Genes link bipolar, schizophrenia, once thought unrelated
Scientists have discovered the connection between bipolar disorder and schizophrenia, prompting the two disorders to be classified together on the same disease list.
Using data from nearly 10,500 patients across 50 studies, researchers looked at how the genes that underlie the two disorders — and also Alzheimer and Parkinson disease — shared similarities in disease risk.
Bipolar disorder and schizophrenia are two of the most common brain disorders.
Schizophrenia is associated with long-term disability, and a quarter of patients are expected to die by their late 30s.
Bipolar disorder is often seen as a mental illness of the “brain illness” variety.
The new findings, published in the journal Molecular Psychiatry, suggest that bipolar disorder and schizophrenia may share some biological processes.
“By reviewing the genomes of patients with idiopathic schizophrenia and bipolar disorder, we’ve discovered a significant amount of molecular similarity between them,” said lead study author Christopher Eberhart, PhD, a psychiatrist at Stanford University.
“These findings suggest that we don’t need a new disease for schizophrenia and bipolar disorder to be diagnosed as one disorder,” Eberhart added.
More than 20 million Americans have bipolar disorder, according to the World Health Organization.
Researchers from the University of California at San Francisco, Washington University in St. Louis and University of California at Berkeley in the US studied data from nearly 10,500 patients across 50 studies.
To identify genes that are related to the two psychiatric disorders, the researchers used “genome-wide association” and “meta-analysis,” a two-pronged approach in which a team of researchers reviews thousands of genetic association studies — or “meta-analyses” — which combine genetic information from up to hundreds of studies into a single analysis.
The first prong of the analysis used data from the National Institute of Mental Health Genetic Association Information Network, which consists of over 5,000,000 samples gathered from individuals who have been diagnosed with bipolar disorder or schizophrenia, or both.
The second part of the analysis used data from the Psychiatric Genomics Consortium, a collaboration of researchers with access to more than 100,000 genomic data sets.
The researchers found that there was a significant amount of shared genetic similarities in the two disorders.