The role of seasonality and photoperiod on the lethality of suicide attempts: A case-control study

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.

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.

Prevention of suicides associated with global warming: perspectives from early career psychiatrists

Climate change poses significant challenges to global mental health, with potential consequences including increased rates of suicide and mental health disorders. Early Career Psychiatrists (ECPs) play a crucial role in addressing these challenges. The Climate Psychiatry Alliance, a group of psychiatrists dedicated to improving mental health amidst climate change, recognizes the importance of cultivating climate-aware ECPs. Training ECPs to become confident climate-aware clinicians enables them to effectively treat patients experiencing anxiety, depression, and PTSD in the context of climate-related distress. Together with other mental health professionals, ECPs can contribute to efforts by implementing strategies for monitoring and treating mental health problems arising from climate events. Additionally, they can raise awareness about the psychological consequences and risks of suicide associated with climate change. Collaboration among ECPs from various regions is essential in developing community-based approaches and reducing vulnerabilities. ECPs must prioritize supporting vulnerable populations by advocating for increased funding for mental health support and research in affected areas. Long-term solutions to address the mental health impacts of climate change and global warming should be pursued to mitigate future suicidality. Integrating climate considerations into local mental health programs and expanding psychological support services is crucial. By promoting emotional resilience and self-awareness, ECPs can contribute to building a more climate-resilient and mentally healthy society.

A Systematic Review on the Impact of Seasonality on Severe Mental Illness Admissions: Does Seasonal Variation Affect Coercion?

Coercion in psychiatry is associated mainly with involuntary admissions. The purpose of this study was to investigate the associations between hospital admissions of patients suffering from affective and schizophrenic disorders and seasonality. A systematic literature search using PubMed, Scopus and Google Scholar was conducted, including studies with affective and schizophrenia disorder admissions, published from October 1992 to August 2020. A total of 31 studies were included in the review. Four broad severe mental illness admission categories were identified regarding seasonality: affective disorders, schizophrenia disorders, involuntary admission affective disorders and involuntary admission schizophrenia disorders. There was clear and strong evidence for spring and summer peaks for severe mental illness admissions; data provided for age, gender and involuntary admissions was limited. Seasonality may have a significant effect on the onset and exacerbation of psychopathology of severe mental illness and should be considered as a risk factor in psychiatric admissions, violence and the risk of mental health coercion. A better understanding of the impact of seasonality on severe mental illness will help professionals to provide the best practices in mental health services in order to reduce and prevent psychiatric hospitalizations (especially involuntary admissions) resulting in further coercive measures.

C-Reactive Protein as a Potential Peripheral Biomarker for High-Lethality Suicide Attempts

The aim of the present study was to identify a cut-off of c-reactive protein (c-RP) potentially predictive of high-lethality suicide attempts (SA) in an inpatient psychiatric sample. After attempting suicide, subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the section of Psychiatry from 1 August 2013 to 31 July 2018. C-reactive protein was measured. The Area Under the Receiver Operating Characteristic (ROC_AUC) was used to assess the discriminative capacity of c-RP for high- vs. low-lethality SA, and a logistic regression was performed to detect the odds ratio, adjusted for age and sex. High-lethality suicide attempters were 133 (30.8%), while low-lethality suicide attempters were 299 (69.2%). The optimal cut-off threshold (and corresponding sensitivity and specificity values) for c-RP was 4.65 mg/L (68/71%). This cut-off corresponds to an AUC of 73.5%. An odds ratio of 4.70 was generated for current high-lethality SA after a logistic regression, adjusted for age and sex. Research on social and biological factors underlying the lethality of SA is crucial for a better understanding of this complex phenomenon. Identifying potential predictors of SA, especially those at high lethality, is essential to implement personalized preventive strategies.

Hyper/neuroinflammation in COVID-19 and suicide etiopathogenesis: Hypothesis for a nefarious collision?

