The researchers compared single-nucleotide polymorphisms (SNPs) from more than 5,000 subjects who had a diagnosis of cognitive impairment or schizophrenia with those from individuals without a mental illness diagnosis. Levels of genetic overlap were measured by polygenic scores, a sum of trait-associated alleles between two or more chronically ill populations as well as a predictor of an individual's genetic risk for certain diseases. The researchers reported that polygenic scores indicated that schizophrenia was associated with lower cognitive ability than was the case for controls with neither cognitive impairment nor schizophrenia. In addition, multiple SNPs from cognitively impaired subjects significantly overlapped in trait-associated alleles that were found in subjects with schizophrenia.
“Schizophrenia has long been recognized to have a cognitive component,” Anil Malhotra, M.D., senior author and director of psychiatry research at the Zucker Hillside Hospital, told Psychiatric News. “We have demonstrated that the genes that influence cognitive ability also influence schizophrenia, and, as before, clinicians should be attentive to the very real problem of cognitive impairment in schizophrenia.”
To read more about studies involving genetic markers of psychiatric disorders, see the Psychiatric News article, "Genome Analysis Quantifies Risk Across Psychiatric Disorders."