background Copy number variations (cnvs) are subtle variations in our genetic material. In view of the scientific claim that schizophrenia depends for 40 to 80% on hereditary factors, we need to find out what role the cnvs play in this process.
aim To provide an overview of what is currently known about cnvs and to summarise the implications of this information for the conceptualisation of ‘schizophrenia’ and for the diagnosis and treatment of psychoses.
method We performed a literature search using PubMed.
results The literature consulted contains discussions of 23 cnvs that are associated with an increased risk of psychosis. However, the relationship between the two variables is heterogeneous and pluriform in the sense that cnvs are often associated with several disorders or their penetrance varies considerably under the influence of gene modifiers and environmental factors.
conclusion Research into cnvs demonstrates that the relationship between psychosis and heredity is of a even more subtle nature than the two pioneers Kraepelin and Rüdin had been able to foresee. It is to be expected that in the near future research will contribute to a deconstruction of the schizophrenia concept, to a blurring of the hitherto sharply defined boundaries between different (particularly severe) mental disorders and to the introduction of genetic counselling into regular psychiatric diagnostic procedures.