Accumulating scientific and clinical evidence highlighted pathological hyperinflammation as a cardinal feature of SARS-CoV-2 infection and acute COVID-19 disease. With the emergence of long COVID-19 syndrome, several chronic health consequences, including neuropsychiatric sequelae, have gained attention from the public and medical communities. Since inflammatory mediators have also been accredited as putative biomarkers of suicidal ideations and behaviors, hyper- and neuroinflammation might share some colliding points, overlapping and being interconnected in the context of COVID-19. This review aims to provide a summary of current knowledge on the molecular and cellular mechanisms of COVID-19-associated hyper/neuroinflammation with focus on their relevance to the inflammatory hypothesis of suicide development. Subsequently, strategies to alleviate COVID-19 hyper/neuroinflammation by immunomodulatory agents (many of which at experimental stages) as well as psychopharmacologic/psychotherapeutic approaches are also mentioned. While suicide risk in COVID-19 survivors - until now little known - needs further analysis through longitudinal studies, current observations and mechanistic postulates warrant additional attention to this possibly emerging mental health concern.

Peripheral BDNF levels in psychiatric patients with and without a history of suicide attempt: A systematic review and meta-analysis

OBJECTIVE

Psychiatric patients are at increased risk of attempting suicide. Several potential biomarkers of suicide risk have been proposed with inconsistent findings. The present paper aimed to evaluate differences in peripheral BDNF levels between psychiatric patients with and without a history of suicide attempts.

METHODS

We conducted a systematic review and meta-analysis following the PRISMA guidelines. Relevant papers published up to January 5, 2021 were identified searching the electronic databases Web of Knowledge^SM and PsycINFO. A random-effect meta-analysis was conducted using Stata 16.

RESULTS

Thirteen studies met inclusion criteria. Overall, no significant differences in BDNF levels between the two groups were found (13 studies, n = 1340, Hedge's g = -0.21, 95% CI -0.44 to 0.02). Heterogeneity was substantial (I² = 72.91%). Subgroup analyses revealed that BDNF levels were significantly reduced in plasma with medium effect size (5 studies, n = 363, Hedge's g = -0.44, 95% CI -0.86 to -0.02), but not in serum (8 studies, n = 977, Hedge's g = -0.09, 95% CI -0.33 to 0.15). No significant differences were found according to the type of diagnosis (major depressive disorder vs. other diagnoses) or the period of suicide attempt (lifetime vs. recent).

CONCLUSION

The utility of BDNF as a biomarker of suicide attempts in psychiatric patients appears limited to its plasma concentration. Although caution interpretation is needed, our findings may represent a starting point for the design of rigorous case-control studies exploring the association between neurotrophins and suicidal behaviors.

The impact of the COVID-19 pandemic on suicide ideation and suicide attempts in a sample of psychiatric inpatients

There has been little research reported regarding both suicide ideation and suicide attempts during the COVID-19 pandemic and government lockdown restrictions in Italy, one of the countries most affected by the pandemic. We investigated whether the frequency of suicide ideation and suicide attempts differed between psychiatric patients admitted to a psychiatric unit before and during the COVID-19 pandemic and government lockdown restrictions. We also assessed psychiatric diagnosis, length of hospitalization, and types of admission. We collected data on 632 psychiatric patients admitted to a public psychiatric clinic. Patients were divided into two different groups according to their admission before or during the COVID-19 pandemic. Our results showed that only suicide attempts, but not suicide ideation, were more frequent in psychiatric patients admitted during the COVID-19 pandemic than before. Furthermore, mood disorder diagnoses were more frequent during the COVID-19 pandemic than before the pandemic. The types of admission and the mean length of hospitalization did not differ between the two groups. In conclusion the present study results adds consistent knowledge on the phenomenon of suicide during the challenging time of the pandemic, pointing to continuing effort in suicide prevention measures.

Sunshine, temperature and suicidal behaviour in patients treated with antidepressants: an explorative nested case-control study

Our aim was to explore if different exposure windows for sunshine or temperature are associated with increased suicidal behaviour among people starting antidepressant treatment. 307 completed and 1674 attempted suicides were included as cases in the conditional logistic regression analyses, while controlling for potential confounders, including season, as well as temperature and hours of sunshine when these variables were not the main exposure variable. Ten controls were matched to each case using risk-set sampling. The role of season, age, and sex was examined with likelihood ratio tests (LRTs) with and without the respective interaction terms and with stratified analyses. There was no overall association between temperature or sunshine with suicidal behaviour. Age was a significant effect modifier for suicide and suicide attempt for both sunshine and temperature exposure. In stratified analyses, an increase of one degree Celsius in the average daily temperature during the last 4 weeks was associated, in the unadjusted model, with a 3% increase in the rate of suicide (p = 0.023) amongst older patients (65+). In the same age group, an increase of 1 h in the average daily sunshine during the last 4 weeks was associated with an 8% increase in the rate of suicide attempt (p = 0.002), while the respective increase for the exposure period of 5–8 weeks was 7% (p = 0.007). An increase of one degree Celsius in the average daily temperature during the last 4 weeks was associated with a 3% increase in the rate of suicide attempt (p = 0.007). These associations did not retain statistical significance in the adjusted models. No associations were found in the other age groups. Our results point to a possible effect modification by age, with higher risk of suicidal behavior associated with an increase in sunshine and temperature found in the older age groups.

