Background To document rates of mortality from all causes, and rates of further non-fatal suicidal behaviour requiring hospital admission, in the 20 years following a medically serious suicide attempt (MSSA), in a consecutive sample of 302 individuals (mean age 30 years at the time of the index MSSA).

Aims The overall goal of this study is to inform treatment and management options for suicidal patients in order to minimise subsequent risk of fatal and nonfatal suicidal behaviour.

Methods Dates of death, and all sources of mortality, were examined by checks against records contained within the national mortality database. For those who died by suicide and by accidental death, causes of death were confirmed by review of records from coronial inquests. Morbidity data for further suicide attempts requiring hospital admission were obtained by checks of the national hospital admissions database.

Results Within 5  years of a medically serious suicide attempt, 8.9% of the sample had died, 75% by suicide or suspected suicide. Within 10 years, 14.2% had died. By 20 years, one in four was dead.

Significance To our knowledge this is the longest follow up study of people who have made medically serious suicide attempts. Subsequent risks of mortality, and of further non-fatal suicidal behaviour are high and enduring and approach those of some chronic physical illnesses. Long term treatment and management programmes are warranted.