Seasonal variation in suicides re-examined: no sex difference in Hong Kong and Taiwan

Springtime Peaks and Christmas Troughs: A National Longitudinal Population-Based Study into Suicide Incidence Time Trends in the Netherlands

BACKGROUND

Time trends are one of the most studied phenomena in suicide research; however, evidence for time trends in the Dutch population remains understudied. Insight into time trends can contribute to the development of effective suicide prevention strategies.

METHODS

Time trends in national daily and monthly data of 33,224 suicide events that occurred in the Netherlands from 1995 to 2015 were examined, as well as the influence of age, gender, and province, in a longitudinal population-based design with Poisson regression analyses and Bayesian change point analyses.

RESULTS

Suicide incidence among Dutch residents increased from 2007 until 2015 by 38%. Suicide rates peak in spring, up to 8% higher than in summer (p < 0.001). Suicide incidence was 42% lower at Christmas, compared to the December-average (IRR = 0.580, p < 0.001). After Christmas, a substantial increase occurred on January 1, which remained high during the first weeks of the new year. Suicide occurred more than twice as often in men than in women. For both genders, the results indicated a spring time peak in suicide incidence and a trough at Christmas. Suicide rates were highest in the elderly (age group, 80+), and no evidence was found of a differential effect by season in the age groups with regard to suicide incidence. No interaction effect was found with regard to province of residence for both season and Christmas, indicating that no evidence was found that these time trends had differential effects in the Dutch provinces in terms of suicide incidence.

CONCLUSION

Evidence was found for time trends in suicide incidence in the Netherlands. It is recommended to plan (mental) health care services to be available especially at high-risk moments, at spring time, and in the beginning of January. Further research is needed to explore the protective effect of Christmas in suicide incidence.

The effectiveness of suicide prevention programmes: urban and gender disparity in age-specific suicide rates in a Taiwanese population

OBJECTIVE

The effectiveness of suicide prevention programmes is an important issue worldwide today. The impact of urbanization and gender is controversial in suicide rates. Hence, this study adjusted on potential risk factors and secular changes for suicide rates in gender and rural/urban areas.

STUDY DESIGN

Observational study.

METHODS

A Suicide Prevention Center was established by the Executive Yuan in Taiwan in 2005 and tried to carry out suicidal intervention in the community in every city and town. There were two phases, including the first phase of the programme from 2005 to 2008, and the second phase of the programme from 2009 to 2013. The crude suicide rates data from the period of 1991-2013, which recruited nine urban and 14 rural areas in Taiwan, were extracted from the Taiwanese national mortality data file. The suicide rates in two areas of Taiwan (Taipei city and Yilan County) were further used to compare the differences between urban and rural areas.

RESULTS

The results show that unemployment increased the suicide rate in men aged 45-64 years and in women older than 65 years of age in Taiwan. High divorce and unemployment rates resulted in increased suicide rates in men in the city, whereas emotional distress was the main cause of suicides in men in rural areas. The main method of suicide was jumping from a high building for both sexes in the city, whereas drowning was the most common method of suicide for men in rural areas.

CONCLUSION

Following the intervention programme, suicide behaviour began to decrease in all urban and rural areas of Taiwan. This study showed the cumulative effect of the intervention programme in decreasing the suicide rate in Taiwan. Moreover, the gender-specific suicidal rate and disparity in suicidal methods in urban and rural areas should be considered in further preventive strategies in Taiwan.

Diminishing seasonality of self-harm: Temporal trends in Hong Kong SAR

BACKGROUND

The study of temporal variation in self-harm is important to understanding the underlying mechanisms of its occurrence. There are fewer studies on temporal variation in self-harm than in suicide. The aim of this study was to examine the seasonality of self-harm in Hong Kong and to test the hypothesis of diminishing seasonality.

METHODS

We used secondary data from medical records of self-harm obtained from all the public hospitals in Hong Kong under the management of the Hospital Authority. We identified 59,473 distinct episodes involving 36,411 patients. From these, monthly statistics of self-harm from January 2002 to December 2011 were calculated. Harmonic analysis was conducted to examine the presence and magnitude of seasonality.

RESULTS

A bi-seasonal pattern alongside a stronger one-cycle pattern from 2002 to 2006 was identified. During the period 1997-2001, this contracted to a one-cycle pattern with a peak in summer (May to July) and a nadir in winter (December). The magnitude of seasonality diminished greatly, as shown by harmonic analysis. The extent of diminishing seasonality was larger among women and people under 55 years old.

