LAUSR

Background Major Depressive Disorder (MDD) is substantially heritable but has been late to reveal its genetic associations. New data available from UK Biobank (UKB) presents a new opportunity to test for common genetic associations with MDD and to compare different phenotype definitions. Methods We conducted a genome-wide association study of broad and relatively narrow depression phenotypes in UKB and the Psychiatric Genomics Consortium MDD Working Group. Data were meta-analysed and the heritability and genetic correlations between different phenotypic definitions was estimated. Results The full results of our analyses are expected to be available within the next 30 days. Preliminary data analyses suggest that the genetic correlation of all but one depression phenotype in UKB and operationally defined 'clinical' MDD is indistinguishable from 1. Narrower definitions tend to have higher heritabilities, but at the expense of a high number of missing values. Genome-wide significant variants were identified in the first 110 K subjects. We will provide updated results for the meeting. Discussion Our preliminary findings suggest that a broad phenotypic definition of MDD is likely to be the most productive for GWAS studies in future. These definitions include self-declared depression and self-declared treatment with antidepressants amongst others.