Relationship between daylength and suicide in Finland

Daylight saving time was not associated with a change in suicide rates in Austria, Switzerland and Sweden

BACKGROUND

Some studies have reported an increase in suicides after the start of daylight saving time (DST), but the evidence is mixed and more research about proposed mechanisms (disrupted sleep, changing light exposure) is needed.

METHODS

In our preregistered study, we analyzed change in suicide rates in the 2 weeks before/after DST, based on data between 1980 and 2022 from Austria, Switzerland and Sweden, using Poisson regression models and changepoint analyses. To explore the impact of disrupted sleep, we repeated the analysis for retired people who are likely less bound to DST, and for younger people. To explore the effect of changed daylight exposure, we repeated the analysis for northern and southern regions because twilight and daylight exposure varies by latitude.

RESULTS

Suicide rates did not significantly increase after the start of DST (adjusted incidence rate ratio IRR = 0.98, 95% CI 0.91-1.06, P = 0.66, n = 13 362 suicides) or after DST ended (adjusted IRR = 0.99, 95% CI 0.91-1.07, P = 0.76, n = 12 319 suicides). There were no statistically significant findings among younger or older subgroups and also not in Sweden and Austria/Switzerland. No changepoints were detected.

CONCLUSIONS

There were no significant changes in suicide rates associated with DST and no clear evidence to support proposed mechanisms (light exposure, disruption of sleep). Our study is one of the largest and was adequately powered. Nonetheless, even larger studies to detect smaller effects could be important to inform the debate about harms and benefits of DST.

Pattern of encounters to emergency departments for suicidal attempts in France: Identification of high-risk days, months and holiday periods

INTRODUCTION

Seasonal change in patterns of suicidal attempts is not well known in France and may differ from other western countries. We aimed to determine the peak times (days, months and holiday periods) of suicidal attempts in France.

METHODS

We carried out a multicentre retrospective epidemiological study, using data from the Organization for Coordinated Monitoring of Emergencies (OSCOUR®) network. We aggregated daily data from January 1, 2010, to December 31, 2019. Variations in suicidal attempts on specific days were investigated by comparing their frequencies (ad hoc Z-scores).

RESULTS

114,805,488 ED encounters were recorded including 233,242 ED encounters regarding suicidal attempts. Men accounted for 45.7%. A significantly higher frequency of ED encounters for suicidal acts were found on Sundays in the months of May-June for both sexes and on New Year's Day for all genders and age groups. An increased risk was also noted on July 14th (National Day) and June 22nd (Summer Solstice). A protective effect was noted on the day after Valentine's Day, on Christmas Day and Christmas time (in particular December 24 and 26).

CONCLUSION

Sundays, June, New Year's Day were at increased risk of suicidal attempts in France requiring a strengthening of prevention.

Association between provincial sunshine duration and mortality rates in China: Panel data study

Background

mortality rates are usually influenced by the variations of environmental factors. However, there are few studies on the impact of sunlight duration induced mortality. In this study, we examine provincial level associations between the sunshine duration and crude mortality rates.

Methods

we use China mortality data from the National Bureau of Statistics of China combined with China census data and data from the China Meteorological Data Service Centre. Annual mortality rates for 31 provinces, autonomous regions, and municipalities in China from 2005 to 19. Data are analyzed at the provincial level by using panel regression methods. The main outcome measures are the mortality rates associated with average daily sunshine duration. Then we perform a series of sentimental analyses.

Results

the average daily sunshine duration ratio cubed is positively associated with provincial level mortality rates (β = 11.509, 95% confidence interval 1.869 to 21.148). According to this estimate, increasing 2.895 h of additional daily sunshine is associated with an estimated 1.15% increase in the crude mortality rates. A series of sensitivity analyses show a consistent pattern of associations between average daily sunshine duration ratio cubed and mortality rates.

Conclusions

more sunshine duration is associated with increased mortality rates. While the associations documented cannot be assumed to be causal, they suggest a potential association between increased sunshine duration and increased mortality rates.