Pattern of Suicide Methods and Postmortem Toxicological Findings in Suicide-Related Deaths: A Retrospective 7-Year Forensic-Based Study in Iran

ABSTRACT

Suicide is a public health threat that leads to morbidity and mortality worldwide. In this study, we evaluated postmortem toxicological finding among forensic autopsies on suicidal deaths from 2010 to 2016 at the Legal Medicine Center of Zanjan Province (northwest of Iran). All suicide fatal cases were investigated to define the cause and manner of death. Toxicological analyses were performed using thin-layer chromatography, high-performance liquid chromatography, gas chromatography/mass spectrometry, headspace gas chromatography, and gas chromatography equipped with nitrogen phosphorus detector. Demographic data (age, sex, educational level, residential location, and marital status), cause of death, and postmortem toxicological findings were extracted from forensic reports and were entered into the designed questioners. During this period, a total of 181 cases of suicide deaths were investigated. Among them, 74% were male. The most often used suicide method was hanging, followed by self-poisoning in young people. Aluminum phosphide was the most frequent poison detected in the fatal suicidal cases (33 cases), followed by opioids. Hanging and self-poisoning were the frequent suicidal method in young male population. It seems that psychological and social supports in young people along with restriction to easy access to drugs and poisons should be considered by policy making and healthcare authorities.

The Need for Collective Awareness of Attempted Suicide Rates in a Warming Climate

Background: Climate factors may offer a stronger explanation of the variations in suicide rates compared with economic variables, even in the case of patients admitted involuntarily. Aims: We assessed the role of temperature as a determinant of the increased prevalence of suicide attempts (SA). Method: The sample comprised all cases of hospitalization for SA at the Psychiatric Clinic of the IRCCS Ospedale Policlinico San Martino between August 2013 and July 2018. For ambient temperature, data were provided by the Meteorological Observatory of the University of Genoa. Results: We noted a peak in suicides that was typically found in late spring and early summer due to global warming. Limitations: Other environmental/psychological factors contributing to the onset of an acute clinical event were not considered. The cross-sectional design of the study is another limitation. Conclusion: Further studies are needed to clarify the impact of climatic factors on suicide behavior and implement early intervention and preventive strategies for mental health.

High-lethality of suicide attempts associated with platelet to lymphocyte ratio and mean platelet volume in psychiatric inpatient setting

OBJECTIVES

A wide range of potential psychosocial, biological, genetic and environmental factors may interact with each other in determining suicidal behaviours. The aim of this study was to evaluate several biological parameters referred to the complete blood count values in 259 suicide attempters (SA) and 164 non-suicide attempters (control group), according to the lethality of suicidal behaviour.

METHODS

After attempting suicide, subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the section of Psychiatry from 1 January 2014 to 31 June 2019. Socio-demographic and clinical characteristics, as well as blood cells, were collected.

RESULTS

Individuals with high-lethality suicide attempts had a higher number of neutrophils, mean platelet volume, neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and lower number of lymphocytes relative to both those with low-lethality suicide attempts and control group. After regression analysis, only the mean platelet volume and platelet to lymphocyte ratio resulted associated with a high-lethality suicide attempt (HLSA).

CONCLUSIONS

Our findings provide potential and useful peripheral biological markers able to help clinicians in understanding the complex phenomenon of suicide. However, further studies are needed to confirm the present findings.

Clinical correlates of seasonality in bipolar disorder: A specifier that needs specification?

OBJECTIVE

Seasonal pattern (SP) is a bipolar disorder (BD) specifier that indicates a tendency towards affective relapses during specific moments of the year. SP affects 15%-25% of BD patients. In the past, SP was applied only to depressive relapses while, in DSM-5, SP may be applied to both depressive and (hypo)manic episodes. We examined the association between different clinical correlates of BD and SP according to its current definition in a cohort of patients with BD type I (BDI) and II (BDII).