LIMITATIONS

The study covered only self-harm patients who had visited a hospital. Cases which required no medical attention and those where the patient consulted private doctors could not be included, indicating bias towards more severe cases of injury and poisoning.

CONCLUSION

This study provides some evidence of diminishing and even vanishing seasonality of self-harm in Hong Kong, a phenomenon mainly found in younger individuals. It could be related to the increasing use of social media to connect people, especially the younger generation. The impact of seasonal events and activities, as in the past, has become less significant in the social media era.

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.

Impact of economic fluctuations on suicide mortality in Canada (1926-2008): Testing the Durkheim, Ginsberg, and Henry and Short theories

Three theories have been proposed to explain the relationship between suicide and economic fluctuations, including the Durkheim (nonlinear), Ginsberg (procyclical), and Henry and Short (countercyclical) theories. This study tested the effect of economic fluctuations, measured by unemployment rate, on suicide rates in Canada from 1926 to 2008. Autoregressive integrated moving average time-series models were used. The results showed a significant relationship between suicide and economic fluctuation; this association was positive during the contraction period (1926-1950) and negative in the period of economic expansion (1951-1973). Males and females showed differential effects in the period of moderate unemployment (1974-2008). In addition, the suicide rate of mid-adults (45-64) was most impacted by economic fluctuations. Our study tends to support Durkheim's theory and suggests the need for public health responses in times of economic contraction and expansion.

Temporal variations in suicide attempt rates: A hospital-based study from India

Background:

Temporal variations of suicide attempts can help to better understand correlates of suicidal behavior. This study attempted to find the diurnal, weekly, and seasonal variations in suicide attempts at a tertiary care hospital in India.

Materials and Methods:

This record-based study was conducted among patients evaluated at a crisis intervention clinic over a 4-year period at a tertiary care teaching hospital in Southern India. Patients who attempted suicide in recent past and had been medically stabilized were evaluated in this clinic. The distribution of suicide attempts across the time of the day, the day of the week, and month of the year was assessed.

Results:

Of the 407 patients who were included in the analysis, the frequency of suicide attempts varied across time of the day (χ² = 134.504, P < 0.001). The most common period of the day for the attempt was evenings (6 pm to 9 pm). There were no significant temporal associations between month of the year or day of the week and suicide attempts though peaks were observed for June among the months and Sundays among days of the week.

Conclusion:

Diurnal variations exist in the suicide attempts. This has implications on clinical caseloads on emergency departments, especially during the times when staffing might be sub-optimal.

Characteristics of overdose and non-overdose suicide attempts in a multi-ethnic Asian society

BACKGROUND

Overdosing is an accessible method adopted by people attempting suicide in city settings.

AIMS

This study aimed to compare the trends and characteristics of people attempting suicide by drug overdose and by other methods in Singapore.

METHODS

This study examined the medical records of 628 patients who were admitted to a university hospital in Singapore, between January 2004 and December 2006. Patients were classified as overdose and non-overdose persons attempting suicide for comparisons of demographic and suicidal characteristics. Logistic regression was used to determine the odds ratios of various factors associated with self-perceived lethality of the suicide attempt. Patterns of monthly and weekly variations in the frequencies of suicide attempts were also analyzed.

RESULTS

The percentages of Chinese people was higher in the non-overdose group (71.5% vs. 62.9%), while the percentages of Malay and Indian people were higher in the overdose group (31.6% vs. 18.5%). The female gender (OR=0.36, p=0.04) and admission of suicide intention (OR=7.11, p<0.001) were significantly associated with higher perceived lethality of the suicide method in the non-overdose group. Suicide attempts occurred more frequently between May and November, and on Tuesdays.

CONCLUSIONS

Gender and ethnic differences between overdose and non-overdose people attempting suicide were found. Temporal variations of suicidal cases were also noted.

Gender-Based Seasonality of Suicide in Japan, 2005-2012

This study aimed to explore the gender-based seasonal patterns of suicide in Japan between 2005 and 2012. With data from Japanese official reports, we carried out Prais–Winsten regression and Wilcoxon signed-rank test analysis with Stata 12.0 and SPSS 14.0. The suicide number was significantly higher in March, April, May, June, July, and October for both genders. The suicide number in men was markedly higher than that in women in every month. The suicide number in 2010 was lower than that in 2009 for men, while that in 2011 was higher than that in 2010 for women. The findings displayed that the nationwide television and publicity intervention campaigns might have positive effects on decreasing suicide of men while women suffered a post-earthquake increase. In terms of interventions, we should not only square up the seasonal patterns but also the gender differences in vulnerability.

