Gene expression differences in PTSD are uniquely related to the intrusion symptom cluster: A transcriptome-wide analysis in military service members.

•Gene expression differences were almost entirely attributed to intrusion symptoms.•No gene expression differences were attributed to the other PTSD symptom clusters.•PTSD-like symptoms due to comorbid conditions may be represented by different genes.•Immune systems were upregulated in PTSD and downregulated with symptom reduction.