Efficacy of Eye-Movement Desensitization and Reprocessing for Patients with Posttraumatic-Stress Disorder: A Meta-Analysis of Randomized Controlled Trials Ying-Ren Chen 1 , Kuo-Wei Hung 2." , Jui-Chen Tsai 3." , Hsin Chu 4,5 , Min-Huey Chung 1 , Su-Ru Chen 6 , Yuan- Mei Liao 1 , Keng-Liang Ou 7,8,9,10 , Yue-Cune Chang 11 , Kuei-Ru Chou 1,3,12 * 1 Graduate Institute of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan, and Taoyuan Armed Forces General Hospital, Longtan, Taiwan, 2 Division of Neurology, Department of Internal Medicine, Yuan’s General Hospital, Kaohsiung, Taiwan, 3 Department of Nursing, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan, 4 Institute of Aerospace and Undersea Medicine, School of Medicine, National Defense Medical Center, Taipei, Taiwan, 5 Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, 6 School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan, 7 Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan, 8 Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei, Taiwan, 9 Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei, Taiwan, 10 Department of Dentistry, Taipei Medical University-Shuang-Ho Hospital, Taipei, Taiwan, 11 Department of Mathematics, Tamkang University, Tamsui, Taiwan, 12 Psychiatric Research Center, Taipei Medical University Hospital, Taipei, Taiwan Abstract Background: We performed the first meta-analysis of clinical studies by investigating the effects of eye-movement desensitization and reprocessing (EMDR) therapy on the symptoms of posttraumatic stress disorder (PTSD), depression, anxiety, and subjective distress in PTSD patients treated during the past 2 decades. Methods: We performed a quantitative meta-analysis on the findings of 26 randomized controlled trials of EMDR therapy for PTSD published between 1991 and 2013, which were identified through the ISI Web of Science, Embase, Cochrane Library, MEDLINE, PubMed, Scopus, PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature electronic databases, among which 22, 20, 16, and 11 of the studies assessed the effects of EMDR on the symptoms of PTSD, depression, anxiety, and subjective distress, respectively, as the primary clinical outcome. Results: The meta-analysis revealed that the EMDR treatments significantly reduced the symptoms of PTSD (g = 20.662; 95% confidence interval (CI): 20.887 to 20.436), depression (g = 20.643; 95% CI: 20.864 to 20.422), anxiety (g = 20.640; 95% CI: 20.890 to 20.390), and subjective distress (g = 20.956; 95% CI: 21.388 to 20.525) in PTSD patients. Conclusion: This study confirmed that EMDR therapy significantly reduces the symptoms of PTSD, depression, anxiety, and subjective distress in PTSD patients. The subgroup analysis indicated that a treatment duration of more than 60 min per session was a major contributing factor in the amelioration of anxiety and depression, and that a therapist with experience in conducting PTSD group therapy was a major contributing factor in the reduction of PTSD symptoms. Citation: Chen Y-R, Hung K-W, Tsai J-C, Chu H, Chung M-H, et al. (2014) Efficacy of Eye-Movement Desensitization and Reprocessing for Patients with Posttraumatic-Stress Disorder: A Meta-Analysis of Randomized Controlled Trials. PLoS ONE 9(8): e103676. doi:10.1371/journal.pone.0103676 Editor: Linda Chao, University of California, San Francisco, United States of America Received March 21, 2014; Accepted July 1, 2014; Published August 7, 2014 Copyright: ß 2014 Chen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by the Taiwan National Science Council (project no. NSC102-2314-B-038-036) and Yuan’s General Hospital (103YGH-TMU-03). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * Email: [email protected]. These authors contributed equally to this work. " KWH and JCT are first authors on this work. Introduction Eye movement desensitization and reprocessing (EMDR) was developed by Francine Shapiro [1], and is a complex and specific desensitizing treatment method. EMDR therapy desensitizes patients to anxiety and integrates information processing [1]. Adaptive information processing is the theoretical framework for EMDR, because it addresses factors related to both pathology and personality development. Adaptive information processing con- tributes to orienting responses (ORs), which involve retrieving information from previous experiences and integrating them into a positive emotional and cognitive schema [2]. A dual-attention stimulus, such as eye movement, is an integral component of EMDR because it induces certain physiological conditions that activate information processing. Eye movements may unblock the information-processing centers of the brain, creating a connection PLOS ONE | www.plosone.org 1 August 2014 | Volume 9 | Issue 8 | e103676