Seasonality of self-destructive behaviour: seasonal variations in demographic and suicidal characteristics in Van, Turkey

OBJECTIVE

Seasonality is one of the most interesting but still elusive issue in suicide research. Linkages of seasonality in suicides to possible contributors such as gender, type of method used, and climatic factors have received attention in different cultures. We aimed at evaluating seasonal trends in suicidal behaviour according to demographic characteristics, reasons for self-destructive behaviour and means preferred in suicide.

METHODS

Our aim was to assess the seasonal variation in self-destructive behaviour in terms of completed and attempted suicides in a 3-year time period from 2008 to 2010 in Van, Turkey. A total of 1448 cases were registered over a 3-year time period in the city. Seasonal deviations in demographic characteristics, reasons for suicide, and methods of suicide were evaluated.

RESULTS

Seasonal distribution of both completed and attempted suicides by gender did not significantly deviate. On the other hand, we found a significant decline in self-destructive behaviours among those who were single and student in the spring. We found a peak in self-destructive behaviours in the autumn among Individuals who suffer from psychological problems.

CONCLUSIONS

Subjects with psychological difficulties were more prone to commit suicide in autumn. Seasonal differences in methods of suicide used by suicidal subjects were not significant.

Weekly lottery sales volume and suicide numbers: a time series analysis on national data from Taiwan

OBJECTIVE

To investigate the association between weekly lottery sales and number of suicide deaths in Taiwan.

METHODS

All suicides aged 15+ years during 2004-2006 in Taiwan were included. Poisson autoregression time series models investigated associations of weekly numbers with contemporaneous and recent sales from two national lotteries in operation. Adjustments were made for seasonal fluctuation, temperature, monthly unemployment and autocorrelation.

RESULTS

In fully adjusted models, suicide deaths were negatively correlated with sales of tickets for a low-prize, low-cost lottery system. However, they were correlated positively with recent sales for a higher-cost, larger-prize system. Both correlations were stronger for male than female suicide numbers but differed in terms of age groups most strongly implicated.

CONCLUSIONS

Associations between lottery sales and suicide numbers differed according to the nature of the lottery. A low-prize, low-publicity system appeared to be more benign than a high-prize, high-publicity one.

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.

Suicide and seasonality

OBJECTIVE

  Seasonal variation of deaths by suicide offers an important pathway in the study of possible suicide determinants of suicide and consequently suicide prevention.

METHOD

  We conducted a review of the literature on suicide seasonality, assessing articles published between 1979 and 2009.

RESULTS

  The majority of the studies confirm a peak in spring, mainly for men, older individuals, and violent methods of suicide. A secondary peak during autumn is observed. There is no common seasonality pattern for suicide methods. However, there are also certain studies that did not confirm seasonal variation. Inconsistent results with reduced, unchanged, and even increased suicide seasonality have been reported. Aspects on the association between seasonality and suicides are discussed. Except sex, age, and method of suicide, other parameters were taken into account to find more specific characteristics of seasonality in suicides as well. The influence of clinical, bioclimatic, sociodemographic as well as biological factors seems to affect the seasonal variation.

CONCLUSION

  Studies from both the Northern and the Southern hemisphere report a seasonal pattern for suicides. These studies are not only an important source of epidemiological data for suicides but also represent a global effort to uncover hidden parameters of this self-destructive behaviour.

Seasonal and socio-demographic predictors of suicide in Ireland: a 22 year study

BACKGROUND

Seasonal influences on suicide have been studied for many years with inconclusive and contradictory findings.

METHODS

Data on suicide in Ireland from 1980 to 2002 was examined to ascertain the contribution of season and demographic variables to suicide. Using Poisson regression modelling and sinusoidal analysis a small seasonal effect (7% from peak to trough) was identified but age, gender, marital status and residence were much larger contributors. The seasonal contribution increased in the latter half of the period under study. There was also a small seasonal effect for method of suicide. The suicide rate was highest in the 40-44 age group after controlling for confounders.

LIMITATIONS

Because this was an ecological study, information on other possible contributors, such as mental illness was not available.

CONCLUSIONS

These findings are discussed in light of international studies. Continuing studies are required to confirm the trend in increasing seasonality in Ireland. Since suicide is highest in those who are middle aged, preventive strategies should be directed to this group.

