They compared the samples with samples from brains of people without mental illness.
- Researchers have found that certain psychiatric disorders like autism, schizophrenia and bipolar disorder share some physical characteristics at the molecular level, specifically, patterns of gene expression in the brain, The Indian Express says.
"These findings provide a molecular, pathological signature of these disorders, which is a large step forward", said senior study author Daniel Geschwind.
"The major challenge now is to understand how these changes arose", Geschwind said.
The researchers identified several genetic variations associated with a higher risk of developing these psychiatric disorders; however, DNA alone does not account for the whole phenomenon.
Gene expression refers to cells' conversion of genetic instructions into proteins. Gandal is an assistant professor of psychiatry and biobehavioral sciences at UCLA.
The molecular pathology revealed significant overlap between distinct disorders, like schizophrenia and autism, but also specificity, with major depression showing molecular changes are absent in other disorders.
Scientists examined the RNA in 700 tissue samples from the brains of deceased subjects who had schizophrenia, autism, bipolar disorder, major depressive disorder or alcohol abuse disorder, and they contrasted them with the tissue samples obtained from the brains of subjects without psychiatric disorders.
"We show that these molecular changes in the brain are connected to underlying genetic causes, but we don't yet understand the mechanisms by which these genetic factors would lead to these changes", Geschwind said in a university news release.