Study reveals genetic overlap between schizophrenia and depression
University of Queensland researchers are at the forefront of a ground-breaking study that has found people susceptible to psychiatric disorders such as depression, schizophrenia and bipolar disorder have underlying genetic similarities.
The study, by a worldwide consortium of more than 300 medical researchers in more than 250 institutions, is the first to demonstrate such a link.
The research was led by UQ's Queensland Brain Institute (QBI) researchers Dr Sang Hong Lee and Associate Professor Naomi Wray, and Professor Kenneth Kendler from the Virginia Commonwealth University in the USA.
“We studied the genetic information of more than 75,000 people, using a type of genetic variation called single nucleotide polymorphisms (SNPs),” Associate Professor Wray said.
“A SNP is one of the most common genetic changes and involves the replacement of a single unit that makes up our DNA with another.
“Using about a million SNPs measured on each person, we found evidence of increased genetic similarities between people with the same disorder.
“We also found significant similarities between people suffering from depression, schizophrenia and bipolar disorder.”
Associate Professor Wray said the study supported the hypothesis that mental illnesses could lie along a spectrum, possibly resulting from shared risk factors.
The study is published in the latest issue of Nature Genetics.
“Psychiatric disorders account for about one-third of disability worldwide and cause enormous personal and societal burdens, affecting almost everyone, either directly or through friends and family,” Associate Professor Wray said.
“Despite the impact of these disorders, the underlying causes are mostly unknown.
“Major depression has been a particularly complex challenge, partly because it is so common, but our results now provide clear guidance on what we need to do next to help unravel it,” she said.
“We are now working toward generating a large body of information that will involve assessment of people with and without depression, to further identify genetic risk factors and differences in responses to treatment.”
“Understanding these differences may contribute to personalising treatment options in the long term,” she said.
Associate Professor Wray will work in collaboration with researchers from the Queensland Institute of Medical Research, the University of Sydney Brain and Mind Research Institute, and the South Australia Medical and Health Research Institute to tease apart the genetics of depression.
“Our research is a long way from impacting those affected by psychiatric disorders in terms of diagnosis, prognosis or treatment, but we are glimpsing the potential that advances in genomic technology could have for our understanding of common mental illnesses,” she said.