Effect of Ketamine on Sleep in Treatment-Resistant Depression: A Systematic Review

BACKGROUND

Depression is a debilitating disease with a high socioeconomic burden. Regular antidepressants usually require several weeks to ameliorate symptoms; however, numerous patients do not achieve remission. What is more, sleep disturbances are one of the most common residual symptoms. Ketamine is a novel antidepressant with rapid onset of action with a proven antisuicidal effect. Little is known about its impact on sleep-wake and circadian rhythm alterations. The aim of this systematic review is to research the impact ketamine has on sleep disturbances in depression.

METHODS

PubMed, Web of Science, and APA PsycINFO were searched for relevant studies on ketamine's impact on sleep disturbances in depression. Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA2020 methodology was applied. The systematic review protocol was registered in the PROSPERO Registry (CRD42023387897).

RESULTS

Five studies were included in this review. Two studies reported significant improvement in sleep measured by MADRS (Montgomery-Åsberg Depression Rating Scale) and QIDS-SR16 (Quick Inventory of Depressive Symptomatology Self-Report (16-item)) scales after intravenous ketamine and intranasal esketamine administration. One case report showed mitigation of symptoms in PSQI (Pittsburgh Sleep Quality Index) and ISI (Insomnia Severity Index) during 3-month treatment with esketamine. In two studies, sleep was objectively measured by nocturnal EEG (electroencephalography) and showed a decrease in nocturnal wakefulness accompanied by an increase in slow wave (SWS) and rapid eye movement (REM) sleep.

CONCLUSION

Ketamine reduces the severity of sleep insomnia in depression. Robust data are lacking. More research is needed.

Impact of the COVID-19 Pandemic on Adolescent Self-Harm: Based on a National Emergency Department Information System

Republic of Korea's suicide rate is the highest among Organization for Economic Co-operation and Development countries. In Republic of Korea, suicide is the leading cause of death among young people aged 10-19 years. This study aimed to identify changes in patients aged 10-19 years who visited the emergency department in Republic of Korea after inflicting self-harm over the past five years and to compare the situations before and after the outbreak of the COVID-19 pandemic. Analysis of government data revealed that the average daily visits per 100,000 were 6.25, 8.18, 13.26, 15.31, and 15.71 from 2016 to 2020, respectively. The study formed four groups for further analysis, with the population divided by sex and age (10-14 and 15-19 years old). The late-teenage female group showed the sharpest increase and was the only group that continued to increase. A comparison of the figures 10 months before and after the outbreak of the pandemic revealed a statistically significant increase in self-harm attempts by only the late-teenage female group. Meanwhile, visits (per day) in the male group did not increase, but the rates of death and ICU admission increased. Additional studies and preparations that account for age and sex are warranted.

Short-term changes in meteorological conditions and suicide: A systematic review and meta-analysis

BACKGROUND

Suicide is a leading cause of death, particularly for young adults. Suicidal behaviours are influenced by a wide-range of personal, social, and cultural factors. Emerging evidence suggests that daily changes in meteorological conditions, including temperature, increases the risk of suicide.

METHODS

We conducted a systematic review and meta-analysis of studies that examined associations between either daily, or weekly, variations for eight meteorological variables and suicide outcomes (attempts, or deaths). Meta-analytic methods were applied to derive summary measures of association using random effect models. We assessed the heterogeneity in these associations by region and biological sex.

RESULTS

We identified 29 studies of suicide. Of these, 26 reported associations between temperature, while fewer studies reported on rain (n = 4), solar radiation (n = 4), humidity (n = 3), sunshine (n = 3), atmospheric pressure (n = 2), wind (n = 2) and cloud cover (n = 2). The overall relative risk for suicide deaths/attempts per 1 °C increase in ambient temperature was 1.016 (95% CI: 1.013-1.019). Subgroup analysis of temperature found stronger associations with suicide when using the maximum rather than the mean daily temperature, among men, and for completed suicides relative to attempts. Regionally, the strongest associations were found in the East Asia and Pacific region. While associations were found for solar radiation and cloud coverage and suicide, we did not undertake a meta-analysis for these exposures as it was not possible to standardize measures of association across studies. Statistically significant associations were not observed for other identified meteorological variables.

