qPCR results showed that knockdown of Homer1 improved the expression of inflammation‐related markers IL‐1β, TNF‐α, IL‐10, and depression‐related markers ERCCL2, SLC6A4, and GAD1 in primary neurons, both in the PTSD group and in the TBI+Hcort group. This evidence concerns the gene SLC6A4 and major depressive disorder.