The Psychiatry, Mental Health and Addictions research group at Vall d’Hebron Institute of Research (VHIR) has taken part in the largest study so far undertaken on psychiatric diseases. The study, which has been published today in "http://www.nature.com/ng/journal/vaop/ncurrent/abs/ng.2711.html" Nature Genetics, has analyzed the five most common psychiatric diseases with more personal and social impact (schizophrenia, bipolar disorder, major depression, Disorder and Attention Deficit Hyperactivity Disorder –ADHD- and autism), and has determined the genetics of each one of them, thanks to the huge sample of individuals included in this work. Besides, one of the most important findings of the study is that there is also a genetic burden shared among some of these pathologies. VHIR’s researchers have led the Spanish team that participates in this international consortium: the International Multicentre persisten ADHD Genetics CollaboraTion (IMpACT). This group, in which also participates Dr. Bru Cormand, from the Genetic Department at University of Barcelona (UB) and the Rare Diseases CIBER Network (CIBERER), and Dr. Mónica Bayés, from the National Centre of Genomic Analysis (CNAG-PCB), has contributed to the study with genetic data from patients and individuals control, collected thanks to another specific study of ADHD done thanks to La Marató de TV3 in 2008.This investigation has analyzed for the first time data from several GWAS studies in psychiatric disorders to determine if there are common genetic factors among these pathologies. Previous studies done with samples from twins or families had determined that there was a genetic burden in these pathologies but just in these kinship cases. Now, this study has quantified the genetic basis associated to these diseases with a sample of more than 75.000 individuals. There are genetic causes which can be attributed to chromosomal alterations or other alterations, but this work has investigated the heritability only associated to single nucleotide polymorphisms of the DNA chain. Thanks to methodologies such as GWAS it is possible to study millions of SNPs from each individual and finding evidence of genetic similarities among people with the same disease. “Results have shown that patients with psychiatric pathologies share more SNPs among them than with the control group. Thus, the study has identified which is the genetic burden associated to SNP in each disease”, explains Dr. Marta Ribasés, from the Laboratory of Genetic Psychiatry at VHIR and the Psychiatric Service at Vall d’Hebron University Hospital (HUVH). In patients with schizophrenia, the heritability associated to SNP is the 23%, in patients with bipolar disease, of the 25%, in the case of major depression, of the 21%, in ADHD of the 28%, and in autism, of the 17%.