AbstractBackgroundThe UK Biobank (UKB) contains data with varying degrees of reliability and completeness for assessing depression. A third of participants completed a Mental Health Questionnaire (MHQ) containing the gold-standard Composite International Diagnostic Interview (CIDI) criteria for assessing mental health disorders.AimsTo investigate whether multiple observations of depression from sources other than the MHQ can enhance the validity of Major Depressive Disorder.MethodsIn participants who did not complete the MHQ (n = 325k), we calculated the number of other depression measures endorsed, e.g. from hospital episode statistics and interview data. We compared cases defined this way to CIDI-defined cases for several estimates: the variance explained by polygenic risk scores (PRS), area under the curve attributable to PRS, SNP-based heritability, and genetic correlations with summary statistics from the Psychiatric Genomics Consortium Major Depressive Disorder (PGC MDD) GWAS.ResultsThe strength of the genetic contribution increased with the number of measures endorsed. For example, SNP-based heritability increased from 7% in cases who endorsed only one measure of depression, to 21% in cases who endorsed four or five measures of depression. The strength of the genetic contribution to cases defined by at least two measures approximated that for CIDI-defined cases. Most genetic correlations between UKB and PGC MDD exceeded 0.7, but there was variability between pairwise comparisons.ConclusionsMultiple measures of depression can serve as a reliable approximation for case-status where the CIDI measure is not available, indicating sample size can be optimised using the entire suite of UKB data.
TU31. GENETIC CONTRIBUTION TO MAJOR DEPRESSIVE DISORDER HETEROGENEITY- FAMILY DESIGNS USING SWEDISH NATIONAL REGISTERS