Seasonality of suicide in Shandong China, 1991-2009: associations with gender, age, area and methods of suicide

BACKGROUNDS

Whether suicide in China has significant seasonal variations is unclear. The aim of this study is to examine the seasonality of suicide in Shandong China and to assess the associations of suicide seasonality with gender, residence, age and methods of suicide.

METHODS

Three types of tests (Chi-square, Edwards' T and Roger's Log method) were used to detect the seasonality of the suicide data extracted from the official mortality data of Shandong Disease Surveillance Point (DSP) system. Peak/low ratios (PLRs) and 95% confidence intervals (CIs) were calculated to indicate the magnitude of seasonality.

RESULTS

A statistically significant seasonality with a single peak in suicide rates in spring and early summer, and a dip in winter was observed, which remained relatively consistent over years. Regardless of gender, suicide seasonality was more pronounced in rural areas, younger age groups and for non-violent methods, in particular, self-poisoning by pesticide.

CONCLUSIONS

There are statistically significant seasonal variations of completed suicide for both men and women in Shandong, China. Differences exist between residence (urban/rural), age groups and suicide methods. Results appear to support a sociological explanation of suicide seasonality.

Re-examination of the seasonality of suicide in Taiwan during 1991-2008: a population-based study

The purpose of the present study was to re-examine the monthly distribution of suicide death rates and the change of the suicide seasonality in Taiwan during 1991-2008. The monthly suicide death rates of the total, male and female populations during January 1991-December 2008 were obtained from a population-based database. There was an upward trend. The means of the monthly suicide rates after adjusting the calendar effect and the upward trend were compared. The suicide data were further analysed in three 6-year periods to explore the change of seasonality. During 1991-2008 in Taiwan, suicide rates had significant peaks in April and May, and nadirs in January and December. The monthly distributions varied during 1991-1996, 1997-2002 and 2003-2008 in the patterns and the statistical significance. There was no linear trend for the change of the seasonality of suicide death rate.

Socioeconomic factors outweigh climate in the regional difference of suicide death rate in Taiwan

The present study explored both socioeconomic and climatic factors to obtain a more comprehensive view of the asymmetric regional suicide death rate during 1998-2006 in Taiwan. The annual suicide death rate, population and meteorological data from 19 cities/counties in Taiwan were analysed by multiple regression. Five socioeconomic (sex ratio, no spouse, aged, unemployment and low income) and three climatic (temperature, rainfall and sunshine) factors were identified as significant, explaining 59.0% of the variance in the total suicide death rate. 'Without spouse' and 'aged' were associated with the highest risk, while 'low income with financial aids' was strongly protective. The most influential climatic factor was 'temperature,' which was negatively correlated with suicide. 'Sunshine' was positively associated with suicide. The socioeconomic and climatic factors contributed 52.7% and 6.8%, respectively, to the variance of the total suicide death rate. Limitations of the study included the fact that no individual events were considered, the study was of relatively short duration and it was confined to the territory of Taiwan. Socioeconomic factors outweighed climatic factors in explaining regional differences in the suicide death rate in Taiwan. Temperature weighed more than sunshine. 'Thermotherapy' seems more clinically relevant than the popular light therapy, at least in Taiwan.

Seasonality in suicide--a review and search of new concepts for explaining the heterogeneous phenomena

Seasonality is one of the oldest and most resistant-to-elucidation issues in suicide research. However, in recent years epidemiological research has yielded new results, which provide new perspectives on the matter. This qualitative review summarizes research published since the 1990 s. In particular, the focus is on studies dealing with the historical change of seasonality, cross-sectional comparisons including method-specific diversity, and the association with weather variables and other putative covariates. Recent research has shown that in Western countries the seasonality of suicide is tending to diminish and may, eventually, disappear. It can no longer be considered a universal and homogeneous phenomenon. In addition, different major seasonal cycles have now been determined which mainly depend on different suicide methods. Just as in the epidemiology of suicide methods, the (seasonal) availability and perceived adequacy of methods emerge as the major driving force beyond the seasonal phenomena in suicide.

Suicide and unemployment rate in Taiwan, a population-based study, 1978-2006

OBJECTIVE

Both the suicide rate and unemployment rate have showed an upward trend in Taiwan since 1994. This study aimed to explore the association between the suicide rate and the unemployment rate. This information is useful in developing specific suicide prevention strategies related to unemployment.

METHODS

All the cases of suicide by those aged 15 years and above during 1978-2006 in Taiwan (n = 74,064) were included in this study. Time series models were used to analyze the monthly age-standardized suicide rate by gender and age-subgroup (15-24, 25-44, 45-64, and 65+).

