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EXPERT REACTION: Different mental health disorders linked by similar DNA

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Anorexia, obsessive-compulsive disorder and schizophrenia all share common genetics, according to a massive DNA analysis by Australian and international researchers which found the same genes were connected to a range of psychiatric disorders. The researchers were looked at the genetic risks for 25 brain disorders in almost 900,000 people to try and find common genes impacting everything from epilepsy to autism and depression. They found that people with psychiatric disorders shared many common genes, although the genetic risk most commonly found in both Autism Spectrum Disorder and Tourette syndrome (TS) was different to other psychiatric disorders. They also found that personality traits such as neuroticism were linked to specific psychiatric diseases, including depression and anxiety. The researchers found almost no genetic overlap among neurological diseases, such as Alzheimer’s disease and multiple sclerosis.

Journal/conference: Science

Organisation/s: QIMR Berghofer Medical Research Institute, The University of Queensland, Queensland University of Technology (QUT), The University of Melbourne, Florey Institute of Neuroscience and Mental Health, University of Newcastle, Flinders University, NeuRa, University of New South Wales, University of Adelaide, University of Sydney,

Funder: National Institute of Mental Health, the Orion Farmos Research Foundation and the Fannie and John Hertz Foundation.

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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Professor Murray Cairns is from the School of Biomedical Sciences and Pharmacy at the University of Newcastle. He is an author on the paper.

This outstanding achievement of international collaboration shows unequivocally that all the common psychiatric disorders have a very significant genetic correlation with each other. In other words, they are deeply connected genetically with a large proportion of liability shared between psychiatric/behavioural disorders, such as schizophrenia, bipolar disorder and major depression. This raises the question of why they present so differently? By contrast, when it came to common neurological disorders, such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis, there was no correlation between them or the behavioural disorders. The only exception was migraine, which, surprisingly, was slightly correlated with psychiatric disorders even though it is classified as neurological.

Other interesting findings related to the genetic correlations with other quantitative traits such as educational achievement and neuroticism. Surprisingly, early life educational attainment was positively correlated with a number of psychiatric illnesses, which tend to occur early in life, while being negatively correlated with neurological disorders such as Alzheimer’s disease, which occurs late in life. My connection to this research is through the genetic analysis of the Australian Schizophrenia Research Bank cohort, which was part of the schizophrenia working group of the psychiatric genomics consortium data used in the current study

Last updated: 22 Jun 2018 11:51am
Declared conflicts of interest:
Prof Cairns’ lab did the genotyping (DNA-microarray) of approximately 600,000 genomic variants for the Australian contribution to the schizophrenia group (~800 samples).
Professor Christel Middeldorp is a Professor of Child and Youth Psychiatry in the Child Health Research Centre at the University of Queensland. She is an author on the paper.

This study shows that psychiatric disorders, such as bipolar disorder, depression and schizophrenia, often share a genetic background, while they are not so much genetically associated to neurological disorders.

Last updated: 22 Jun 2018 11:49am
Declared conflicts of interest:
Prof Middeldorp is an author of this paper and contributed to the research.

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