subject structural trends in the time series. Our findings show that negative explicit and implicit cognitions precede the rise in suicidal behaviors in spring. We proposed a conceptual model of seasonal suicide risk that may offer fertile ground for theoretical advancements, including implications for clinical risk assessment and public policies regarding the availability of health services.

Daily changes in ambient air pollution concentrations and temperature and suicide mortality in Canada: Findings from a national time-stratified case-crossover study

INTRODUCTION

Worldwide, approximately 1900 people die by suicide daily. Daily elevations in air pollution and temperature have previously been linked to a higher risk of death from suicide. To date, there have been relatively few studies of air pollution and suicide, particularly at a national level. National analyses play an important role in shaping health policy to mitigate against adverse health outcomes.

METHODS

We used a time-stratified case-crossover study design to investigate the influence of short-term (i.e., day to day) interquartile range (IQR) increases in air pollutants (nitrogen dioxide [NO₂], ozone [O₃], and fine particulate matter [PM_2.5]) and temperature on suicide mortality in Canada between 2002 and 2015. For air pollution models, odds ratios (ORs) derived from conditional logistic regression models were adjusted for average daily temperature, and holidays. For temperature models, ORs were adjusted for holidays. Stratified analyses were undertaken by suicide type (non-violent and violent), sex, age, and season.

RESULTS

Analyses are based on 50,800 suicide deaths. Overall, temperature effects were stronger than those for air pollution. A same day IQR increase in temperature (9.6 °C) was associated with a 10.1% increase (95% confidence interval (CI): 9.0%-11.2%) of death from suicide. For 3-day average increase of O₃ (IQR = 14.1 ppb), PM_2.5 (IQR = 5.6 μg/m³) and NO₂ (IQR = 9.7 ppb) the corresponding risks were 4.7% (95% CI: 3.9, 5.6), 3.4% (95% CI: 3.0, 3.8), and 2.0% (95% CI: 1.1, 2.8), respectively. All pollutants showed stronger associations with suicide during the warmer season (April-September). Stratified analyses revealed stronger associations for both temperature and air pollution in women.

CONCLUSIONS

Daily increases in air pollution and temperature were found to increase the risk of death from suicide. Females, particularly during warmer season, were most vulnerable to these exposures. Policy decisions related to air pollution and climate change should consider effects on mental health.

Seasonality and the female happiness paradox

Most studies tracking wellbeing do not collect data across all the months in a year. This leads to error in estimating gender differences in wellbeing for three reasons. First, there are seasonal patterns in wellbeing (particularly life satisfaction and happiness) which are gendered, so failure to account for those confounds estimates of gender differences over time. Second, studies fielded in discrete parts of the year cannot extrapolate to gender differences in other parts of the year. Making inferences about trends over time is particularly problematic when a survey changes its field survey dates across years. Third, without monthly data, surveys miss big shifts in wellbeing that occur for short periods. This is a problem because women's wellbeing is more variable over short periods of time than men's wellbeing. It also bounces back faster. We show that simply splitting the data by months in a happiness equation generates a positive male coefficient in one subset of months from September to January and a negative coefficient in months February to August. Such a split has no impact on the male coefficients in an anxiety equation. Months matter.

Seasonal and Temporal Patterns of Homicides and Suicides in Cali and Manizales, Colombia: A Times-Series Analysis 2008-2015

OBJECTIVE

To identify seasonal and temporal variations in daily incidence of homicides and suicides in Cali and Manizales, Colombia during 2008-2015.

MATERIALS AND METHODS

An ecological time series study was performed using negative binomial regression models for daily incidence of homicides and suicides; analyses were controlled for yearly trends and temporal autocorrelations.

RESULTS

Saturdays, Sundays, December holidays as well as New Year and New Year's Eve were associated with an increased risk of homicides in both cities. Suicide risk increased during December holidays and New Year in both cities. In addition, the suicide risk increased on paydays, Saturdays, Sundays, and Mondays in Cali, and it decreased during the Holy Week holidays in Manizales. December patterns of suicides and homicides are the opposite in each city, and between cities.

CONCLUSIONS

The incidences of homicides and suicides are not homogeneous over time. These patterns can be explained partially by alcohol consumption and changes in people's routine activities which may modify exposure to violent circumstances.

