Mortality in Offspring of Parents With Psychotic Disorders: A Critical Review and Meta-Analysis
Webb R, Abel K, Pickles A and Appleby L;
Commented by , 16 Jun 2005
Aim of the study
In people with schizophrenia the risk for a number of physical diseases is clearly increased. One of the problems that is of major interest and that has been the focus of numerous investigations carried out during several decades is the poor pregnancy outcome of mothers with schizophrenia.
The most severe outcome in this context is death in offspring of parents with psychotic disorders. The current report is a systematic review and meta-analysis of epidemiological studies on the mortality risk among offspring of parents with psychotic disorders. The ultimate aim was to provide evidence on which to base plans for preventive services.
Methods
The authors searched MEDLINE, EMBASE and PsychINFO to identify relevant articles. These articles were first presented in the form of a narrative review, but a meta-analysis (= statistical combination) of the association between maternal psychosis and stillbirth/fetal death was also undertaken. In addition, post hoc post hoc statistical power calculations were performed to analyse the studies ability to detect significant differences.
Results
While some early studies did not find a significant association between maternal schizophrenia and death of offspring, reports published since 1960 usually found higher than expected mortality risk in exposed children. A meta-analysis of six studies yielded an almost twofold higher relative risk of stillbirth/fetal death among offspring of mothers with schizophrenic psychoses.
Discussion
Although most of the studies showed an increased mortality of offspring of mothers with schizophrenic disorders, the authors stress a number of methodological shortcomings. Only two studies were truly population-based. The authors elegantly demonstrate that almost all studies lacked adequate statistical power.
Most of the studies looked only at deaths during a maximum period of one year after birth; cause-specific mortality, and the effects of exposure to specific parental conditions other than schizophrenia have not been sufficiently evaluated.
Of interest would also be an analysis of exposure to paternal versus maternal disorder, i.e. is the mortality risk also increased if the father not the mother has schizophrenia.
Etiological mechanisms explaining the association are not well understood, but factors such as neglect, adverse domestic environments, increased rates of smoking among schizophrenic mothers, low socio-economic status, genetic factors and psychotropic medication toxicity have been discussed. The latter factor is supported by the fact that early studies in the preneuroleptic era often did not find increased offspring mortality.
The authors conclude that further large-scale population-based studies are needed to better understand the role of the above mentioned factors. To date, only general preventive measures such as optimised treatment of the parents’ disease and a greater provision of support to these vulnerable families can be recommended.