RESULTS

With regard to the age range and gender subgroup, the association between age-standardized suicide and the unemployment rate was comparatively high for males and those aged from 45 to 64 years. Among males and those aged from 45 to 64 years, a 1% increase in the absolute unemployment rate was associated with a 4.9% (95% confidence interval: 1.7-8.2) increase in the relative age-standardized suicide rate in the monthly average from 1978 to 2006 in Taiwan.

CONCLUSIONS

Suicide prevention strategy for the unemployed should be more focused especially on males aged from 45 to 64 years in Taiwan.

Seasonal Variation of Suicide in Brazil

Most of what is known about the seasonal variation in suicide rate originates from studies conducted in the northern hemisphere; very few studies have been done in the southern hemisphere. The purpose of the present study was to explore the possibility that in Brazil, the seasonal variation of suicides is a function of photoperiod. This was accomplished by analyzing monthly suicide data for a 12 yr period (1979 to 1990), within latitudes ranging from 2 degrees N to 33 degrees S. Single cosinor analyses with periods of 12 or 6 months were applied to time series of monthly total and suicidal deaths, separated by gender and state. Significant spring or early summer peaks of suicide were found only in the south of Brazil for both men and women, except for the latter in one state. These peaks did not coincide with those found for total deaths, which occurred in the autumn or winter in all areas. No significant six-month period was found. In the present study, the chance of a suicide was typically 10-17% higher during the peak period than during the other months of the year. Although this moderate seasonal effect might not be sufficient to justify planning large scale prophylactic interventions, those dealing with patients who have suicide ideation should be aware of this high risk time.

Fań: an idiom of distress among suicidal patients in Taiwan

The purpose of this study is to describe fań, a culturally constructed expression of emotional and psychological discomfort, from the perspective of 34 suicidal patients in Taipei, Taiwan. An important finding from this ethnographic study is an idiom of emotional distress, fań, which is not expressed as related to a body part like in most previous research on expressions of psychological symptoms in Chinese cultures. This description will help health professionals better understand what fań means to Chinese patients and what methods they use to cope with it.

Suicide rates and the association with climate: a population-based study

BACKGROUND

Seasonality of suicide has been noted in several studies. A spring peak of suicide was observed, and associations between various climatic parameters and suicide have been suggested. This study sets out to verify seasonal patterns of suicide rates and to explore the association with climate in Taiwan.

METHOD

The study used a nationwide mortality database in Taiwan from January 1997 to December 2003. An autoregressive integrated moving average model was applied to examine the presence of seasonality and the association of climate with suicidal death.

RESULTS

Seasonality with a spring peak was evident in suicidal death regardless of gender or age. Ambient temperature was positively associated with suicide after adjustment for trend and seasonality.

LIMITATIONS

Misclassification and underreporting of suicidal death in the registry system might confound the results. Ecological fallacies might exist.

CONCLUSIONS

The seasonal effect on suicide is significant in Taiwan. Suicide rates may be influenced by ambient temperatures. The findings are of research interest for future studies regarding mechanisms of suicidal behavior, and also of practical interest for better timing of suicide interventions and effective preventive strategies.

Suicides in the midnight sun--a study of seasonality in suicides in West Greenland

Greenland is the most extreme of human habitats in regard to annual changes in natural light. From being very low, the rate of suicides in Greenland has increased during the past few decades to be among the highest in the world. Several studies have shown seasonality in suicides with spring or summer peaks, but this has not been previously shown in Greenland. Official data from 1968 to 1995 from West Greenland were pooled. A significant seasonality in the 833 suicides was found using Rayleigh's test, a peak in June and a trough in the winter. Suicides increased during the period, and reached high rates in most age groups, up to 577 per 100,000 person-years in men aged 15-24 years in 1990, and up to 147 per 100,000 person-years in women aged 15-24 years in 1995. Violent methods of suicide were used by 93%. Depression has been reported uncommonly. High alcohol intake and extended periods of light in the summer may contribute to impulsive-aggressive summer suicides.

Seasonal fluctuation of suicide in Hungary between 1970-2000

The authors studied the seasonal fluctuation of suicide events in Hungary in a 31-year period. A summer maximum and a winter minimum were found in both genders. A second autumn peak did not occur among women. The suicide rate of Hungary fell markedly in 1998, parallel with the fundamental political-economical-social changes in the country. After 1988 the ANOVA statistic did show a moderate decrease in the seasonal fluctuation but only among those under 29 years of age. This young generation was the real "winner" of the deep social changes which suggests an indirect connection between the decrease of the seasonal fluctuation of suicide and the socio-political changes.

