Background. Few controlled studies have investigated factors associated with suicide in current in-patients. We aimed to identify psychosocial, behavioural and clinical risk factors, including variations in care, for in-patient suicide.

Method. We conducted a national population-based case-control study of people who died by suicide between 1 April 1999 and 31 December 2000 while in psychiatric in-patient care in England. Cases were 222 adult mental health in-patients who died by suicide matched on date of death with 222 living controls.

Results. Nearly a quarter of suicides took place within the first week of admission; most of these died on the ward or after absconding. After the first week, however, most suicides occurred away from the ward, the majority of patients having left the ward with staff agreement. Previous deliberate self-harm, recent adverse life events, symptoms of mental illness at last contact with staff and a co-morbid psychiatric disorder were associated with increased risk for suicide. Being off the ward without staff agreement was a particularly strong predictor. Those patients who were detained for compulsory treatment were less likely to die by suicide. Independent predictors of in-patient suicide were male sex, a primary diagnosis of affective disorder and a history of self-harm. Being unemployed or on long-term sick leave appeared to be independently protective.

Conclusion. Prevention of in-patient suicide should emphasize adequate treatment of affective disorder, vigilance in the first week of admission and regular risk assessments during recovery and prior to granting leave. Use of compulsory treatment may reduce risk.