Age and sex subgroups vulnerable to copycat suicide: evaluation of nationwide data in South Korea

Abstract

Media reports of a celebrity's suicide may be followed by copycat suicides, and the impact may vary in different age and sex subgroups. We proposed a quantitative framework to assess the vulnerability of age and sex subgroups to copycat suicide and used this method to investigate copycat suicides in relation to the suicides of 10 celebrities in South Korea from 1993 to 2013. By applying a detrending model to control for annual and seasonal fluctuations, we estimated the expected number of suicides within a copycat suicide period. The copycat effect was assessed in two ways: the magnitude of copycat suicide by dividing the observed by the expected number of suicides, and the mortality rate by subtracting the expected from the observed number of suicides. Females aged 20-29 years were the most vulnerable subgroup according to both the magnitude of the copycat effect (2.31-fold increase over baseline) and the mortality rate from copycat suicide (22.7-increase). Males aged 50-59 years were the second most vulnerable subgroup according to the copycat suicide mortality rate (20.5- increase). We hope that the proposed quantitative framework will be used to identify vulnerable subgroups to copycat effect, thereby helping devise strategies for prevention.

Figure 1

Magnitude of copycat suicides in female (upper two rows) and male (bottom two rows) age subgroups following Celebrity 1’s suicide. The expected number of suicides was estimated by detrending linear regression models (solid lines). The observed numbers of suicides during the copycat period of all years except 2008 are shown by circles. The observed numbers of suicides during the copycat suicide period of 2008 are shown by triangles. The ratios of the observed to the expected numbers of suicides are shown as numbers above (or below) the triangles.

Figure 2

The magnitude of copycat suicide and the mortality rate from copycat suicide according to age and sex subgroups. (a) Copycat effect magnitude and (b) copycat suicide mortality rate and 95% confidence intervals according to age (total, 10–19, 20–29, 30–39, 40–49, 50–59, 60–69 years) and sex (females, circles and solid lines; males, triangles and dashed lines) for the total of 10 celebrity suicide cases (C1–C10).

Figure 3

Relationship between the sex of the suicided celebrity and the sex of the person who committed copycat suicide. (a) Copycat effect magnitude and (b) copycat suicide mortality rate and 95% confidence intervals according to age (total, 10–19, 20–29, 30–39, 40–49, 50–59, 60–69 years) and sex (females, circles and solid lines; males, triangles and dashed lines) for female (C1–C5) and male (C6–C10) celebrity suicide cases (c,d).

Figure 4

Relationships between the age of the celebrities and the age of person who committed copycat suicide. (a) Copycat effect magnitude and (b) copycat suicide mortality rate and 95% confidence intervals for victims of similar age group (from 5 years younger to 5 years older than the celebrity; circles and solid lines) and dissimilar age group (triangles and dashed lines) for each of the celebrity cases (C1–C10).