CONCLUSIONS

Our findings suggest that daily increases in temperature increase the risk of suicide, particularly, among men and in the East Asia and Pacific region.

Suicides during the Swedish midsummer holiday: analysis of cause of death data 1980-2018

INTRODUCTION

Previous studies have demonstrated increased suicide rates on holidays such as New Year, nationally and internationally. Comparable to New Year's Eve, Swedish Midsummer is a major holiday, linked to high levels of alcohol consumption in the population. We, therefore, hypothesized that suicides and deaths with undetermined intent would increase during the Midsummer celebration.

METHODS

We used a retrospective death registry design to investigate all suicides that occurred on Midsummer's Eve (ME), Midsummer's Day (MD) and 28 adjacent days (AD) during 1980-2018. Data were stratified by diagnosis type, sex and age, and was analyzed with paired t-tests, Poisson regression, and time-series charts with 95% confidence intervals.

RESULTS

During the 30-day investigation period, the observed average was 4.3 deaths per day (23.3% cases with undetermined intent). ME, but not MD, was associated with significantly fewer suicides compared to AD (-1.08 deaths, p < .01). ME, but not MD, was simultaneously associated with more deaths with undetermined intent (+0.58 deaths, p = .007). No moderating sex or age effects were found. Descriptive statistics showed that poisonings, drownings and traffic-related injuries were common among the undetermined ME cases.

DISCUSSION

The study found that suicide decreases and deaths with undetermined intent increases on ME. The findings are interpreted considering that substance use may affect both suicidal intentions and diagnosis classifications. Social and cultural support and holiday anticipations might also account for suicidal behaviors on ME.

Fluctuations in influenza-like illness epidemics and suicide mortality: A time-series regression of 13-year mortality data in South Korea

AIMS

We explored the association between influenza epidemic and suicide mortality rates in a large population using a time-series regression of 13-year mortality data in South Korea.

METHODS

Weekly suicide mortalities and influenza-like illness (ILI) were analyzed using time series regression. Regression coefficient for suicide mortality based on percentage change of ILI was calculated using a quasi-Poisson regression. Non-linear distributed lag models with quadratic function up to 24 weeks were constructed.

RESULTS

The association between ILI and suicide mortality increased significantly up to 8 weeks post-influenza diagnosis. A significant positive association between ILI and suicide mortality was observed from 2009, when a novel influenza A(H1N1)pdm09 virus provoked a worldwide pandemic. No meaningful association between these factors was observed before 2009.

CONCLUSION

There was a significant positive relationship between ILI and suicide mortality after 2009, when a novel influenza A(H1N1)pdm09 virus provoked a worldwide pandemic.

Fluctuations in influenza-like illness epidemics and suicide mortality: A time-series regression of 13-year mortality data in South Korea

AIMS

We explored the association between influenza epidemic and suicide mortality rates in a large population using a time-series regression of 13-year mortality data in South Korea.

METHODS

Weekly suicide mortalities and influenza-like illness (ILI) were analyzed using time series regression. Regression coefficient for suicide mortality based on percentage change of ILI was calculated using a quasi-Poisson regression. Non-linear distributed lag models with quadratic function up to 24 weeks were constructed.

RESULTS

The association between ILI and suicide mortality increased significantly up to 8 weeks post-influenza diagnosis. A significant positive association between ILI and suicide mortality was observed from 2009, when a novel influenza A(H1N1)pdm09 virus provoked a worldwide pandemic. No meaningful association between these factors was observed before 2009.

CONCLUSION

There was a significant positive relationship between ILI and suicide mortality after 2009, when a novel influenza A(H1N1)pdm09 virus provoked a worldwide pandemic.