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Efficacy of Eye-Movement Desensitization andReprocessing for Patients with Posttraumatic-StressDisorder: A Meta-Analysis of Randomized ControlledTrialsYing-Ren Chen1, Kuo-Wei Hung2.", Jui-Chen Tsai3.", Hsin Chu4,5, Min-Huey Chung1, Su-Ru Chen6, Yuan-
Mei Liao1, Keng-Liang Ou7,8,9,10, Yue-Cune Chang11, Kuei-Ru Chou1,3,12*
1 Graduate Institute of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan, and Taoyuan Armed Forces General Hospital, Longtan, Taiwan, 2 Division of
Neurology, Department of Internal Medicine, Yuan’s General Hospital, Kaohsiung, Taiwan, 3 Department of Nursing, Taipei Medical University-Shuang Ho Hospital, Taipei,
Taiwan, 4 Institute of Aerospace and Undersea Medicine, School of Medicine, National Defense Medical Center, Taipei, Taiwan, 5 Department of Neurology, Tri-Service
General Hospital, National Defense Medical Center, Taipei, Taiwan, 6 School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan, 7 Graduate Institute
of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan, 8 Research Center for Biomedical Devices and
Prototyping Production, Taipei Medical University, Taipei, Taiwan, 9 Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei,
Taiwan, 10 Department of Dentistry, Taipei Medical University-Shuang-Ho Hospital, Taipei, Taiwan, 11 Department of Mathematics, Tamkang University, Tamsui, Taiwan,
12 Psychiatric Research Center, Taipei Medical University Hospital, Taipei, Taiwan
Abstract
Background: We performed the first meta-analysis of clinical studies by investigating the effects of eye-movementdesensitization and reprocessing (EMDR) therapy on the symptoms of posttraumatic stress disorder (PTSD), depression,anxiety, and subjective distress in PTSD patients treated during the past 2 decades.
Methods: We performed a quantitative meta-analysis on the findings of 26 randomized controlled trials of EMDR therapy forPTSD published between 1991 and 2013, which were identified through the ISI Web of Science, Embase, Cochrane Library,MEDLINE, PubMed, Scopus, PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature electronicdatabases, among which 22, 20, 16, and 11 of the studies assessed the effects of EMDR on the symptoms of PTSD,depression, anxiety, and subjective distress, respectively, as the primary clinical outcome.
Results: The meta-analysis revealed that the EMDR treatments significantly reduced the symptoms of PTSD (g = 20.662;95% confidence interval (CI): 20.887 to 20.436), depression (g = 20.643; 95% CI: 20.864 to 20.422), anxiety (g = 20.640;95% CI: 20.890 to 20.390), and subjective distress (g = 20.956; 95% CI: 21.388 to 20.525) in PTSD patients.
Conclusion: This study confirmed that EMDR therapy significantly reduces the symptoms of PTSD, depression, anxiety, andsubjective distress in PTSD patients. The subgroup analysis indicated that a treatment duration of more than 60 min persession was a major contributing factor in the amelioration of anxiety and depression, and that a therapist with experiencein conducting PTSD group therapy was a major contributing factor in the reduction of PTSD symptoms.
Citation: Chen Y-R, Hung K-W, Tsai J-C, Chu H, Chung M-H, et al. (2014) Efficacy of Eye-Movement Desensitization and Reprocessing for Patients withPosttraumatic-Stress Disorder: A Meta-Analysis of Randomized Controlled Trials. PLoS ONE 9(8): e103676. doi:10.1371/journal.pone.0103676
Editor: Linda Chao, University of California, San Francisco, United States of America
Received March 21, 2014; Accepted July 1, 2014; Published August 7, 2014
Copyright: � 2014 Chen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permitsunrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by the Taiwan National Science Council (project no. NSC102-2314-B-038-036) and Yuan’s General Hospital (103YGH-TMU-03).The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
38,39,40] did not report blinding. Data completeness was
Table 1. Cont.
