The myth of the birthday blues: a population-based study about the association between birthday and suicide

Abstract

Purpose

The problem of time distribution of suicide has aroused the interest of various investigators in the past. A population-based study on the association of the birthday in relation to the time of suicide taking into account sex and the chosen suicide method was conducted.

Methods

The study included all residents of Bavaria who died between 1998 and 2003 and whose death was classified as suicide by the death certificate. In sum, 11 378 deaths from suicide were included. The suicide ratios in various time frames around the individuals' birthdays were compared with expected suicide ratios.

Results

The occurrence of suicide did not vary around the birthday. Different time frames (3, 7, 14, 30, and 90 days) before as well as after the individuals' birthdays were taken into account. Even after dichotomization regarding the chosen method as well as sex differences, no significant association between birthdays and dates of suicide could be found.

Conclusion

There is no evidence for a “birthday blues” effect on suicide.

Introduction

Various factors have been identified as being associated with suicide. Because short- as well as long-term temporal factors greatly influence many daily activities [1], it seems reasonable to assume an influence of such factors on the occurrence of suicide as well. For example, it has been observed that suicide occurred more frequently during the daytime than during the night and therefore presumed that the duration of daylight was a determining factor, for example, in yearly distributions of suicides. The time of death by suicide seems to vary throughout the day [2], [3], [4], [5], [6], [7]. Several investigations studied the timing of deaths through suicide, taking into account specific dates of supposedly significant meaning to the individual, such as his or her own birthday or the birthday of close relatives. Barraclough and Shephard [7] found that suicides committed by elderly people older than 75 years were more likely to kill themselves in a 60-day period around their birthday than chance would predict. In a study on a similar population composed of people older than 75 years, an excess of suicides in the birth month and the following 2 months has been observed [8], whereas others found that death through suicide was significantly more likely to occur within a 3-month period after the individual's birthday than 3 months before [9]. A study on children dying from suicide produced evidence that suicide was more common in a 4-week period around their birthdays [10], although this was discussed controversially in another study, which failed to reproduce such an association [11]. Several reasons for this phenomenon have been addressed in the aforementioned studies. An individual's birthday may affect morale in the elderly, thereby impairing their resistance to fatal disease and giving in to some kind of “birthday stress” [8].

Identifying an association between an anniversary and self-inflicted death may be of practical as well as theoretical value because the defining of high-risk periods of the individual is important for suicide prevention. Therefore, the aim of the present study was to evaluate the association of the individual's birthday and the chosen time for self-inflicted death in a population-based study.