Eleven psychiatric disorders were found to have similar genetic makeup, which explains why an individual is more likely to be diagnosed with multiple psychiatric disorders in their lifetime, according to a study overseen by the University of Colorado Boulder.
Research founded from the Psychiatric Genomics Consortium, UK Biobank, iPSYCH and 23andMe has been collected by a large team of international collaborators to create four categories to demonstrate how the genetic makeup common to these psychiatric disorders affects an individual on a biobehavioral, functional genomics and molecular genetic basis. Those four categories are psychotic, neurodevelopmental, internalizing and compulsive.
The research results have been published in Nature Genetics.
Dr. Andrew Grotzinger, who was part of an international team and is a CU Boulder professor, explained that after analyzing the data collected, researchers discovered there are thousands of genes that activate disorders and that within those disorders, there is an overlap between shared genetics.
From there, the team studied the genome-wide association studies’ summary statistics to examine how each genetic variant is connected to the disorders. They discovered there are similarities between the genes connected with the disorders and an individual’s behavior as it relates to socioeconomic, health and disease, anthropomorphic, personality, cognitive and risky behavior issues.
For example, they found that if someone has a low body mass index it can be linked to compulsive disorders. Anorexia nervosa, obsessive compulsive disorder and Tourette syndrome are associated with “genetic predispositions to have a lower body mass index (which can) increase your risk for these three subsets of disorders and not just the disorder that’s actually clinically defined by a low body weight (anorexia nervosa),” Grotzinger stated.
Internalizing disorders such as post-traumatic stress disorder, major depression and anxiety can be linked with genetic predispositions such as having lower back pain, asthma and coronary artery disease.
“It could be that (you have) genetic predispositions to have these disorders (that) are associated with lifestyle factors that increase your risk for these or that something like chronic back pain itself leaves you more predisposed to feel depressed” Grotzinger said.
“So it’s not really clear what the pathway is. Like, are you depressed, and then it’s hard for you to get out of bed, that sort of thing, and then you kind of are more at risk to develop lower back pain or does lower back pain just make people depressed?”
In addition, this study has also helped researchers conclude why certain disorders affect an individual’s health and personality traits. For example, internalizing disorders that are linked to major depression, anxiety and PTSD and compulsive disorders that are tied to anorexia, obsessive compulsive disorder and Tourette syndrome all share the common factor that individuals tend to have lower body mass index as well as have characteristics such as neuroticism, openness and extraversion.
Psychotic illnesses, which include bipolar disorder and schizophrenia, were found to have genetic pathways with these specific genes: Excitatory and GABAergic neurons.
“So what this is doing — is it’s starting to kind of shed light on the specific biological pathways that might be shared across these disorders; namely, these specific neurons that are sort of critical and just brain signaling pathways,” Grotzinger said.
With these findings, Grotzinger hopes to be able to identify what the specific genetic risk pathways are so an individual can be diagnosed and treated more efficiently. The goal is to be able to give an individual one diagnosis and treatment for the disorders they have instead of multiple, if possible.
Currently, an individual cannot be diagnosed with bipolar and schizophrenia disorder. However, these two disorders have an overlap in their genetic makeup — meaning that an individual can experience symptoms from both disorders.
Grotzinger hopes in the future diagnoses can be made “a little less sort of by the book.” In addition, there also may be a possibility of treating certain diagnoses with psychotherapy versus prescription medicines.
The research team only analyzed the genetic variation that showed up in at least 1% of the population.
“That really rare stuff might be really important. And it’s something that we’re just now getting to the point that we can start to look at,” Grotzinger said.