Study Intervention DesignSample size(patients)
Interventioncharacterization Outcome
Studyquality/
(Experimental/Control)Cochranetool
Karatziaset al. (2011)
EMDR/EFT RCT Total N: 46 Number of timestreated: 8
self-rating scales 8/
CompleteN (T/C): 23/23
Treatment duration(min): 60
Symptoms (PCL-C) AA:low
Mean age(yr): 40.6
Each group size(people): individual
Depression (HADS-D) AC:unclear
EMDR therapist: - Anxiety (HADS-A) BAO:low
PTSD groupexperience: disclosed
non-self-rating scales IO:high
Symptoms (CAPS) SRO:low
Instruments: M-PTSD = Mississippi scale for combat-related PTSD; IES = Impact of Event Scale; SI-PTSD = Davidson’s Structured Interview for PTSD; PSS-SR = PTSDSymptom Scale, Self-Report; CAPS = Clinician-Administered PTSD Scale; PCL-C = PTSD Checklist; SR = self-report; Child PTS-RI = Child Posttraumatic Stress ReactionIndex; CROPS = Child Report of Posttraumatic Symptoms; PENN = Penn Inventory for Posttraumatic Stress Disorder; CRI = Children’s Reaction Inventory; PTSS-C =Posttraumatic Stress Symptom Scale for Children; HRSD = The 17-item Hamilton Rating Scale for Depression; BDI = Beck Depression Inventory; HADS-A = the HospitalAnxiety and Depression Scale –Anxiety; HADS-D = the Hospital Anxiety and Depression Scale – Depression; MADRS = The Montgomery–Asberg Depression RatingScale; CDI = The Children’s Depression Inventory; HAMA-A = the Hospital Anxiety and Hamilton Anxiety Scale–Anxiety; HAMA-D = the Hospital Anxiety and HamiltonAnxiety Scale–Depression; CDS = Children’s Depression Scale; BAI = Beck Anxiety Inventory; STAI = State-Trait Anxiety Inventory.Intervention: AEM = automated EMD; AVA = active visual attention; IHT = image habituation training; AMR = applied muscle relaxation; REDDR = EMDR treatmentminus the eye movements; SPS = standard psychiatric support; AL = active listening; E + CR = exposure combined with cognitive restructuring; PE = prolongedexposure; SITPE = stress inoculation training with prolonged exposure; EFD = eye fixation desensitization; CBT = cognitive behavioral therapy; EFT = emotionalfreedom techniques; SC = standard care; WL = : waiting list; TTP = trauma treatment protocol; SMP = a standard stress management program.Patients/Group characterization: T/C = treatment group/control group.Cochrane tool: AA = adequacy of sequence allocation; AC = allocation concealment; BAO = blinding of assessors and outcomes; IO = incomplete outcome data; SRO= selective reporting and other biases.doi:10.1371/journal.pone.0103676.t001
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Figure 2. Overall effect size of the reduction in the symptoms of PTSD following EMDR therapy (n = 22 studies).doi:10.1371/journal.pone.0103676.g002
Figure 3. Overall effect size of the reduction in the symptoms of depression in PTSD patients following EMDR therapy (n = 20studies).doi:10.1371/journal.pone.0103676.g003
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PLOS ONE | www.plosone.org 10 August 2014 | Volume 9 | Issue 8 | e103676
addressed in most of the studies. Adequate assessments of each
outcome and adequate selective outcome reporting were per-
formed in all of the RCTs. Intention-to-treat analyses were
conducted in three studies [7,25,32]. Research-quality scores of
eight, seven, and six were determined for seven, twelve, and six
studies, respectively.
Publication Bias and Sensitivity AnalysesIn the analysis of publication bias, the funnel plot did not appear
asymmetrical, and the Egger’s regression analysis of the funnel plot
indicated that it was statistically symmetrical (data not shown),
suggesting that publication bias did not influence our results.
Sensitivity analyses were performed to assess the influence of each
individual study on the pooled effect size (Hedges’s g) based on the
systematic omission of individual studies from our meta-analysis.
Efficacy AnalysisThe effect sizes of the selected studies were significant for
symptoms of PTSD, depression, anxiety, and subjective distress.
The data revealed that EMDR group therapy resulted in
significant improvement in patients with PTSD (Table 2). The
Hedges’s g of the 22 studies that examined PTSD symptoms
following EMDR therapy was 20.662, and the 95% CI was 2
0.887 to 20.436 (Table 2; Figure 2). The effect sizes for sample
collection were all negative, with Hedges’s g ranging from 20.101
to 22.416. The meta-analysis revealed that the overall reduction
in PTSD symptoms following EMDR therapy was significant, with
a moderate effect size. Substantial heterogeneity was observed
among the studies in which PTSD symptoms were the outcomes
measured (Q = 65.062, p = 0.001, I2 = 67.723). The funnel plot for
these studies was approximately symmetrical, and the Egger’s
regression test revealed no publication bias (p = 0.98). The
sensitivity analysis indicated that the removal of any one study
did not affect the overall results.