Seasonal Variation in the Brain μ-Opioid Receptor Availability

Seasonal rhythms influence mood and sociability. The brain μ-opioid receptor (MOR) system modulates a multitude of seasonally varying socioemotional functions, but its seasonal variation remains elusive with no previously reported in vivo evidence. Here, we first conducted a cross-sectional study with previously acquired human [¹¹C]carfentanil PET imaging data (132 male and 72 female healthy subjects) to test whether there is seasonal variation in MOR availability. We then investigated experimentally whether seasonal variation in daylength causally influences brain MOR availability in rats. Rats (six male and three female rats) underwent daylength cycle simulating seasonal changes; control animals (two male and one female rats) were kept under constant daylength. Animals were scanned repeatedly with [¹¹C]carfentanil PET imaging. Seasonally varying daylength had an inverted U-shaped functional relationship with brain MOR availability in humans. Brain regions sensitive to daylength spanned the socioemotional brain circuits, where MOR availability peaked during spring. In rats, MOR availabilities in the brain neocortex, thalamus, and striatum peaked at intermediate daylength. Varying daylength also affected the weight gain and stress hormone levels. We conclude that cerebral MOR availability in humans and rats shows significant seasonal variation, which is predominately associated with seasonal photoperiodic variation. Given the intimate links between MOR signaling and socioemotional behavior, these results suggest that the MOR system might underlie seasonal variation in human mood and social behavior.SIGNIFICANCE STATEMENT Seasonal rhythms influence emotion and sociability. The central μ-opioid receptor (MOR) system modulates numerous seasonally varying socioemotional functions, but its seasonal variation remains elusive. Here we used positron emission tomography to show that MOR levels in both human and rat brains show daylength-dependent seasonal variation. The highest MOR availability was observed at intermediate daylengths. Given the intimate links between MOR signaling and socioemotional behavior, these results suggest that the MOR system might underlie seasonal variation in human mood and social behavior.

Seasonality of Suicides among Victims Who Are under the Influence of Alcohol

Introduction: Suicide is one of the most frequent causes of death. According to the World Health Organization (WHO), each year, over eight hundred thousand people worldwide die as a result of suicide. The most common risk factors for suicide are depressive disorders and alcohol dependence. Alcohol can directly influence a decision about suicide, or be a factor facilitating this decision. The aim of the study was to analyse the seasonality of suicides among persons under the influence of alcohol. Material and Methods: Data for analysis were obtained from the Department of Forensic Medicine (DFM) of the Medical University of Warsaw. A retrospective analysis was performed on 317 victims of suicides by hanging, those which were entered into the registry of deaths kept by the DFM in the years 2009–2013. The analysis took into account the age and sex of victims, initial cause of death, date of post-mortem examination, autopsy result and alcohol concentration in the blood or muscles of the victims. Statistical analysis was performed using IBM SPSS Statistics version 20. Results: In the analysis, a spring peak of suicides was found for men, and an autumn peak was revealed for women. In addition, a significant correlation was observed between the age of victims and the concentration of alcohol; the older the victims, the higher the alcohol concentration. However, this correlation was reported only in the spring months. Conclusions: The results of the analysis seem to be consistent with seasonal patterns observed in other studies, and they indicate the occurrence of suicide seasonality. In order to improve the strategies of suicide prevention, it is necessary to identify factors which are related to the seasonal variation of suicidal behaviours, as well as to gain knowledge about the mechanisms behind this phenomenon.

Epidemiology of Suicidal Behavior in Malaga (Spain): An Approach From the Prehospital Emergency Service

Objective: This study aims to analyse the number and characteristics of calls made to the Málaga Prehospital Emergency Service (PES) for suicidal behavior based on sociodemographic, temporal, and health care variables. Method: This is a retrospective, descriptive study that records all calls made to the PES due to suicidal behavior (suicide attempts and completed suicides) in 2014. Sociodemographic variables (age, sex, and health district), variables related to the calls (time-slot, degree of sunlight, type of day, month, season of the year, prioritization, and number of resources mobilized) were extracted from these calls. The number of cases and percentages were presented for the qualitative variables. The rates per 100,000 were calculated by sex and health district and presented with the corresponding 95% confidence interval (CI). Results: Of the total valid calls to PES (n = 181,824), 1,728 calls were made due to suicidal behavior (0.9%). The mean age was 43.21 (±18) years, 57.4% were women, and the rate was 112.1 per 100,000 inhabitants. The calls due to suicidal behavior were in the younger-middle age segment, in the time-slot between 16 and 23 h and during daylight hours, on bank holidays, in spring and summer in comparison with winter, and with a peak of calls in August. The majority of these calls were classified as undelayable emergencies and mobilized one health resource. Conclusions: Prehospital emergency services are the first contact to the sanitary services of persons or families with suicide attempts. This information should be a priority to offer a complete overview of the suicide behavior.

