Abstract
BACKGROUND: Eye movement desensitization and reprocessing (EMDR) is recommended by major health organizations for trauma treatment, but its efficacy for borderline personality disorder (BPD) remains unestablished. This study aims to evaluate EMDR's effectiveness in treating BPD through a randomized controlled trial (RCT) and compare its outcomes with cognitive behavioral therapy (CBT). METHODS: A total of 76 individuals participated in the RCT, with 18 patients (78% female) completing the study. Participants were randomly assigned to receive either EMDR (n = 8) or CBT (n = 10) via teletherapy sessions. Trauma symptoms were assessed using the international trauma questionnaire (ITQ), BPD symptoms were assessed using the Personality Assessment Inventory-Borderline Features Scale (PAI-BOR), and post-traumatic growth (PTG) was assessed using the post-traumatic growth inventory (PTGI). Additionally, attentional evaluations were conducted at behavioral and electroencephalographic levels through an oddball paradigm. A final comparison was made between a participant who did not complete the therapeutic process and a participant who did. RESULTS: Both EMDR and CBT treatments significantly improved trauma and BPD symptoms, as well as post-traumatic growth. The effect size was moderate for ITQ (η(2) = 0.615) and PTGI (η(2) = 0.610), and low for PAI-BOR (η(2) = 0.147). Symptomatic participants showed a decrease in ITQ (p = 0.006) and PAI-BOR (p = 0.047) scores, and an increase in PTGI scores (p = 0.028). CONCLUSIONS: Both EMDR and CBT significantly improved trauma and BPD symptoms, as well as post-traumatic growth. Additionally, EMDR showed benefits in response accuracy and speed, with a correct response rate of 97% when comparing two participants (with and without therapy). However, completely clean electroencephalography (EEG) data were not obtained from both participants for a deeper comparison. CLINICAL TRIAL REGISTRATION: The study was registered at https://doi.org/10.1186/ISRCTN91146045, registration number: ISRCTN91146045, registration date: 21 May 2021.