Finally, we explored how well the definitions of depression in the UK Biobank predict strictly defined, CIDI-based MDD in independent cohorts, using data from 23 MDD cohorts in the latest data freeze from the MDD Working Group of the Psychiatric Genomics Consortium (PGC29-MDD5,51; Supplementary Note, Supplementary Table 21 and Supplementary Fig. 7). We constructed polygenic risk scores (PRSs) on each definition of depression in the UK Biobank (Methods) and examined their prediction in each of the PGC29-MDD cohorts. Of note, PRS from all definitions of depression in the UK Biobank, whether minimally or strictly phenotyped, accounted for a small proportion of variation in disease status in PGC29-MDD (Supplementary Table 22). We observed the following features.