Twenty studies that investigated depression as the primary
outcome following EMDR therapy were included in our meta-
analysis. The Hedges’s g for the overall effect size was 20.643, and
the 95% CI was 20.864 to 20.422 (Table 2, Figure 3). The effect
sizes for sample collection were all negative, with the Hedges’s granging from 20.076 to 21.995. These results suggested that the
overall reduction in depression following EMDR therapy was
significant, with a moderate effect size. Heterogeneity among the
studies of depression was moderate (Q = 42.657, p = 0.001,
I2 = 55.458). The funnel plot for these studies was approximately
symmetrical, and the Egger’s regression test revealed no publica-
tion bias (p = 0.74). The sensitivity analysis indicated that the
removal of any one study did not affect the overall results.
Sixteen studies that examined anxiety as the primary outcome
following EMDR therapy were included in our meta-analysis. The
Hedges’s g of the overall effect size was 20.640, with a 95% CI of
20.890 to 20.390 (Table 2; Figure 4). The effect sizes for sample
collection were all negative, with Hedges’s g ranging from 20.031
to 22.039. The results indicated that the overall reduction in
anxiety following EMDR therapy was significant, with a moderate
effect size. Substantial heterogeneity was observed among the
anxiety studies (Q = 46.804, p = 0.001, I2 = 67.951). The funnel
plot for these studies was approximately symmetrical, and Egger’s
regression test revealed no publication bias (p = 0.96). The
sensitivity analysis indicated that the removal of any one study
did not affect the overall results.
Twelve studies that examined subjective distress as the primary
outcome were included in our meta-analysis. The Hedges’s g for
overall effect size was 20.956, with a 95% CI of 21.388 to 2
0.525 (Table 2; Figure 5). The effect sizes for sample collection
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Meta-Analysis of EMDR
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were all negative, with Hedges’s g ranging from 20.227 to 2
2.243. These results indicated that the overall improvement in
subjective distress following EMDR therapy was significant, with a
large effect size. Heterogeneity among the studies of subjective
distress was moderate to high (Q = 47.622, p = 0.001, I2 = 76.901).
The funnel plot for these studies was approximately symmetrical,
and the Egger’s regression test revealed no publication bias
Figure 4. Overall effect size of the reduction in the symptoms of anxiety in PTSD patients following EMDR therapy (n = 16 studies).doi:10.1371/journal.pone.0103676.g004
Figure 5. Overall effect size of the reduction in the symptoms of subjective distress in PTSD patients following EMDR therapy(n = 12 studies).doi:10.1371/journal.pone.0103676.g005
Meta-Analysis of EMDR
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Meta-Analysis of EMDR
PLOS ONE | www.plosone.org 13 August 2014 | Volume 9 | Issue 8 | e103676
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Meta-Analysis of EMDR
PLOS ONE | www.plosone.org 14 August 2014 | Volume 9 | Issue 8 | e103676
(p = 0.93). The sensitivity analysis indicated that the removal of
any one study did not affect the overall results.
Subgroup Analyses of Posttraumatic-Stress Disorder,Depression, Anxiety, and Subjective Distress
The subgroup analysis of the improvement index for PTSD
symptoms revealed that the effect size for the group led by a
therapist with experience in PTSD group therapy (g = 20.753)
was significantly larger (QB = 7.195; p = 0.007) than that of the
group led by a therapist without such experience (g = 20.234;
Table 3). The subgroup analysis of the depression improvement
index indicated that the effect size of a treatment duration of .
60 min per session (g = 20.811) was significantly larger
(QB = 7.345; p = 0.007) than that of a treatment duration of #
60 min per session (g = 20.295; Table 3). The subgroup analysis
of the anxiety improvement index revealed that the effect size for a
treatment duration .60 min per session (g = 20.860) was
significantly larger (QB = 6.191; p = 0.045) than that for a
treatment duration #60 min per session (g = 20.351; Table 4).
The subgroup analysis of the subjective distress improvement
index suggested homogeneity in a majority of the studies, with only
one study remaining after stratification. Thus, heterogeneity
among the subjective distress studies did not appear to have
influenced our results (Table 4).
