Filicide in offspring of parents with severe psychiatric disorders: a population-based cohort study of child homicide.

OBJECTIVE Although rare in absolute terms, risk of homicide is markedly elevated among children of parents with mental disorders. Our aims were to examine risk of child homicide if 1 or both parents had a psychiatric history, to compare effects by parental sex and diagnostic group, and to assess likelihood of child homicide being perpetrated by parents according to their psychiatric history. METHOD A prospective, register-based cohort study using the entire Danish population born between January 1, 1973, and January 1, 2007, was conducted. Follow-up of the cohort members began on their date of birth and ended on January 1, 2007; their 18th birthday; their date of death; or their date of emigration, whichever came first. We used the Danish national registers from 1973 to 2007 to study homicide risk between children whose parents were previously admitted to a psychiatric hospital, including diagnosis-specific analyses, versus their unexposed counterparts. In addition, we used police records during 2000 to 2005 to examine whether or not 1 of the parents was the perpetrator. Rates of homicide were analyzed using survival analysis. RESULTS Children of parents previously admitted to a psychiatric hospital had an overall higher risk of being homicide victims (MRR = 8.94; 95% CI, 6.56-12.18). The risk differed according to parental sex and psychiatric diagnosis (ICD-8 and ICD-10 criteria). The absolute risk of homicide was 0.009% if neither parent had been admitted before the birth of their child and 0.051% if 1 of the parents had previously been admitted. During 2000 to 2005, 88% of the child homicide cases were filicide victims. This percentage was not significantly different for parents with a previous psychiatric admission versus those without such a history. CONCLUSIONS In the large majority of Danish child-homicide cases, a parent was the perpetrator, regardless of whether there had been parental admission to a psychiatric hospital. Children of parents previously admitted had a higher risk of being homicide victims, and risks were especially high in young children whose mothers were hospitalized with affective disorders or schizophrenia. However, the relative risks presented in the current study are based on extremely rare events, and the overwhelming majority of children whose parents have a psychiatric history do not become homicide victims.