Objectives: The present study aimed to investigate the effectiveness of eye movement desensitization and reprocessing (EMDR) therapy in response inhibition and cognitive flexibility of veterans with PTSD.

Methods: This quasi-experimental research adopted a pretest-posttest follow-up control group design. The statistical population included all the veterans supported by the Foundation of Martyrs and Veterans Affairs (FMVA) in Ahvaz, Khuzestan Province (Iran) in 2021. The purposive sampling method was employed to select 30 veterans who visited the psychological service centers affiliated with the FMVA of Ahvaz. They were then randomly assigned to the experimental (n = 15) and control (n = 15) groups. The participants in the experimental group received ten 60-minute EMDR therapy sessions held by the researcher, who underwent specialized training at the FMVA Counseling Center in Boustan Hospital. The participants in the control group received no intervention. The cognitive flexibility questionnaire and response inhibition scale were used to collect data. The analysis of covariance (ANCOVA) was used for data analysis in SPSS 24.

Results: In the experimental group, the posttest and follow-up scores of response inhibition (response time) and cognitive flexibility showed significant improvements compared to pretest scores (P < 0.001).

Conclusions: Hence, EMDR therapy improved cognitive flexibility and response inhibition in veterans with PTSD. As a result, EMDR therapy can be employed to enhance the psychological characteristics of veterans with stress.”