The BiDirect cohort is a prospective observational study established to investigate the relationship between depression and cardiovascular disease 61. Cases were recruited from psychiatric and psychosomatic hospitals and residential psychiatrists’ practices in and around Münster and were required to be between the ages of 35 and 65 and had to be receiving in-patient or out-patient treatment for acute depression. A detailed description of the diagnostic criteria used in this cohort is provided by Teismann, et al. 61. Controls were randomly ascertained from the local population. The quality control procedures and genome-wide association analysis of this cohort was also conducting the same pipeline as used in Wray, et al. 9. There were a total of 811 acute depression cases and 469 controls used to calculate the proportion of variance explained using polygenic risk scores in the BiDirect cohort. The best thresholds for the meta-analysis PRS (P ≤ 0.5; 24,964 SNPs) and Wray PRS (P ≤ 0.05; 62,144 SNPs) were each used to test for an association with MDD in the BiDirect cohort.