[Forensic medical characteristic of hanging incidents among juvenile]

THE AIM OF THE STUDY

Was to conduct the epidemiological analysis of juveniles' deaths by hanging, registered in the Bureau of Forensic Medical Expertise, Moscow for 2017-2021 years. The number of incidents equal 61 was revealed (2.65% of whole hanging incidents for the researched period). The amount of hanging deaths among juveniles and their percent in the total quantity of deaths from this type of strangulated asphyxia increased in 2017, 2018 and 2019 years to 8 (1.6%), 15 (3.1%) and 18 (3.6%) incidents respectively; decreased in 2020 year to 7 (1.7%) incidents and increased again in 2021 year to 13 (3.0%) incidents. Juveniles died by hanging were mostly male (73.8%) aged from 15 to 18 years (63.9%). The median age for girls was 16 years (IQR 15.0-16.75) and for boys 15 years (IQR 13.0-16.5). Most of juveniles' corps were found in their place of residence: in apartments or residential houses (the whole number was 49 or 80.4%). Generally, juvenile hanging occurred between November and January (36.1% of all incidents) and in April (11.5%); less frequently were in February (1.6%), June and July (9.8%). Alcohol was found in blood of 18.2% juveniles aged from 15 to 18.

Collaborative to Increase Lethal Means Counseling for Caregivers of Youth With Suicidality

BACKGROUND

The number of youth presenting to hospitals with suicidality and/or self-harm has increased substantially in recent years. We implemented a multihospital quality improvement (QI) collaborative from February 1, 2018 to January 31, 2019, aiming for an absolute increase in hospitals' mean rate of caregiver lethal means counseling (LMC) of 10 percentage points (from a baseline mean performance of 68% to 78%) by the end of the collaborative, and to evaluate the effectiveness of the collaborative on LMC, adjusting for secular trends.

METHODS

This 8 hospital collaborative used a structured process of alternating learning sessions and action periods to improve LMC across hospitals. Electronic medical record documentation of caregiver LMC was evaluated during 3 phases: precollaborative, active QI collaborative, and postcollaborative. We used statistical process control to evaluate changes in LMC monthly. Following collaborative completion, interrupted time series analyses were used to evaluate changes in the level and trend and slope of LMC, adjusting for covariates.

RESULTS

In the study, 4208 children and adolescents were included-1314 (31.2%) precollaborative, 1335 (31.7%) during the active QI collaborative, and 1559 (37.0%) postcollaborative. Statistical process control analyses demonstrated that LMC increased from a hospital-level mean of 68% precollaborative to 75% (February 2018) and then 86% (October 2018) during the collaborative. In interrupted time series analyses, there were no significant differences in LMC during and following the collaborative beyond those expected based on pre-collaborative trends.

CONCLUSIONS

LMC increased during the collaborative, but the increase did not exceed expected trends. Interventions developed by participating hospitals may be beneficial to others aiming to improve LMC for caregivers of hospitalized youth with suicidality.

Türkiye'nin batı bölgesinde bir şehirde COVID-19 pandemisi öncesi ve sırasında intihar eğilimlerinin karşılaştırılması

Purpose: This study aims to compare the completed suicides in the early period of the COVID-19 pandemic with the completed suicides in the same time interval immediately before the pandemic in the Manisa Province of Turkey and to investigate whether there are pandemic-specific completed suicide trends. Materials and Methods: The study sample consisted of 162 completed suicides that occurred between January 2019 - February 2020 (pre-pandemic period) and March 2020 - June 2021 (pandemic period) in Manisa Province. Completed suicides were compared in terms of sociodemographic and clinical characteristics. Results: The number of completed suicides before and during the pandemic was 84 and 78, respectively. There was no statistically significant difference between the pre-pandemic and pandemic periods in the number of completed suicides. In terms of sociodemographic characteristics, marital status, contrary to gender, age, employment status, and educational level, caused a significant difference in the number of suicides before and during the pandemic period. Additionally, the season when the completed suicide occurred and the type of place of residence of the individuals with completed suicide, caused a significant difference in the number of suicides Conclusion: The study's findings indicated that the pandemic period was not a factor in general in completed suicides. Specifically, however, it is noteworthy that suicide by hanging was more common during the pandemic period, in the spring season, among individuals who were married, employed, resided in urban areas, had a low educational level, and had a history of psychiatric diseases such as mood disorders.

Trends in suicide deaths before and after the COVID-19 outbreak in Korea

We investigated the effect of the coronavirus disease-2019 (COVID-19) pandemic on suicide trends in Korea via a time-series analysis. We used Facebook Prophet to generate forecasting models based on the monthly numbers of suicide deaths in Korea between 1997 and 2018, validated the models by comparison with the 2019 numbers, and predicted the numbers of suicides in 2020. We compared the expected and observed numbers of suicides during the COVID-19 pandemic. The total numbers of suicides during the COVID-19 pandemic did not deviate from projections based on the pre-pandemic period. However, the number of suicides among women and those under the age of 34 years significantly exceeded the expected level. The COVID-19 pandemic did not increase the overall suicide rate significantly. However, suicides among women and young people increased, suggesting that the pandemic might drive more members of these groups to suicide. Further studies are needed to verify the long-term impact of the COVID-19 pandemic on suicide.

