The North Staffordshire Suicide Study: A case-control study of suicide in one health district

Background. The aim of the study was to identify sociodemographic and clinical risk factors for death from suicide and undetermined injury in residents of one health district. Method. Data were collected on all cases of suicide (ICD-9 E950-959) and undetermined injury (ICD-9 E980-989) for residents in North Staffordshire Health District between 1991 and 1995. Controls, identified from the Coroner's inquest register, who died from other causes, were matched for age and sex. Results. Two hundred and twelve pairs of cases and matched controls were identified. Multivariate analysis (conditional logistic regression) showed that the risk of death due to suicide and undetermined death was associated with: recent separation, relationship difficulties, experience of financial difficulties, history of past criminal charges or contact with the police, a past history of deliberate self-harm, being on psychotropic medication at the time of death and a diagnosis of bipolar affective disorder. For sociodemographic variables, a univariate analysis found associations between the cases and being separated, living alone, having a past history of criminal charges and unemployment. Cases were more likely to have a psychiatric disorder, past history of deliberate self-harm and a past history of psychiatric contact for themselves or a family member. Controls were more likely to have a current medical disorder. Cases were more likely than controls to be on any form of medication at the time of death and to have received a prescription for psychotropic or nonpsychotropic medication in the week and month before death. Cases were more likely than controls to have had contact with medical services in the week and month before death, with the general practitioner in the week before death and with psychiatric services at any time in the year before death. Strong associations were found between suicide and undetermined injury and life events such as recent separation and bereavement, and financial and relationship difficulties. Conclusions. The study provides an analytical investigation utilizing a dead control group, data gathered from several sources and adequate numbers of cases. It confirms many of the risk factors identified in other studies and highlights the high proportion of suicides who have been in recent contact with the criminal justice system or have been prescribed medication shortly before death.