Eye Movement Desensitization and Reprocessing Therapy in Persons With Personality Disorders: A Randomized Clinical Trial.

Importance: Adverse childhood experiences contribute to the development of personality disorders (PDs). Although trauma-focused interventions are effective for posttraumatic stress disorder (PTSD), their effect on PD symptoms is less established. Objective: To evaluate the effectiveness of eye movement desensitization and reprocessing (EMDR) therapy in reducing PD symptoms compared with a waiting list, regardless of PTSD status. Design, Setting, and Participants: This 2-arm, multicenter, single-blind, randomized clinical trial was performed in the specialized outpatient departments of 2 clinics in the Netherlands from February 22, 2021, to October 2, 2024. Participants included 159 patients with PD diagnosed using the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD). Data were analyzed based on intention to treat. Intervention: Ten 90-minute EMDR sessions for 5 weeks, targeting traumatic and adverse memories linked to PD symptoms. Main Outcomes and Measures: Pretreatment, posttreatment, and 3-month follow-up assessments using the Assessment of DSM-IV Personality Disorders (ADP-IV), SCID-5-PD, Level of Personality Functioning Scale (LPFS), and Difficulties in Emotion Regulation Scale (DERS). Results: Among the 159 patients included in the analysis, mean (SD) age was 35.4 (12.0) years, and 130 were female (81.8%). Seventy-nine participants were randomized to the EMDR group and 80 to the waiting-list control group. Four participants (5.1%) dropped out of the EMDR group, and 16 (20.3%) were early completers, without adverse events. EMDR therapy outperformed the waiting-list condition for ADP-IV post treatment (β, -37.93 [95% CI, -52.54 to -23.33]; P < .001; Cohen d = 0.31 [95% CI, -0.05 to 0.66]) and at follow-up (β, -45.73 [95% CI, -64.90 to -26.56]; P < .001; Cohen d = 0.46 [95% CI, 0.10-0.82]), SCID-5-PD post treatment (β, -3.65 [95% CI, -5.87 to -1.42]; P = .002; d = 0.48 [95% CI, 0.14-0.82]) and at follow-up (β, -3.70 [95% CI, -7.10 to -0.30]; P = .03; Cohen d = 0.61 [95% CI, 0.25-0.97]), LPFS post treatment (β, -3.13 [95% CI, -4.86 to -1.41]; P < .001; Cohen d = 0.31 [95% CI, -0.05 to 0.67]) and at follow-up (β, -3.62 [95% CI, -5.96 to -1.28]; P = .003; Cohen d = 0.43 [95% CI, 0.06-0.79]), and DERS post treatment (β, -9.03 [95% CI, -14.90 to -3.15]; P = .003; Cohen d = 0.35 [95% CI, -0.01 to 0.71]) and at follow-up (β, -11.73 [95% CI, -19.90 to -3.55]; P = .005; Cohen d = 0.62 [95% CI, 0.25-0.98]). PD remission was more common in the EMDR than control groups both post treatment (ADP-IV, 38.3% vs 6.8%; SCID-5-PD, 33.3% vs 7.8%) and at follow-up (ADP-IV, 45.4% vs 5.9%; SCID-5-PD, 44.1% vs 15.8%). Conclusions and Relevance: In this randomized clinical trial of 159 patients with PD, EMDR therapy led to significant reduction in PD symptoms, with 30 (44.1%) achieving remission. These findings support the potential of EMDR therapy for PD treatment and encourage further confirmatory research. Trial Registration: Netherlands Trial Register: NL9078.