Epidemiology of Suicide and the Psychiatric Perspective

Suicide is a worldwide phenomenon. This review is based on a literature search of the World Health Organization (WHO) databases and PubMed. According to the WHO, in 2015, about 800,000 suicides were documented worldwide, and globally 78% of all completed suicides occur in low- and middle-income countries. Overall, suicides account for 1.4% of premature deaths worldwide. Differences arise between regions and countries with respect to the age, gender, and socioeconomic status of the individual and the respective country, method of suicide, and access to health care. During the second and third decades of life, suicide is the second leading cause of death. Completed suicides are three times more common in males than females; for suicide attempts, an inverse ratio can be found. Suicide attempts are up to 30 times more common compared to suicides; they are however important predictors of repeated attempts as well as completed suicides. Overall, suicide rates vary among the sexes and across lifetimes, whereas methods differ according to countries. The most commonly used methods are hanging, self-poisoning with pesticides, and use of firearms. The majority of suicides worldwide are related to psychiatric diseases. Among those, depression, substance use, and psychosis constitute the most relevant risk factors, but also anxiety, personality-, eating- and trauma-related disorders as well as organic mental disorders significantly add to unnatural causes of death compared to the general population. Overall, the matter at hand is relatively complex and a significant amount of underreporting is likely to be present. Nevertheless, suicides can, at least partially, be prevented by restricting access to means of suicide, by training primary care physicians and health workers to identify people at risk as well as to assess and manage respective crises, provide adequate follow-up care and address the way this is reported by the media. Suicidality represents a major societal and health care problem; it thus should be given a high priority in many realms.

Solar radiation increases suicide rate after adjusting for other climate factors in South Korea

OBJECTIVE

Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea.

METHOD

Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM.

RESULTS

Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m² after adjusting for other confounding climate factors (P < 0.001).

CONCLUSION

Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends.

Ketamine-Induced Glutamatergic Mechanisms of Sleep and Wakefulness: Insights for Developing Novel Treatments for Disturbed Sleep and Mood

Ketamine, a drug with rapid antidepressant effects and well-described effects on slow wave sleep (SWS), is a useful intervention for investigating sleep-wake mechanisms involved in novel therapeutics. The drug rapidly (within minutes to hours) reduces depressive symptoms in individuals with major depressive disorder (MDD) or bipolar disorder (BD), including those with treatment-resistant depression. Ketamine treatment elevates extracellular glutamate in the prefrontal cortex. Glutamate, in turn, plays a critical role as a proximal element in a ketamine-initiated molecular cascade that increases synaptic strength and plasticity, which ultimately results in rapidly improved mood. In MDD, rapid antidepressant response to ketamine is related to decreased waking as well as increased total sleep, SWS, slow wave activity (SWA), and rapid eye movement (REM) sleep. Ketamine also increases brain-derived neurotrophic factor (BDNF) levels. In individuals with MDD, clinical response to ketamine is predicted by low baseline delta sleep ratio, a measure of deficient early night production of SWS. Notably, there are important differences between MDD and BD that may be related to the effects of diagnosis or of mood stabilizers. Consistent with its effects on clock-associated molecules, ketamine alters the timing and amplitude of circadian activity patterns in rapid responders versus non-responders with MDD, suggesting that it affects mood-dependent central neural circuits. Molecular interactions between sleep homeostasis and clock genes may mediate the rapid and durable elements of clinical response to ketamine and its active metabolite.

Nocturnal Wakefulness Is Associated With Next-Day Suicidal Ideation in Major Depressive Disorder and Bipolar Disorder

OBJECTIVE

Self-reported sleep disturbances may confer elevated risk for suicidal ideation, suicide attempts, and death. However, limited research has evaluated polysomnographically determined sleep disturbance as an acute physiologic risk factor for suicidal thoughts. This study sought to investigate the relationship between nocturnal wakefulness in association with next-day suicidal ideation using overnight polysomnography assessment from data collected between 2006 and 2013.

