Season of birth in suicides: excess of births during the summer among schizophrenic suicide victims

Suicide means, timing, intent and behavior characteristics of the suicides with schizophrenia

BACKGROUND

Studies have been reported on suicide and schizophrenic suicide, but few compared certain characteristics of suicides with and without schizophrenia.

METHODS

A sample of 392 suicides was consecutively recruited from 16 counties in three provinces of China. Psychological autopsy method was applied to collect the information through informants. The questionnaire of characteristics for suicidal behavior, Beck's Suicide Intent Scale (SIS), and the DSM-IV based SCID were applied.

RESULTS

About 9.7% of the sampled suicides (n = 38) were diagnosed with schizophrenia, and they were more likely to be female and older in age. No significant differences were found on violent suicide means, but significant differences within non-violent means between two groups. Schizophrenic suicide was more likely to happen in the second quarter of the year (April - June), middle of the month (11th-20th), and in the afternoon (3:01 pm - 6:00 pm). The schizophrenic suicides had higher suicide intent than those without schizophrenia and were more inclined to be isolated, more likely to tell people their suicide intent, and less likely to prepare posthumous papers.

CONCLUSION

Schizophrenic suicides have unique characteristics, and targeted preventive measures should be taken to prevent schizophrenic suicides. To accurately identify characteristics of suicide behavior is meaningful to prevent schizophrenic suicides in clinical practice.

Characteristics and Risk Factors for Suicide in People with Schizophrenia in Comparison to Those without Schizophrenia

BACKGROUND

Little research has been conducted that compares suicide cases with and without schizophrenia. The aim of the present study was to identify demographic, personal, social, relational, and psychological characteristics among suicides identified posthumously with schizophrenia compared to those without.

METHODS

The DSM-IV was used to independently assess the presence of schizophrenia among suicide cases by two psychiatrists. Data on risk factors was collected through a psychological autopsy method, which included structured interviews of two informants for each suicide case (a family member and a close friend). Interview questions included demographic characteristics, suicide risk factors, the Beck Hopelessness Scale, Dickman's Impulsivity Inventory, the Spielberger State-Trait Anxiety Inventory, the Hamilton Depression Scale and the Duke Social Support Inventory.

RESULTS

The prevalence of schizophrenia was 9.69% among suicide cases in this sample. The schizophrenia suicide group was more likely to be female, older, in poorer physical health, suffer from chronic disease, suffer other psychological disorders, and have a family history of psychological disorders compared to those not diagnosed schizophrenia. Other important risk factors included more frequent past suicide attempts, increased levels of depression and anxiety, lower levels of impulsivity, lower help seeking from friends, and lower social interaction social support.

CONCLUSIONS

There is a notable link between schizophrenia and suicide in China. Identification of social, personal, relational, and psychological risk factors could beneficially guide attempts to improve future preventive measures against suicide among those with schizophrenia in China.

[Time-related aspects of suicides - suicide frequency related to birthday, major holidays, day of the week, season, month of birth and zodiac signs]

BACKGROUND

Suicides are generally the consequence of overchallenged coping strategies of individual for psychological, social or internal and external biological strain factors. Timing of the suicide, too, may be influenced by external factors. Studies so far have yielded in part inconsistent results concerning the association of suicides with particular days or periods of the year. Even less is known regarding a potential effect of the time of birth on suicide risk.

METHODS

The Tyrol Suicide Register (TSR) provides data on suicides occurring in the Austrian State of Tyrol including birthday of the suicide victim and day of the suicide. In the present study the frequency of suicides was analyzed with regard to birthday, day of the week, major holidays and season over a period of 17 years. Further, a potential association with month of birth and zodiac signs was studied.

RESULTS

We found a significant variation in suicide frequency concerning day of the week with a peak on Mondays and Tuesdays and seasonality with increased numbers in spring and summer months.

CONCLUSIONS

The increase of suicide numbers at the beginning of the week may be explained by the "broken-promise effect" which has been described as the consequence of frustrated expectations concerning the weekend. Possible explanations for the suicide peaks in spring and summer may be biological, specifically serotonergic alterations as well as the experience of depressed patients perceiving the social and emotional contrast to people who are able to enjoy these periods of pleasure and outdoor activities.

Season of birth is different in Inuit suicide victims born into Traditional than into Modern Lifestyle: a register study from Greenland

BACKGROUND

There is growing evidence that living conditions at birth play a role in medical conditions later in life. Population-based studies from the Northern Hemisphere have shown that persons born in the spring or summer are at greater risk of committing suicide. A statistical correlation with light availability at birth has been observed in past research, but the cause remains unknown. Greenland is one of the most extreme of natural human habitats with regard to seasonal changes in light. The combination of rapid social changes and reliable population statistics offers a unique opportunity to make comparisons between persons born into a Traditional Lifestyle and those born into a Modern Lifestyle. The aim of this work was to assess whether season of birth differed between suicide victims born into an old or into a modern lifestyle.

METHODS

Official population and mortality registers were used. Suicide victims born (1903-1950) into the Traditional Lifestyle were compared with those born into the Modern Lifestyle (1961-1980). Rayleigh's test for circular distributions was used to assess the season of birth in suicide victims. Data regarding season of birth in the general population were collected.

RESULTS

Persons born in March-June in the Traditional Lifestyle were much less likely to commit suicide than those born during other periods of the year. This is contrary to the findings of other studies. The seasonal differences had disappeared for those born into the Modern Lifestyle. The suicide rate increased from very low rates to about 140 suicides/100 000 person-years in the 1980s.

CONCLUSIONS

The reason behind a variation in season of birth in suicide victims born into the old lifestyle is unknown. It is also unknown why the seasonal difference had disappeared with modern lifestyle. Possible influence of artificial light, nutrition, microbiota and seasonal infections are discussed. The underlying causes behind suicides may be different in traditional and modern Greenland.