A comparison of seasonal variation between suicide deaths and attempts in Hong Kong SAR

BACKGROUND

Seasonal variations in suicide deaths and attempted suicides have been reported for many countries. Recent research has suggested that seasonal patterns of suicide deaths have diminished considerably. The seasonality pattern between attempts and completed ones are not the same. This paper is the first one to examine seasonal variation between suicide deaths and attempts simultaneously.

METHOD

Census and Statistics Department and the Hospital Authority provided mortality and morbidity data on suicides for the period 1997-2001 in Hong Kong SAR, respectively. Seasonal patterns of suicide deaths and attempts were examined by a harmonic analysis and a non-parametric chi-square test.

RESULTS

A significant seasonal variation was detected in suicide attempts with a markedly bi-seasonal pattern was found amongst females with a peak in May and October; only a cyclic pattern was observed for males with a peak in summer. The female attempters who used non-violent suicide methods contributed to the second peak in October. On the other hand, there was no evidence of significant differences in the seasonal distribution among the suicide deaths for males and females. Only a mild pattern was found amongst females involving in violent suicide deaths, while others can be treated as a random event and no significantly pattern was observed in our study. Overall, a significant difference in seasonal variation existed between suicide deaths and attempts (p-value<0.01).

CONCLUSIONS

This study reinforces the findings that seasonal variation in suicide appears to be diminishing. Also, suicide attempters and completed suicides in Hong Kong seem to arise from two non-identical but overlapping groups in the community.

The cultural context of suicide stigma in Taiwan

In the ethnographic study on which this article is based, the authors investigate experiences after a suicide attempt from the perspective of patients and their family members in Taiwan. Thirty-four patients and 49 family members or colleagues participated in interviews from the point of patients' hospitalization to their return to the community. The postsuicide stigma suffered by patients and their families was based on such cultural themes as Suicide is bu-hsiao (non-filial piety), Suicide results in an inability to transmigrate the soul, and Suicide is inherited. Patients, family members, and colleagues cope with the stigma through explaining suicide as due to "bad luck" or "a kan-huo (hot energy) problem," or by insisting that it was "not a true suicide." These findings suggest that health professionals can move closer to patients and their families and suggest appropriate health care policy through understanding the patient's and the family's explanation of suicide experiences.

Estimation of reporting delay and suicide incidence in Hong Kong

This paper uses a semi-parametric method to examine the reporting delay distribution in suicides in Hong Kong reporting system. The data arise from a rightly truncated situation in which only suicide cases registered before a specific time are known to have occurred; otherwise they are not recorded in the known death files even if they have occurred. It is shown that the poisoning-related suicide deaths have a longer reporting delay than other suicide methods. By modelling the reporting delay function, a Horvitz-Thompson-type estimator is suggested to adjust for reporting delay and to provide a more timely estimate of the suicide incidences for monitoring the suicide problem in Hong Kong. Based on these analyses, we recommended a suitable cut-off date to collect suicide cases occurring in the previous year and reported before this date in Hong Kong.

Adolescent suicide in Hong Kong during 1980-2000

Analyses of adolescent suicide statistics in Hong Kong for the period 1980 to 2000 revealed several phenomena. First, while adolescent suicide rates (10-24 age group) in Hong Kong were relatively stable for the period under study, there was a gradual rising trend where adolescent suicide rates in the 1990s were higher than those in the 1980s. Second, suicide rates for adolescents aged 10-24 were lower than those of other adult age groups. Third, while adolescent suicide rates in Hong Kong were lower than those reported in some English-speaking countries and Mainland China, the figures were higher than those reported in Taiwan. Fourth, suicide rates among teenagers in early adolescence were lower than those among adolescents in late adolescence. Fifth, although male adolescent suicide rates were in general higher than female adolescent suicide rates (10-24 age group), gender differences in suicide rates appeared to be moderated by age. Sixth, there was a gradual rising trend in adolescent proportional mortality rates for suicide in the 1990s. Seventh, proportional mortality rates for suicide among teenagers in early adolescence were lower than those among adolescents in late adolescence. Finally, while jumping from a height was a common method of adolescent suicide, there was a rising trend of using other methods such as taking drugs, hanging and charcoal burning. The observed adolescent suicide phenomena are discussed with reference to the socio-cultural context of Hong Kong.