METHODS

Sixty-five participants with DSM-IV-diagnosed major depressive disorder or bipolar depression underwent overnight polysomnography monitoring in a sleep laboratory. The Hamilton Depression Rating Scale (HDRS) was administered the morning after polysomnography recording to assess next-day suicidal ideation, severity of depressive symptoms, and subjective sleep disturbances.

RESULTS

Using a generalized linear mixed model, a significant time-by-ideation interaction was found indicating greater nocturnal wakefulness at 4:00 am among participants with suicidal ideation (F4,136 = 3.65, P = .007). Increased time awake during the 4:00 am hour (4:00 to 4:59) was significantly associated with elevated suicidal thoughts the next day (standardized β = 0.31, P = .008). This relationship persisted after controlling for age, gender, diagnosis, and severity of depressive symptoms.

CONCLUSIONS

Greater nocturnal wakefulness, particularly in the early morning hours, was significantly associated with next-day suicidal thoughts. Polysomnographically documented sleep disruption at specific times of night may represent an acute risk factor of suicidal ideation that warrants additional research.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00024635.

Seasonality of suicide behavior in Northwest Alaska: 1990-2009

OBJECTIVES

Suicide is a leading cause of death worldwide, and disproportionately affects Indigenous populations. Seasonal suicide patterns are variable in the literature, and could offer novel approaches to the timing and focus of prevention efforts if better understood. With a suicide surveillance system in place since 1989, this study offers an unprecedented opportunity to explore seasonal variations in both fatal and non-fatal suicide behavior in an Indigenous Arctic region.

STUDY DESIGN

Cross-sectional.

METHODS

In this descriptive study, we analyzed data collected from 1990 to 2009 in the rural northwest region of Alaska, both graphically and using the chi-squared test for multinomials.

RESULTS

We found a significant monthly variation for suicide attempts, with a peak in suicide behavior observed between April and August (P = 0.0002). Monthly variation was more pronounced among individuals ≤29 years of age, and was present in both males and females, although the seasonal pattern differed by sex.

CONCLUSIONS

Our findings of a significant seasonal pattern in suicide behavior, with monthly variation (summer peak) in non-fatal suicide behavior among younger age groups, and among both males and females can assist planners in targeting subpopulations for prevention at different times of the year.

Does suicide have a stronger association with seasonality than sunlight?

OBJECTIVES

Suicide rates have widely been reported to peak in spring and summer. A frequent hypothesis is that increased sunlight exposure alters biological mechanisms. However, few attempts have been made to systematically untangle the putative suicidogenic risk of sunlight exposure from that of seasonality. We examined whether average hours of daily sunlight in a month confer additional risk over month of year when predicting monthly suicide rates.

DESIGN

Historical population-based ecological longitudinal study.

SETTING AND PARTICIPANTS

We used 3 longitudinal studies (n=31,060 suicides) with monthly suicide and meteorological data from Greece (1992-2001), Victoria, Australia (1990-1998) and Norway (1969-2009).

INTERVENTION

We used a negative binomial regression to observe (1) the association of month of year with suicides, adjusting for different sunlight exposures, and (2) the association of sunlight exposure with suicides, adjusting for month of year. We then investigated claims that suicides were associated with daily sunlight exposures, defined by us as 2550 sunlight exposure combinations corresponding to a 1-50 days exposure window with lags of 0-50 days.

RESULTS

Using monthly data, the association between month of year and suicides remained after adjusting for mean daily hours of sunlight and change in the mean daily hours of sunlight. Adjusted for month of year, the associations between sunlight exposure and suicides became non-significant and attenuated towards the null (the coefficient estimate for mean daily hours of sunlight decreased in absolute magnitude by 72%). The findings were consistent across all 3 cohorts, both when analysed separately and combined. When investigating daily sunlight exposures, we found no significant results after correcting for multiple testing.

CONCLUSIONS

Using monthly data, the robustness of our month of year effects, combined with the transient and modest nature of our sunlight effects, suggested that the association between sunlight exposure and suicide was a proxy for the association between seasonality and suicide.

