The aim of this study is to identify relationships between the expression levels of selected molecular biomarkers—interleukin 18 (IL-18), IRE1 kinase, phosphorylated ERK (pERK), and transcription factor ATF6—and the results obtained on the individual subscales of the Courtauld Emotional Control Scale in patients diagnosed with post-traumatic stress disorder. The gene discussed is EIF2AK3; the disease is post-traumatic stress disorder.