Use of statistical techniques in studies of suicide seasonality, 1970 to 1997

The effect of seasons on suicides has been suggested repeatedly. In order to reveal a true seasonal pattern, an appropriate statistical technique, which is sensitive to a specific type of cyclic variation in the data, must be chosen. This study is a review of the use of statistical techniques for seasonality and of some important characteristics of study samples that were evaluated from 46 original suicide seasonality articles published in major psychiatric journals. The results showed that statistical techniques were applied in a majority of articles, but they were commonly lacking regarding analyses, which compared seasonal patterns among subgroups of a population. In recent studies more sophisticated statistical techniques were utilized for seasonality, like spectral analyses, as compared with earlier studies, in which the emphasis was on chi-square tests. Lack of reporting essential features of the data, such as the sample size and monthly values of suicides, were frequent. The calendar effect was adjusted only in 11 studies. Some recommendations concerning the methodological and reporting issues are summarized for future articles on the seasonal affect on suicides.

Seasonal variation and meteotropism in suicide: clinical relevance of findings and implications for research

Seasonal asymmetry in yearly suicide occurrence is a long-observed phenomenon in psychiatric, suicidological and sociological research, and the effects of seasonal factors on suicidal behaviour have been the focus of a number of earlier studies. Taking into account limitations of data and methods, these studies have in general favoured interpretations based on psychosocial factors. Recent studies have challenged the widely held notion that seasonal effects on suicide are not influenced by age, gender or the circumstances of the act. The suicides committed with violent methods have been shown to follow clearer seasonal patterns than suicides by less violent methods, and differences have been found between male and female cycles of occurrence. The seasonal occurrence of suicides has also been found to differ significantly between the young and the elderly. The use of inappropriate statistics or age- and gender-biased samples may have hidden a seasonal component in some previous studies on attempted suicide. The absence of seasonality in earlier studies on attempted suicide was interpreted as depending upon the minor relevance of psychiatric and biological factors in non-fatal self-harm. However, recent studies have reported clear seasonality in attempted suicide samples, with older people showing greater seasonal effect. Recent literature after 1985 on seasonal variation and weather or climate influence in attempted and completed suicide is reviewed. Suggestions for research and the development of more effective preventative strategies are offered.

Season and suicide: recent findings from Italy

Seasonal asymmetry in yearly suicide occurrence is a long-observed phenomenon in psychiatric, suicidological, and sociological research, and the effects of seasonal factors on suicidal behavior have been the focus of a number of earlier studies. Taking into account limitations of data and methods, these studies have generally favored interpretations based on psychosocial factors. Recent studies have challenged the widely held notion that seasonal effects on suicide are a unitary phenomenon, not influenced by age, gender, or circumstances of the act. In particular, the seasonal occurrence of suicides has been found to differ significantly between the young and the elderly, and differences have also been found between male and female cycles of occurrence. Suicides using violent methods have been shown to follow clearer seasonal patterns than suicides by less violent methods (such as drug or gas poisoning), possibly reflecting the greater impulsive component involved in the choice of a violent lethal means. In this paper, findings from Italy are used to illustrate the clinical implications of studies into the topic of season and suicide, with the aim of developing more effective preventative strategies.

Seasonal variation in suicides: diminished or vanished. Experience from England and Wales, 1982-1996

BACKGROUND

Seasonal variation in suicidal death has been observed in many countries. In particular, a cyclic variation was found for both men and women in England and Wales in the 1960s and 1970s. Men showed a single 12-month cycle whereas women showed two cycles.

AIMS

To re-examine the seasonal variation in suicides in England and Wales for the period 1982-1996.

METHOD

A harmonic analysis was used to detect the seasonality of the suicide data.

RESULTS

The seasonal effect on suicide is greatly diminished in England and Wales. This is shown by the reduced amplitude and smaller proportion of variance accounted for by the season.

CONCLUSIONS

The seasonal effect on suicide has either diminished or vanished.

Geophysical variables and behavior: LXXXXIX. The influence of weather on suicide in Hong Kong

Summer peaks in suicide for both sexes and ages groups (> or = 55 years) in Hong Kong were ascertained. Barometric pressure had a very weak negative relation with suicide rate.

Occupational sunlight exposure in relation to suicide among electric utility workers

BACKGROUND

Occupational sunlight exposure was examined in relation to death from suicide in a United States cohort of 138,905 male electric utility workers.

