BackgroundPost-traumatic Stress Disorder (PTSD) often does not respond to available treatments. Memories are vulnerable to disruption during reconsolidation, and electroconvulsive therapy (ECT) has amnestic effects Objective/hypothesisTo test the use of ECT to disrupt the reconsolidation of traumatic memories as a potential treatment for PTSD MethodsParticipants were adults from the civilian population and were referred for ECT treatment for severe depression with comorbid PTSD symptoms. Twenty-eight participants were randomly assigned to reactivation of a traumatic or non-traumatic memory using audio script driven imagery prior to each ECT treatment. Primary outcomes were change in scores on the Modified PTSD Symptom Scale - Self Report (MPSS-SR) and the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Secondary outcomes included a comparison of the change in heart rate while listening to the script ResultsTwenty-five female patients who completed a post-ECT assessment were included in the analysis. No significant group differences were found in the MPSS-SR or CAPS-5 scores from pre-ECT to post-ECT or 3-month follow-ups. However, both groups improved at post-ECT and 3-month follow up. Partial eta squared estimates of effect size showed large effect sizes for all outcomes (η2 > 0.13). Changes in heart rate were not significantly different between groups or over time ConclusionsECT paired with pre-treatment traumatic memory reactivation was not more effective for treating PTSD symptoms than ECT with non-traumatic memory reactivation. While our primary hypothesis was not supported, our data provides further support for the efficacy of ECT for improving symptoms of PTSD with comorbid depression.ClinicalTrials.gov.https://clinicaltrials.gov/ct2/show/NCT04027452. IdentifierNCT04027452.