Background: The majority of suicides had never had contact with the mental health care system. The aim of this study is to investigate the specific characteristics of this particular group.
Methods: Coroners' files were examined for all 256 suicide victims in the Canton of Lucerne between 2002 and 2006, together with the data from the files of the public psychiatric institutions for individuals who had been registered as patients. The sociodemographic, suicidological and clinical variables of suicides who had been psychiatric patients were compared with those of other suicides. Within the latter group, suicides with remarks on their mental state in the coroner's files ("police diagnosis") were compared with suicides without such remarks.
Results: Assisted suicides (24/256 [9.4%]) were excluded from the comparative analysis. 151 (65.1%) of the remaining 232 suicides had never been registered by a public psychiatric service; 40 (26.5%) of these had a "police diagnosis". In the regression analysis intoxication as a suicide method, announcement of suicide and impaired health characterised suicides with an established psychiatric diagnosis, whereas suicides without a psychiatric diagnosis were more likely to be retired. Among the latter, those without a "police diagnosis" were more likely to have left a suicide note.
Conclusions: Unexpectedly, the only difference between suicide methods with and without former contact with the mental health system was poisoning. Within the latter group, the subgroup without "police diagnosis" left more suicide notes. Further qualitative analyses of suicide notes might be useful in improving understanding of the motives of suicides without a manifest psychiatric history.