METHODS

Case-control sampling included 536 deaths from suicide and 5,348 eligible controls randomly selected from the cohort. Exposure was classified based on work history linked to indices of cumulative sunlight exposure.

RESULTS

Mortality from suicide was not associated with estimates of recent and career occupational sunlight exposure, with adjusted odds ratios around unity. Occupational sunlight exposure was positively associated with nonviolent suicides, but no dose-response gradient was observed and risk estimates were notably imprecise.

CONCLUSIONS

These data provide evidence against an association between occupational sunlight exposure and mortality from suicide.

Urban/rural and gender differentials in suicide rates: east and west

BACKGROUND

Many epidemiological studies indicate suicide rates are higher for males than females and for urban than rural. Here we re-examine gender, urban and rural differentials in suicide in Australia and Beijing (China). More specifically, to test the two hypotheses (i) that the male to female ratio is larger than one; (ii) that the urban suicide rate is higher than the rural in both places.

METHODS

Suicide data with information of gender, rural and urban regions for Australia and Beijing (China) for the period of 1991-1996 were used. Ratios between the gender-specific urban and rural suicides rates with the associated confidence intervals were constructed to examine gender, urban and rural differentials in Australia and Beijing.

RESULTS

The rural suicide rate in Beijing for both genders was higher than for their urban counterparts. Further, the elderly had the highest suicide rate followed by women aged 20-29. Also, the male to female ratio in China was less than one. In Australia, the rural male suicide rate was higher than the urban whereas the urban female suicide rate was higher than the rural. The male to female ratio was 4 to 1. The differences in rural to urban and male to female ratios between Australia and Beijing are statistically significant.

CONCLUSIONS

In contrast to the west, male suicide rates are not higher than female rates in China. Urban rates are not necessarily higher than rural rates --not even in a western setting. Cultural factors and regional differences in socio-economic situation are significant in explaining the low gender ratio and the relatively higher suicide rates in rural China.

LIMITATIONS

The suicide rate in the Beijing region might not exactly reflect the same for the whole of China.

Seasonality in suicides: the influence of suicide method, gender and age on suicide distribution in Italy

In order to ascertain if and how age, gender and choice of lethal means influence the seasonal distribution of suicide in Italy, data concerning all suicides registered in Italy from 1984 to 1995 have been analyzed, taking these variables into account. In the age group 14-65 years and over a total of 31771 male suicides (mean yearly rate, 12.6 per 100000) and 11984 female suicides (mean yearly rate, 4.4 per 100000) have been identified in Italy during the study period. Suicides in the younger age ranges, both among males and females, show a less marked asymmetrical seasonal distribution than those in the older age groups. Only suicides committed by violent methods (ICD 953-958) show clear evidence of seasonality, with a peak in spring and a low in late autumn. Suicides committed by non-violent methods (950-952) follow no seasonal trend in either sex. Spectral analysis reveals a circannual rhythm for violent suicides (ICD 953-958) in both genders. For male non-violent suicides (ICD 950-952), a period with a frequency of 0.0833 (12 months) has been identified, but with a polarity opposite to that of male violent suicides. For female non-violent suicides, no period of frequency of 0.0833 could be identified, but, as for female violent suicides, a period with frequency close to 0.2500 (4 months) has been found. Changes in climate, then, correlate with the monthly distribution of violent and non-violent suicides in opposite ways: male violent suicides show a significant positive relationship with indicators of temperature and exposure to the sun, and a significant negative relationship with indicators of humidity and rainfall. Female suicides show less significant relationships with climate indicators. Work aimed at suicide prevention should therefore take into account the complex influence of seasonal climate both on human biological rhythms (particularly on 5-HT related functions and their actions on mood and impulsivity) and on sociorelational habits.

A re-examination of seasonal variation in suicides in Australia and New Zealand

BACKGROUND

To examine the seasonality of suicides in Australia and New Zealand during the period 1981 to 1993.

METHODS

A chi-square test and a harmonic analysis were used to detect the seasonality of the suicide data.

RESULTS

The reduced amplitude and a smaller proportion of variance accounted for by seasonality suggested the seasonal effect on suicide is greatly diminished. The absence of biseasonal distribution of female suicides was also consistently found in the two countries. The finding was contrary to the reported results in seventies in many Western countries.

CONCLUSIONS

The change in living condition, roles of males and females and communication pattern resulted in the reduction of climatic and environment effect in the seasonality of suicides were suggested.

LIMITATIONS

The results would be better if a longer series of suicide date were available.