EMDR and Memory – Arizona Forensic Services, LLC

Snap Shot

The question: Can eye movement desensitization and reprocessing (EMDR), a treatment for posttraumatic stress disorder, change a witness’s memory of the events that were treated, and what follows for investigations and testimony?

What the research shows: EMDR is an effective, widely recommended treatment for PTSD. In laboratory studies, recalling a memory while making eye movements reliably makes it feel less vivid and less emotional, and some studies find that it also makes details harder to retrieve. Several studies, though not all, find more spontaneous false memories after eye movements, while a larger direct replication and later reviews have not found greater susceptibility to suggested misinformation.

What it does not show: The research does not show that EMDR implants memories of events that did not happen, that a treated witness’s account is unreliable, or that any particular witness’s memory changed. Nearly all of the studies used students, video or word lists, and a few minutes of eye movements rather than a course of therapy.

The law: Expert testimony on EMDR and memory is governed by Rule 702 (as amended in 2023), Daubert, Kumho, Mil. R. Evid. 702 and 1102, and Houser, and in Arizona by Rule 702 and Chapple, Nordstrom, Lindsey, and Moran; experts explain general principles and may not opine on a particular witness’s credibility. Arizona’s rules for hypnotically refreshed testimony address hypnosis, and no published decision applying them to EMDR was located.

Issues for each side: Prosecutors and investigators can protect both treatment and evidence by recording a complete account before trauma-focused therapy begins, without delaying needed care; defense counsel can legitimately ask when treatment occurred and what the account looked like beforehand, while recognizing that the strongest findings concern vividness and emotion rather than the creation of false events.

EMDR is a structured psychotherapy for posttraumatic stress disorder (PTSD) in which a patient briefly holds a distressing memory in mind while following a therapist’s moving hand or another bilateral stimulus. It is among the most widely used trauma treatments, and complainants in sexual assault, domestic violence, and combat-related cases, as well as accused persons and other witnesses, may receive it while a case is pending. Because the treatment is designed to change how a memory is experienced, memory researchers have asked whether it can also change what is remembered.

The question reaches court when an account becomes fuller, calmer, or different after treatment, when an expert is asked whether EMDR can create false memories, and when investigators must decide whether to interview before or after therapy. This paper reviews EMDR’s effectiveness, how eye movements are thought to act on memory, the studies of accuracy and false memory, concerns about the therapeutic context, practical implications, and the governing law. The research is newer and more contested than research on hypnosis, and its findings are narrower than either side sometimes claims.

What EMDR Is and How Well It Works

EMDR was introduced by Shapiro (1989), who reported that guided eye movements while a person recalled a traumatic memory reduced distress. The modern protocol adds preparation and the selection of a target image and associated negative belief, followed by short sets of eye movements (or taps or tones) while the patient holds the target in mind.

EMDR has a substantial evidence base as a PTSD treatment. The World Health Organization (2013) included it among the psychological treatments recommended for PTSD. A 2026 meta-analysis of 65 randomized controlled trials involving 3,342 adults found that EMDR reduced PTSD symptoms at the end of treatment and that the benefit was sustained at follow-up, with immediate effects on anxiety and depression as well (Yang et al., 2026). A meta-analysis of 15 clinical trials and 11 laboratory studies found a moderate additional effect of eye movements in treatment studies (d = 0.41) and a large effect in laboratory studies (d = 0.74), particularly on ratings of vividness (Lee & Cuijpers, 2013). The forensic question is therefore not whether EMDR helps people with PTSD but whether the processes that make it effective can also affect memory reports used as evidence.

The Working-Memory Account of Eye Movements

The leading explanation of the eye-movement component is the working-memory account. Holding a vivid image in mind and tracking a moving target both draw on the limited capacity of working memory; when the two tasks compete, the image becomes less vivid and less emotional, and the memory is thought to be stored again in that blurred form (van den Hout & Engelhard, 2012). Consistent with that account, vertical eye movements and demanding tasks that involve no eye movement, such as counting, have produced effects similar to horizontal eye movements, suggesting that “bilateral” stimulation is not essential. A meta-analysis of 15 laboratory studies (942 participants) found that other demanding tasks reduced vividness and emotionality about as much as eye movements did, although eye movements had a small additional advantage for vividness (d = 0.29; Houben et al., 2020a).

Most of these studies rely on participants’ own ratings, which expectations can influence. Two lines of evidence address that concern. Giving participants correct or incorrect information about how EMDR works did not change the effects of eye movements, suggesting that expectations contribute little (Littel et al., 2017). And studies using behavioral measures have found that recall with eye movements slowed later recognition of the recalled picture (van den Hout et al., 2013) and slowed participants’ ability to discriminate a recalled stimulus from similar ones (Leer et al., 2017). For a forensic audience, that is the central point: a treatment that works by making a memory less vivid may also make some of its details harder to retrieve.