Suicide attempts and emergency room psychiatric consultation

BACKGROUND

Suicidal behaviours are major public health concerns worldwide. They are associated with risk factors that vary with age and gender, occur in combination, and may change over time. The aim of our study was to investigate how frequently patients visiting a hospital emergency room (ER) require a psychiatric consultation for attempted suicide, and to outline the characteristics of this population.

METHODS

Determinants of emergency room visits for psychiatric reasons were studied prospectively from 2008 to 2011 at the "Maggiore" Hospital in Novara.

RESULTS

280 out of 1888 patients requiring psychiatric consultation were referred to the ER because of suicide attempt. Suicide attempters were more often female. The rate of suicide attempters among Italian people was 14.2%, compared to 19.5% in foreigners. Subjects living with parents or own family and those having a permanent job had a higher frequency of suicide attempt. Suicide attempts were more frequent among patients with a history of psychiatric disorders; nonetheless, suicide attempts were more common among those who had not previously been hospitalized in a psychiatric ward or were not under the care of a psychiatrist. The multivariate analysis found that female gender was a risk factor for suicide attempt, while being in the colder months of the year and, surprisingly, unemployment were protective factors.

CONCLUSIONS

A better understanding of patients referring to the ER due to attempted suicide may allow the identification of at-risk subjects and the implementation of targeted treatment approaches.

Local daily temperatures, thermal seasons, and suicide rates in Finland from 1974 to 2010

OBJECTIVES

Suicide peaks in late spring and October are still seen in Finland among many countries. Weather factors have been suggested as explanations for these peaks, although with inconsistent results. Since the exact timing of these peaks varies each year, the length of daylight and changes in it seem inadequate as an explanation. We hypothesized that ambient temperature and the timing of thermal seasons might associate with suicide rate.

METHODS

Suicide rates from three areas across Finland (N = 10,802) were analyzed with Poisson regression in six different models against variables calculated from the local ambient daily temperature, diurnal temperature range, and the duration from the onset of thermal seasons. Separate models for men and women were constructed.

RESULTS

The temperature change over 5 days associated with the suicide rate of men in Helsinki region, or in other words, the lower the suicide rate was, the higher the temperature decrease had been. For women, the results were more inconsistent.

CONCLUSIONS

Our study is in line with some earlier studies which imply that impairment of thermoregulation might exist among suicide victims.

Seasonal variation in suicidal behavior with prescription opioid medication

BACKGROUND

Suicide attempts by self-poisoning utilizing prescription opioids account for more than half of prescription drug abuse and misuse emergency calls received by poison centers. Additionally seasonal suicidal behavior using other means is a commonly replicated finding. We hypothesized seasonal behavior would exist in individuals using opioid medication as a suicide means, and that this pattern would change at different latitudes in the United States.

METHODS

We used a harmonic regression strategy to investigate sinusoidal seasonal variations of suicidal behavior utilizing prescription opioids, and to contrast changes in seasonal behavior by latitude within the United States. Further, we investigated associations between suicide frequency utilizing opioid medication and frequency of dispensed opioid prescriptions.

RESULTS

Seasonal patterns were identified; overall, all harmonic terms were significant (p<0.05). Interaction terms of harmonic by latitude and harmonic by gender also were significant (p<0.05). After stratification, females had significant harmonic terms at all latitudes. A changing peak time period with latitude also was observed, such that the peak appeared later at more southern latitudes. Additionally, increased dispensed prescriptions rates per population were associated with increased suicidal behavior utilizing prescription opioids.

LIMITATIONS

This study has limitations due to its ecological nature and to missing data that may inform our understanding of suicide risk factors, such as marital status and socio-economic status.

CONCLUSION

Suicidal behavior with prescription opioids follows a seasonal pattern that changes with latitude within the United States. Further, increased accessibility may contribute to increased suicidal attempt rates utilizing prescription opioids.

Variation and seasonal patterns of suicide mortality in Finland and Sweden since the 1750s

OBJECTIVES

Suicide mortality varies in both the short and long term. Our study examines suicide mortality in Finland and Sweden from the 1750s until today. The aim of our study is to detect any seasonal peaks in suicide rates and examine their temporal evolution to suggest a mechanism that may explain such peaks.