METHODS

Patients were recruited from a specialized unit and assessed according to the season of relapse and type of episode per season. SP and non-SP patients were compared looking into sociodemographic and clinical correlates. Significant variables at univariate comparisons were included in multivariate logistic regression with SP as the dependent variable.

RESULTS

708 patients were enrolled (503 BDI, 205 BDII), and 117 (16.5%) fulfilled DSM-5 criteria for SP. The mean age was 45.3 years (SD = 14.18), and 389 were female (54.9%). The logistic regression model included a significant contribution of BDII (OR = 2.23, CI 1.4-3.55), family history of mood disorder (OR = 1.97, CI 1.29-3.01), undetermined predominant polarity (OR = 0.44, CI 0.28-0.70), and aggressive behavior (OR = 0.42, CI 0.23-0.75).

CONCLUSION

Our results outline a novel positive association of SP with undetermined predominant polarity, BDII, family history of mood disorder, and with fewer aggressiveness-related symptoms. Seasonality is associated with a biphasic pattern with similar dominance of (hypo)mania and depression and is more frequent in BDII as compared to BDI. Seasonal episodes may be easier to predict, but difficult to prevent.

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.

Suicide and apparent temperature in the two capitals cities in the iberian peninsula

Different authors have identified geographic variations in the rates of suicide. This study aims to discuss the limitations of the officially recorded suicide data and to evaluate the statistical relationship between a biometeorological index, Apparent Temperature (AT), and suicide in Madrid and Lisbon. We performed a time-series study. The association was analyzed using a quasi-Poisson regression model. To assess potential delayed and non-linear effects of AT on suicides, a lag non-linear model was fitted in a generalized additive model. There was an average rate of 3.30 suicides/100,000 inhabitants in Madrid and of 7.92 suicides/100,000 inhabitants in Lisbon, and a downward trend was found throughout the period. In Madrid, there is no statistically significant association between AT and suicide. However, in Lisbon, under higher AT, there was a higher risk of suicide. The highest accumulated statistically significant Relative Risk (RR) of suicide was detected at 7 days after the exposure, when at 38 °C, the risk of suicide is 2.7 times that existing at the median AT, 20.62°. The average mortality rate recorded in Lisbon was 41.6% higher than that registered in Madrid. However, the limitations of suicide record databases in Spain and Portugal have to be taken into account when analyzing incidence and especially when comparing data from different countries. It is necessary to improve the filing systems of violent deaths in order to perform reliable epidemiological studies.

The effect of meteorological variables on suicide

We aimed to reveal the relationship between the meteorological variables and suicide rates (completed suicides and suicide attempts) independently of the seasonal cycle and holiday effects. This is an observational retrospective study. We collected the data on age, gender, and suicide method of all suicide cases transferred to hospitals from the scene by emergency medical services as well as those cases in which the victim died on the scene between January 1, 2017 and June 30, 2019. We also collected data on maximum, minimum, and average temperatures (°C), average humidity (%), and average actual pressure (hPa) measured daily in Ankara. The total number of cases due to suicide between the given dates was 6777. The suicide method in 60.1% of the cases was drug poisoning, which was the most common suicide method. Investigating the effect of meteorological variables on suicide cases (suicide attempts and completed suicides), the present study found that after smoothing the effect of the day of the week and seasonality, an increase in the minimum temperature on the day of the application by 1 unit (1°C degree) leads to an increase in the number of suicides by 0.01 point (0.01 ± 0.005, p = 0.046). There was no significant change in the variables other than the minimum temperature. We believe that the results of the present study will contribute to growing body literature about the epidemiology of suicide. We also believe that there is a need for large-scale studies that include individual data to reveal causality.

Short-term effect of apparent temperature on daily emergency visits for mental and behavioral disorders in Beijing, China: A time-series study

BACKGROUND

The relationship between temperature and mental disorders is still unclear. This study aims to assess the short-term effect of apparent temperature (AT) on daily emergency visits of mental and behavioral disorders (MDs) in Beijing, China.