When is pharmacotherapy necessary for the treatment of seasonal affective disorder?

No abstract is required for the editorial.

Seasonal changes in mood and behavior contribute to suicidality and worthlessness in a population-based study

Limited evidence suggests that the seasonal changes in mood and behavior may associate with suicidality and the feelings of worthlessness, but these associations have not been analyzed in large population-based data. A random sample of adults (n = 4069), representative of the general population living in Finland, attended a nationwide health examination survey. Seasonal variations (seasonality) in mood and behavior were analyzed with the six items of global seasonality score (GSS) and the experienced problem due to these variations. Their impact on suicidality as well as on the feelings of worthlessness were analyzed using logistic regression models. After adjusting for age and gender, the GSS, each of its six items and the experienced problem due to the seasonal variations in mood and behavior all showed separately a significant association with suicidality as well as with worthlessness. After further adjustment for the education level and region of residence, the GSS, its mood item and the experienced problem remained significantly associated with both suicidality and worthlessness. Seasonal variations in mood and behavior have a significant association with both suicidality and worthlessness.

Assessing seasonality and the role of its potential drivers in environmental epidemiology: a tutorial

Several methods have been used to assess the seasonality of health outcomes in epidemiological studies. However, little information is available on the methods to study the changes in seasonality before and after adjusting for environmental or other known seasonally varying factors. Such investigations will help us understand the role of these factors in seasonal variation in health outcomes and further identify currently unknown or unmeasured risk factors. This tutorial illustrates a statistical procedure for examining the seasonality of health outcomes and their changes, after adjusting for potential environmental drivers by assessing and comparing shape, timings and size. We recommend a three-step procedure, each carried out and compared before and after adjustment: (i) inspecting the fitted seasonal curve to determine the broad shape of seasonality; (ii) identifying the peak and trough of seasonality to determine the timings of seasonality; and (iii) estimating the peak-to-trough ratio and attributable fraction to measure the size of seasonality. Reporting changes in these features on adjusting for potential drivers allows readers to understand their role in seasonality and the nature of any residual seasonal pattern. Furthermore, the proposed approach can be extended to other health outcomes and environmental drivers.

High temperatures trigger suicide mortality in Brussels, Belgium: A case-crossover study (2002-2011)

BACKGROUND

Temperature may trigger the risk of suicide, however, the extent and shape of the associations show geographical variation. Here, we investigate the short-term effects of temperature on suicide deaths occurring in Brussels between January 1st, 2002 and December 31st, 2011.

METHODS

We conducted a bidirectional time-stratified case-crossover study with cases being suicide deaths occurring among Brussels residents aged 5 years or older. Cases were matched by day of the week with control days from the same month and year. The exposure was the daily average temperature measured at the Uccle station (Brussels) and obtained from the Belgian Royal Meteorological Institute. We combined conditional logistic regression with distributed lag non-linear models (DLNM) to obtain one week (lag 0-6) cumulative risk ratios (RR) and their 95% confidence intervals (CI) for the effects of moderate and extreme cold (5th and 1st percentiles of temperature, respectively) and moderate and extreme heat (95th and 99th percentiles of temperature, respectively), relative to the median temperature.

RESULTS

In total, 1891 suicide deaths were included. The median temperature was 11.6 °C, moderate and extreme cold temperatures were 0 and -3.1 °C, respectively, and moderate and extreme high temperatures were 20.9 and 24.4 °C, respectively. The cumulative risk of suicide mortality was almost twice higher among lags 0 to 6 for both moderate and extreme heat, relative to the period median temperature (e.g. moderate heat RR = 1.80 CI:1.27-2.54). No statistically significant associations were observed for cold temperatures.

CONCLUSIONS

In Brussels, a western European city with temperate climate, high temperatures may trigger suicide deaths up to one week later. In the context of climate change, adaptation strategies must take into consideration the effects of temperature on mental health.

Changing Seasonal Pattern of Suicides in Korea Between 2000 and 2019

OBJECTIVE

This study aimed to investigate the changing seasonal pattern of suicides in Korea between 2000 and 2019.

METHODS

We calculated a seasonal pattern of suicides between 2000 and 2019 using a non-stationary cosinor model. In addition, we estimated the effect of each month on the suicide incidence compared to a reference month, using a generalized linear model with a categorical variable of the month. Then, we visualized the rate ratio curves of suicides by gender, age group, and subperiod.

RESULTS

We observed a seasonal pattern of suicides in Korea with a spring peak and a winter trough. The seasonal ups and downs were most pronounced in suicides among the elderly ≥65 years. However, the seasonal pattern has not been consistent over the past two decades, with lowering seasonal peaks since 2012. The amplitude of seasonality was also lower in 2010-2019 than in 2000-2009.