METHOD

We acquired the study material from the Finnish and Swedish cause of death statistics (257,341 deaths by suicide) and the relevant population gender structure data. We then separately calculated the annual male and female suicide rates per 100,000 inhabitants. We analysed the suicide peaks, calculating factors of proportionality for the available data by dividing the suicide rates in the peak months (May and October) by the annual suicide rates.

RESULTS

Suicide rates in Finland and Sweden peak twice a year. Both men and women in both countries most often commit suicide in May. There is another peak in October, with the exception of Finnish men. These suicide peaks coincide with a temperature increase in May and the biggest annual drop in temperature in October. We also observed a monotonic long-term change in the Swedish statistics, but not in the Finnish data. Our hypothesis is that seasonal variation in suicide rates may be caused by abrupt temperature changes twice a year that trigger the activity in brown adipose tissue and deepen depression.

CONCLUSION

While the overall suicide mortality rates varied considerably, the monthly proportions in May did not. This finding suggests a routine factor underlying the spring peak in suicide mortality.

Hypothesis: Cryptochromes and Brown Fat are Essential for Adaptation and Affect Mood and Mood-Related Behaviors

Solar radiation and ambient temperature have acted as selective physical forces among populations and thereby guided species distributions in the globe. Circadian clocks are universal and evolve when subjected to selection, and their properties contribute to variations in fitness within specific environments. Concerning humans, as compared to the remaining, the "evening owls" have a greater deviation from the 24 h cycle, are under a greater pressure to circadian desynchrony and more prone to a cluster of health hazards with the increased mortality. Because of their position in the hierarchy and repressive actions, cryptochromes are the key components of the feedback loops on which circadian clocks are built. Based on the evidence a new hypothesis is formulated in which brown adipocytes with their cryptochromes are responsive to a broad range of physical stimuli from the habitat and through their activity ensure adaptation of the individual. The over-activated brown adipose tissue with deficient cryptochromes might induce disrupted thermoregulation and circadian desynchrony, and thereby contribute to lowered mood and pronounced depressive behaviors.

Atmospheric pressure and suicide attempts in Helsinki, Finland

The influence of weather on mood and mental health is commonly debated. Furthermore, studies concerning weather and suicidal behavior have given inconsistent results. Our aim was to see if daily weather changes associate with the number of suicide attempts in Finland. All suicide attempts treated in the hospitals in Helsinki, Finland, during two separate periods, 8 years apart, were included. Altogether, 3,945 suicide attempts were compared with daily weather parameters and analyzed with a Poisson regression. We found that daily atmospheric pressure correlated statistically significantly with the number of suicide attempts, and for men the correlation was negative. Taking into account the seasonal normal value during the period 1971-2000, daily temperature, global solar radiation and precipitation did not associate with the number of suicide attempts on a statistically significant level in our study. We concluded that daily atmospheric pressure may have an impact on suicidal behavior, especially on suicide attempts of men by violent methods (P < 0.001), and may explain the clustering of suicide attempts. Men seem to be more vulnerable to attempt suicide under low atmospheric pressure and women under high atmospheric pressure. We show only statistical correlations, which leaves the exact mechanisms of interaction between weather and suicidal behavior open. However, suicidal behavior should be assessed from the point of view of weather in addition to psychiatric and social aspects.

Seasonality of suicidal behavior

A seasonal suicide peak in spring is highly replicated, but its specific cause is unknown. We reviewed the literature on suicide risk factors which can be associated with seasonal variation of suicide rates, assessing published articles from 1979 to 2011. Such risk factors include environmental determinants, including physical, chemical, and biological factors. We also summarized the influence of potential demographic and clinical characteristics such as age, gender, month of birth, socioeconomic status, methods of prior suicide attempt, and comorbid psychiatric and medical diseases. Comprehensive evaluation of risk factors which could be linked to the seasonal variation in suicide is important, not only to identify the major driving force for the seasonality of suicide, but also could lead to better suicide prevention in general.