The iceberg of suicide and self-harm in Irish adolescents: a population-based study

Suicide is a leading cause of death among adolescents. Self-harm is the most important risk factor for suicide, yet the majority of self-harm does not come to the attention of health services. The purpose of this study was to establish the relative incidence of adolescent suicide, hospital-treated self-harm and self-harm in the community. Annual suicide rates were calculated for 15-17 year-old in the Cork and Kerry region in Ireland based on data from the Central Statistics Office. Rates of hospital-treated self-harm were collected by the Irish National Registry of Deliberate Self-Harm. Rates of self-harm in the community were assessed using a survey of 3,881 adolescents, the Child and Adolescent Self-harm in Europe study. The annual suicide rate was 10/100,000. Suicide was six times more common among boys than girls. The annual incidence rate of hospital-treated self-harm was approximately 344/100,000, with the female rate almost twice the male rate. The rate of self-harm in the community was 5,551/100,000, and girls were almost four times more likely to report self-harm. For every boy who died by suicide, 16 presented to hospital with self-harm and 146 reported self-harm in the community. For every female suicide, 162 girls presented to hospital with self-harm and 3,296 reported self-harm. Gender differences in relative rates of self-harm and suicide are very large, with boys who have harmed themselves at particularly high risk of suicide. Knowledge of the relative incidence of self-harm and suicide in adolescents can inform prevention programmes and services.