Suicide in psychiatric patients : case-control study in Singapore

Objective: Persons with psychiatric illness, especially depression and schizophrenia, are at relatively high risk of suicide, but there are few studies that look at the Asian population. The aim of the present study was to identify the risk period and risk factors for suicide in psychiatric patients in Singapore. The nature of psychiatric care that was provided, both inpatient and outpatient, was also explored. Method: This is a case-control study of 123 patients who committed suicide from 2003 to 2004. Controls were 123 surviving patients who were individually matched for age, gender, principal diagnosis and calendar time. Results: The most common principal diagnoses among the suicide subjects were schizophrenia (46.3%) and depression (26.8%). Numerous factors were associated with significantly increased suicide risk. Stepwise conditional logistic regression showed that the following three independent factors best predicted suicide: history of attempted suicide using highly lethal means; coexisting significant physical illness; and delusions. Suicides occur mainly soon after discharge and after an outpatient consult. Subgroup analyses were done to distinguish between subjects who suicided early and late following discharge. Conclusions: Suicidal risk remains high in Singaporean psychiatric patients soon after discharge. They share some common risk factors for suicide identified in Western studies but the lower prevalence of substance abuse and comorbidity in Singaporean suicide subjects was one notable difference. The phenomena of suicides soon after discharge and outpatient review suggest the need for proper identification and more intensive follow up during this period.