There is no evidence of genetic overlap between risk for schizophrenia and brain volume measures, according to researchers in a global study that examined the genes that drive the development of schizophrenia.
That was the key finding in a collaborative study involving nearly 600 researchers from more than 350 institutions, including Georgia State University, and published in journal Nature Neuroscience.
Brain volumes are affected by genetics and schizophrenia has a genetic basis, and having schizophrenia correlates with smaller subcortical brain volumes. The research team investigated whether or not smaller brain volumes and schizophrenia share any genetic effects.
"We looked at subcortical volumes to determine whether the genes that increase risk for schizophrenia affect the hippocampus, thalamus and amygdala, and whether the genes that affect the volume of those areas increase risk for schizophrenia," said Jessica Turner, associate professor of psychology and neuroscience at Georgia State and an author of the study.
"Unfortunately, our results indicate no overlap, so we are going to have to look elsewhere to find the genetic effects on brain measures causing the development of schizophrenia. But what makes this research so exciting is that the international scientific community is capable of working together on a massive scale, across country borders, to examine these questions that affect so many of us."
The large-scale collaboration was required in order to analyze the very large sample of brain scans from almost 12,000 individuals from around the world. This study is the first of many more in other disorders such as depression, attention deficit disorder or bipolar disorder.
"We would rather have found that there is a set of genes that drive both the development of schizophrenia and a smaller thalamus, of course," added Turner. "But we will continue analysis on other parts of the brain, including the frontal cortex and temporal cortex, and a number of other approaches."
The study offers a roadmap for future research into possible associations between brain volume measures and known genetic risk factors.