Meta-Regression AnalysesThe meta-analyses of the RCTs conducted to investigate the
effects of EMDR on the symptoms of PTSD, depression, anxiety,
and subjective distress in PTSD patients were performed using
unrestricted maximum-likelihood meta-regressions. No significant
relationship was observed between the effect size for PTSD and
participant age (b = 20.01, t = 20.69), publication year (b = 0.02,
t = 1.00), sample size (b = 20.01, t = 20.41), the number of
treatment sessions (b = 0.03, t = 1.02), or treatment duration
(b = 20.01, t = 21.10). No significant relationship was observed
between the effect size for depression and participant age (b = 2
0.02, t = 21.78), publication year (b = 0.01, t = 0.98), sample size
(b = 20.01, t = 20.43), number of treatment sessions (b = 20.01,
t = 20.13), or treatment duration (b = 20.01, t = 21.45). No
significant relationship was observed between the effect size for
anxiety and participant age (b = 20.01, t = 21.37), publication
year (b = 0.01, t = 0.10), sample size (b = 20.01, t = 21.35),
number of treatment sessions (b = 20.01, t = 20.10), or treatment
duration (b = 20.01, t = 21.45). No significant relationship was
observed between the effect size for subjective distress and
participant age (b = 0.03, t = 1.38), publication year (b = 20.08,
t = 21.53), sample size (b = 20.01, t = 20.81), number of treat-
ment sessions (b = 0.06, t = 0.23), or treatment duration (b = 0.01,
t = 0.34).
Discussion
Main FindingsThe objective of the current study was to perform meta-analysis
on previously reported RCTs to determine the magnitude of the
effects of EMDR therapy on the symptoms of PTSD, depression,
anxiety, and subjective distress in patients with PTSD. The meta-
analysis revealed that the effect sizes for EMDR therapy for
PTSD, depression, and anxiety were moderate, whereas the effect
size for EMDR therapy for subjective distress was large. These
results suggest that EMDR therapy can improve self-awareness in
patients, change their beliefs and behaviors, reduce anxiety and
depression, and lead to positive emotions.
PTSD patients cannot properly manage their negative experi-
ences or memories. EMDR therapy involves the use of eye
movements to induce ORs, and enables PTSD patients to create
adaptive connections to integrate negative experiences with
positive emotions and cognitions, thereby significantly improving
PTSD symptoms. Our findings were similar to those of Davidson
and Parker [3], who conducted a meta-analysis on quantitative
studies of EMDR therapy published between 1988 and 2000.
They reported a moderate effect size for EMDR therapy (r = 0.40,
Cohen’s d = 0.87), compared with that of other non-specified
therapies. Other studies have reported that EMDR therapy
produced increased reductions in PTSD symptoms, compared
with that produced by medication therapy and control groups
[6,32].
Depression is often comorbid with PTSD [33]. Twenty of the
26 studies included in our meta-analysis indicated that EMDR
therapy significantly reduced the symptoms of depression in
patients with PTSD, and our analysis revealed a moderate effect
size for EMDR therapy for depression. Our findings are consistent
with those of other studies on depression, which have demon-
strated that EMDR group therapy significantly reduced the
symptoms of depression, compared with control groups
[5,7,12,30].
Specific traumatic stressors cause PTSD patients to experience
anxiety when coping with stress. Sixteen of the 26 studies included
in our meta-analysis reported that EMDR therapy significantly
reduced anxiety in PTSD patients, and our analysis revealed a
moderate effect size for EMDR therapy for anxiety. Our findings
are consistent with those of Scheck et al. [9], who reported that
EMDR therapy significantly reduced anxiety in women with
PTSD, with a moderate effect size (Cohen’s d = 0.66). Our
findings are also consistent with those of Abbasnejad et al. [8] and
Power et al. [6], which indicated that EMDR therapy significantly
reduced the symptoms of anxiety in patients, compared with those
experienced by control patients awaiting treatment. EMDR
therapy relieves anxiety by reprocessing information when PTSD
patients undergo a subsequent traumatic event.
Patients with PTSD experience subjective distress because they
have been disturbed by previous negative experiences, and wish to
avoid the memories of those experiences. Our meta-analysis of 12
studies on the effects of EMDR therapy on subjective distress
revealed that the effect size was large. Wilson et al. [16] examined
the effects of EMDR therapy on 62 police officers who had
experienced traumatic events, and their results indicated that
EMDR therapy significantly reduced subjective distress, with a
large effect size (Cohen’s d = 2.07). Our findings are consistent
with those of a meta-analysis conducted by Davidson and Parker
in 2001 [3], which included quantitative studies related to EMDR
therapy published between 1988 and 2000. They reported that
EMDR therapy reduced subjective distress, with a large effect size
(r = 0.81, Cohen’s d = 2.71). Kemp et al. [12] also demonstrated
that, compared with a control group awaiting treatment,
subjective distress was significantly reduced in patients who had
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