A massive undertaking by the Brainstorm Consortium to analyze the genomes of nearly 900,000 people has revealed important insights into the genetic overlap among some psychiatric diseases, as well as among personality traits. Here, Verneri Anttila and colleagues sought to explore the genetic underpinning of 25 brain disorders (both neurological and psychiatric) by analyzing the genomes of about 215,500 patients and 650,000 healthy participants.
Three additional disorders (epilepsy, migraine, and ischemic stroke) were also included. While the researchers found almost no genetic overlap among neurological diseases, such as Alzheimer’s disease and multiple sclerosis, they found much overlap among psychiatric diseases. Anorexia nervosa, obsessive-compulsive disorder, and schizophrenia demonstrated the most overlap, the authors say, and schizophrenia was found to correlate with most of the psychiatric disorders in general. Notably, the common variant risk of both Autism Spectrum Disorder and Tourette syndrome (TS) appears to be distinct from the influence of other psychiatric disorders, the authors say. The only non-psychiatric disorder that overlapped with psychiatric disorders was migraine, the authors report; migraines may share some of their genetic architecture with TS, attention-deficit/hyperactivity disorder and Major Depressive Disorder (MDD). The data further reveal several personality traits that are associated with specific psychiatric diseases; for example, neuroticism was linked to MDD, anxiety disorders, TS and more. Intriguingly, the data also uncover a significant correlation between coronary artery disease, as well as the two stroke-related phenotypes ischemic stroke and early onset stroke, with MDD. In five out of eight of the psychiatric disorders they studied, Anttila et al. identified a genetic correlation with at least one or more cognitive measures (i.e., college attainment, intelligence), possibly suggesting the existence of a link between cognitive performance in early life and the genetic risk for psychiatric disorders, the authors say.