Repetition of deliberate self-harm and subsequent suicide risk: long-term follow-up study of 11,583 patients.

BACKGROUND: Repetition of deliberate self-harm (DSH) is a risk factor for suicide. Little information is available on the risk for specific groups of people who deliberately harm themselves repeatedly. AIMS: To investigate the long-term risk of suicide associated with repetition of DSH by gender, age and frequency of repetition.
METHOD: A mortality follow-up study to the year 2000 was conducted on 11 583 people who presented to the general hospital in Oxford between 1978 and 1997. Repetition of DSH was determined from reported episodes prior to the index episode and episodes presenting to the same hospital during the follow-up period. Deaths were identified through national registers.
RESULTS: Thirty-nine per cent of patients repeated the DSH. They were at greater relative risk of suicide than the single-episode DSH group (2.24; 95% CI 1.77-2.84). The relative risk of suicide in the repeated DSH group compared with the single-episode DSH group was greater in females (3.5; 95% CI 1.3-2.4) than males (1.8; 95% CI 2.3-5.3) and was inversely related to age (up to 54 years). Suicide risk increased further with multiple repeat episodes of DSH in females.
CONCLUSIONS: Repetition of DSH is associated with an increased risk of suicide in males and females. Repetition may be a better indicator of risk in females, especially young females.