CONCLUSION

The seasonal pattern of suicides seems to have diminished in Korea in recent years. Thus, we need further studies to investigate climatic and non-climatic factors influencing the seasonality of suicides and the consequence of the change.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study

BACKGROUND

Although seasonal variations in mortality have been recognized for millennia, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature.

METHODS

We compiled daily data on all-cause, cardiovascular and respiratory mortality, temperature and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day of year. Meta-analysis was used to summarize location-specific estimates for each climate zone. We estimated the PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on the PTR across locations by using meta-regression models.

RESULTS

Seasonality estimates and responses to temperature adjustment varied across locations. The unadjusted PTR for all-cause mortality was 1.05 [95% confidence interval (CI): 1.00-1.11] in the tropical zone and 1.23 (95% CI: 1.20-1.25) in the temperate zone; adjusting for temperature reduced the estimates to 1.02 (95% CI: 0.95-1.09) and 1.10 (95% CI: 1.07-1.12), respectively. Furthermore, the unadjusted PTR was positively associated with average mean temperature.

CONCLUSIONS

This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature.

Temporal patterns of suicide and circulatory system disease-related mortality are inversely correlated in several countries

BACKGROUND

Nearly 800,000 suicides occur worldwide annually and suicide rates are increasing faster than population growth. Unfortunately, the pathophysiology of suicide remains poorly understood, which has hindered suicide prevention efforts. However, mechanistic clues may be found by studying effects of seasonality on suicide and other mortality causes. Suicides tend to peak in spring-summer periods and nadir in fall-winter periods while circulatory system disease-related mortality tends to exhibit the opposite temporal trends. This study aimed to determine for the first time whether monthly temporal cross-correlations exist between suicide and circulatory system disease-related mortality at the population level. If so and if common biological factors moderate risks for both mortality types, such factors may be discoverable and utilized to improve suicide prevention.

METHODS

We conducted time series analyses of monthly mortality data from northern (England and Wales, South Korea, United States) and southern (Australia, Brazil) hemisphere countries during the period 2009-2018 (N = 41.8 million all-cause mortality cases). We used a Poisson regression variant of the standard cosinor model to determine peak months of mortality. We also estimated cross-correlations between monthly mortality counts from suicide and from circulatory system diseases.

RESULTS

Suicide and circulatory disease-related mortality temporal patterns were negatively correlated in Australia (- 0.32), Brazil (- 0.57), South Korea (- 0.32), and in the United States (- 0.66), but no temporal correlation was discernable in England and Wales.

CONCLUSIONS

The negative temporal cross-correlations between these mortality types we found in 4 of 5 countries studied suggest that seasonal factors broadly and inversely moderate risks for circulatory disease-related mortality and suicide, but not in all regions, indicating that the effect is not uniform. Since the seasonal factors of temperature and light exert opposite effects on suicide and circulatory disease-related mortality in several countries, we propose that physiologically-adaptive circulatory system responses to heat and light may increase risk for suicide and should be studied to determine whether they affect suicide risk. For example, heat and light increase production and release of the bioactive gas nitric oxide and reduce circulatory system disease by relaxing blood vessel tone, while elevated nitric oxide levels are associated with suicidal behavior, inverse effects that parallel the inverse temporal mortality patterns we detected.

Meteorological Variables and Suicidal Behavior: Air Pollution and Apparent Temperature Are Associated With High-Lethality Suicide Attempts and Male Gender

This study analyzed the impact of meteorological variables and high-lethality suicide attempts (HLSA) to assess a potential time shift of HLSA affected by climate evolution to predict the suicide attempt cases over different periods of the year. After attempting suicide, 225 subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the psychiatric unit from March 2016 to July 2018. Socio-demographic and clinical characteristics as well as the meteorological variables were collected. The Mann-Kendall test as well as redundancy and cross-correlation analyses were performed to analyze the trends, statistically correlations, and correspondence of the trends, respectively between suicidal behaviors and climatic factors. Sixty-seven (29.8%) committed a HLSA. Our findings indicate a significant association between HLSA and male gender and apparent temperature with a strong correlation of 75% with a phase shift of -1 month. Solar radiation and air pollution (PM_2.5) have a positive correlation of 65 and 32%, respectively, with a zero-time lag. Limitations include that the data are limited to a single hospital; psychological factors, or other clinical variables that could be ruled out as a trigger have not been considered. Meteorological variables may not mirror the temperature that the patient is exposed to due to the air conditioning systems. Exploring those environmental factors associated with HLSA in a more detailed manner could lead to early intervention and prevention strategies for such distressing admissions.