MRM2 and depressive symptom measurement: Because datasets including both brain transcriptomic profiling and rsfMRI mapping in human subjects with depression are not available, we instead used an established method to infer relative gene expression levels in the human brain in 1,458 UK Biobank subjects (537 males) with a history of depression, using each subject’s genotype at the five risk alleles specified above to predict the expression of PRSS16, MRM2, ZKSCAN8P1, and PCDH876.