METHODS

Daily counts of emergency visits related to MDs in Beijing from 2016 to 2018 were obtained. A quasi-Poisson generalized additive model combined with a distributed lag non-linear model (DLNM) was applied to analyze the lag-exposure-response relationship between AT and emergency admissions related to MDs. Sunshine duration, precipitation, PM_2.5, SO₂, O₃, time trend, day of week and holiday were adjusted in the model.

RESULTS

Total daily emergency visits for MDs during the study period were 16,606. With the reference of -2.4 °C (temperature with the minimum emergency visit risk), the single day effects of low AT (-8.6 °C, 10th percentile) and high AT (9.2 °C, 90th percentile) on MDs emergency visits reached a relative risk peak of 1.043 (95%CI: 1.017-1.069) on lag day 4 and 1.105 (95%CI: 1.006-1.215) on lag day 1, respectively. The greatest cumulative effect of high AT emerged on lag 0-5 days and reached a relative risk of 1.435 (95%CI: 1.048-1.965), while no significant cumulative effect of low AT was observed. There was a significant effect of high AT on emergency visits of MDs due to psychoactive substance use and male patients.

CONCLUSIONS

Both low and high AT are demonstrated to be the significant risk factors of MDs, which highlights the need of strengthening the health interventions, patient medical services and early warning for patients.

Predictors of relapse in high lethality suicide attempters: a six-month prospective study

BACKGROUND

This study is aimed to investigate the association between clinical, metabolic, inflammatory and environmental (photoperiod defined as daily sunlight exposure) parameters and suicide re-attempts after the index suicide attempt. Possible predictors of suicide re-attempts were also explored.

METHODS

Overall, 432 subjects with suicide attempts, of which 79 relapsed within the following six months were included in this prospective study. We adopted the Joiner's definition of suicide lethality, as "the acquired ability to enact lethal self-injury". The Cox regression was used to test the association between the mentioned variables and Kaplan-Meier plots showed the trend of suicide re-attempts.

RESULTS

Among participants, 30.8% committed a high-lethality suicide attempt. Cox regression confirmed the association between lifetime suicide attempts and number of suicide attempts in the study time-frame and suicide-reattempts. The longer photoperiod (Spring/Summer) was associated with suicide re-attempts, particularly patients with admission in June/July for the index event. Total cholesterol (TC), low-density lipo-protein cholesterol and c-reactive protein serum levels were significantly associated with suicide re-attempts but Cox regression confirmed only the association between lower TC serum levels and suicide re-attempt.

LIMITATIONS

Patients' seasonal environment, psychological factors, presence of acute life-events fostering the suicidal crisis and detailed medical history have been not investigated. Findings were derived from a single psychiatric unit.

CONCLUSIONS

Lifetime suicide attempts, higher number of previous suicide attempts, lower total cholesterol levels, and suicide attempt during longer photoperiod were significant predictors of suicide re-attempts. Further studies are needed in order to better characterize single- vs. multiple suicide attempter's profiles.

Risk Factors for Serious Suicide Attempts: Difference Between Older and Younger Attempters in the Emergency Department

Objective: Suicide attempts of the older adults are known to be more serious than that of the younger adults. Despite its major social impact in South Korea, the behavioral mechanism of serious suicide attempt (SSA) in old people remains to be elucidated. Thus, we investigated the risk factors for SSA in older and younger suicide attempters in the emergency department. Methods: Demographic data, clinical information, and the level of seriousness of suicide with Risk Rescue Rating Scale were compared between older (age ≥65) and younger (age <65) adults who visited the emergency department for a suicide attempt. Regression analyses were performed to identify the risk factors for SSA in these two groups. Results: Among 370 patients, 37 were older adults (10%; aged 74.41 ± 6.78), more likely to have another medical disease (p < 0.001), and a higher suicide completion rate (16.2 vs. 5.4%, p = 0.023). In the younger group, old age (B = 0.090, p < 0.001), male sex (B = -0.038, p = 0.019), and impression of schizophrenia (B = 0.074, p = 0.027) were associated with a higher risk-rescue ratio and interpersonal stress condition was associated with a lower risk-rescue ratio (B = -0.045, p = 0.006). In the older group, however, no variables were included significant in the regression model for the Risk Rescue Rating Scale. Conclusions: Demographic and clinical factors such as old age, male sex, interpersonal stress, and impression of schizophrenia were associated with lethality in the younger suicide attempters. However, no factors were associated with SSA in the older adult group. Different mechanisms may underly the lethality in old age suicide.