A new study has found that at least three psychiatric disorders appear to share similar patterns of gene activity. The study looked at messenger RNA in patients with autism, schizophrenia and bipolar disorder, and found that there was a significant overlap in the genetic makeup of those diagnosed with the conditions. Previous studies have identified common genes between these disorders. However, this is the first to look at the impact the genes have on brain activity.
The study also looked at patients without symptoms of mental illness and those suffering from depression and alcoholism to form a comparison. Dr. Daniel Geschwind, a neurogeneticist at the University of California at Los Angeles and a lead author of the study commented that “All of these disorders have a genetic contribution to them that’s quite substantial, and yet that contribution is not simple. It’s very complex.”
Dan Arking, a geneticist and associate professor of medicine at the Johns Hopkins University School of Medicine, who was not involved in the study added “There does seem to be quite a bit there suggesting that there is perhaps more in common than we would have guessed,” “We had done a study a couple of years back where we looked at schizophrenia, bipolar and autism, and we saw an overlap between schizophrenia and autism, but we didn’t see it with bipolar so much.”
During the study, researchers found that there were four types of genes that were less active in the three disorders and one set of genes that was overactive. This finding suggests that a shared dysfunction in how brain cells communicate with each other could be a contributing factor to the illnesses. In addition to this, the study found that microglia cells were overly active in the patients with autism. These cells are heavily involved in the regulation of synapses during early development, which could provide an explanation as to why autism is usually diagnosed in childhood.
Participants who had been diagnosed with depressive disorders also shared a common set of markers, which are involved in the hormonal balances in the brain. “I would say that depression has its own signature, to simplify it,” Geschwind said. “Although globally it overlaps somewhat with schizophrenia and bipolar, it also has a component that is a dysregulation of hormonal signaling.”
Arking went on to add that this study could help to provide better insight in the way the brain functions in those with psychiatric disorders, and lead to improved treatments in the future. “Using this approach to try to identify pathways is potentially quite important because it gives you more specific drug targets. If this pathway is involved, I can give a drug that affects the pathway and not worry so much about finding a drug for each specific gene,” he said.