BACKGROUND: Although substance misuse is a key risk factor in suicide, relatively little is known about the relationship between lifetime misuse and misuse at the time of suicide.

AIMS: To examine the relationship between substance misuse and subsequent suicide.

METHOD: Linkage of Northern Ireland’s coroners' reports to primary care records for 403 suicides occurring over 2 years.

RESULTS: With alcohol misuse, 67% of the cohort had previously sought help for alcohol problems and 39% were intoxicated at the time of suicide. Regarding misuse of other substances, 54% of the cohort was tested. Almost one in four (38%) tested positive, defined as an excess of drugs over the prescribed therapeutic dosage and/or detection of illicit substances. Those tested were more likely to be young and have a history of drug misuse.

CONCLUSIONS: A deeper understanding of the relationship between substance misuse and suicide could contribute to prevention initiatives. Furthermore, standardised toxicology screening processes would avoid diminishing the importance of psychosocial factors involved in suicide as a 'cause of death'.