Common causes for ASD, schizophrenia and bipolar

New research suggests there may be common causes for autism spectrum disorders (ASD), schizophrenia and bipolar disorder, however the biological reasons underlying this relationship are still unknown.  

Researchers from King’s College London’s Institute of Psychiatry, the University of North Carolina (USA) and the Karolinska Institutet (Sweden) used population registers in Sweden and Israel to examine whether a family history of schizophrenia, bipolar disorder, or both were risk factors for ASD. Researchers examined histories of schizophrenia or bipolar disorder in first-degree relatives of patients who met the criteria for ASD.

Dr Avi Recihenberg, co-author of the paper published in Archives of General Psychiatry and who led the analysis of the Israel data, says: "These findings are important because if ASD, schizophrenia and bipolar disorder have some common causes, they may be more similar than we currently understand. 

“This relationship has never been fully appreciated but it may change how researchers and clinicians think about these disorders. It does not necessarily suggest that these disorders should be lumped into an aggregate classification. But, some individuals with schizophrenia have developmental histories not inconsistent with ASD, and therefore, in some cases, early ASD might be indicating later manifestation of schizophrenia."

In the Swedish sample, the presence of schizophrenia in parents meant that individuals were 2.9 times more likely to have ASD. The presence of schizophrenia in a sibling meant that individuals were 2.6 times more likely to have ASD in the Swedish sample, and 12 times more likely in the Israeli group. Bipolar disorder showed a similar pattern of association but of a lesser magnitude

The Swedish Council for Working Life and Social Research, the Swedish Research Council and the Beatrice and Samuel A. Seaver Foundation funded this study. 

For full paper: 'Family history of schizophrenia and bipolar disorder as risk factors for autism' (2nf July) Archives of General Psychiatry. doi:10.1001/archgenpsychiatry.2012.730. 

For further media information, please contact Seil Collins, Press Officer, Institute of Psychiatry, email: seilcollins@kcl.ac.uk or tel: 0207 848 5377