Does EMDR Increase False Memory or Suggestibility?

The forensic concern was sharpened by an experiment with 82 undergraduates who viewed a filmed car crash, made eye movements or kept their eyes still, and then read a witness narrative that contained false details; the eye-movement group later answered less accurately and reported more of the false details (Houben et al., 2018). EMDR clinician-researchers published a critical commentary on the study (Lee et al., 2019). More important, the central finding has not held up. A direct replication with 206 undergraduates found that eye movements did not increase acceptance of misinformation, reduce correct details, or reduce vividness and emotionality (van Schie & Leer, 2019). A registered replication from another laboratory tested the same question (Calvillo & Emami, 2019), and later reviews conclude that eye movements do not consistently increase misinformation susceptibility (Kenchel et al., 2022; Otgaar & Houben, 2026).

A different picture has emerged for spontaneous false memories, errors that arise from a person’s own associations rather than from information supplied by someone else. In a word-list study, eye movements during recall had no effect when memory was tested immediately, but when testing occurred 48 hours later, participants who had made eye movements recalled more correct words and also more related words that had never been presented (Houben et al., 2020b). A review that added new data to the published studies reached a mixed conclusion: eye movements showed no dependable effect on acceptance of suggested details and no evident memory benefit, but appeared to raise the rate of self-generated false memories (Kenchel et al., 2022). The most recent review by researchers who first raised the concern reached a similar, explicitly nuanced conclusion: EMDR seems to reduce the vividness and negative emotion of memories, and its eye movements appear to raise spontaneous false memories without raising susceptibility to suggestion (Otgaar & Houben, 2026).

Not every measure shows impairment. In a laboratory study, 265 healthy adults underwent a standardized social stress task and the next day received a single session of EMDR, imaginal exposure, imagery rescripting, or no intervention; one week later, recognition of details of the stressful event did not differ among the groups (Aleksic et al., 2025). The authors noted limits, including the absence of treatment-integrity checks. Taken together, the evidence points to effects on the vividness, emotionality, and accessibility of memories, and possibly on associative errors, rather than a general tendency to implant false events or to increase acceptance of what others suggest.

Beyond Eye Movements: Beliefs and Instructions in Therapy

Some concerns about EMDR involve not the eye movements but the therapeutic context. In two small surveys (12 and 41 EMDR practitioners, 35 and 24 students, and 30 researchers), majorities of practitioners (70% to 90%) endorsed the idea that traumatic memories can be repressed, as did about 90% of students and two-thirds of the researchers; the same groups also recognized that memory is fallible (Houben et al., 2021). Similar beliefs have been documented among clinicians generally (Patihis et al., 2014). Otgaar et al. (2021) argued that such beliefs, combined with instructions in one national EMDR protocol that describe memory with metaphors such as a video recording, could lead patients to treat imagery that emerges in therapy as a literal record of past events, and a later review noted reports linking EMDR to recovered memories (Otgaar & Houben, 2026). These concerns are most pertinent when therapy is used to search for events a person does not remember, and less so when EMDR targets a continuously remembered event; the surveys describe beliefs, not what any therapist did in a particular case.

Practical Implications: Documenting the Account and Interpreting Change

The most useful practical lesson does not depend on resolving the scientific disagreements. When a person who may become a witness is likely to receive EMDR or another trauma-focused treatment, a complete, recorded account obtained beforehand preserves the best evidence of what the person remembered before treatment. Such an account serves every party by showing whether later details were present before therapy. Treatment should not be withheld or delayed to suit the investigation; it is effective, and the research does not support telling witnesses to forgo it. The goal is sequencing and documentation, not avoidance.

The research also bears on how change is interpreted. A complainant who was visibly distressed in an early interview and is calm on the stand may have received effective treatment; reduced emotion is one of the intended effects of EMDR and is not, by itself, a sign that the original account was exaggerated. Conversely, reduced vividness and accessibility may make a treated witness less detailed or less certain than before, which is consistent with the laboratory findings and is not, by itself, a sign that the original account was false. New details that first appear after therapy warrant the same inquiry as new details from any source: when they first appeared, what the person had been told, and whether pre-treatment records contain them.

Limits of the Evidence

Nearly all of the memory research on EMDR uses healthy undergraduates, films or word lists, and a few minutes of eye movements, with testing hours or days later. Patients have PTSD, the targeted memory is personal and often old, treatment spans several sessions, and testimony may come years later. The effect sizes in the laboratory are modest, the key misinformation finding has not replicated, and the false-memory findings come mainly from word-list paradigms whose relationship to memory for real events is uncertain. Researchers who raised the concern and EMDR clinician-researchers who disputed it have both published in this literature. Most important, group studies cannot establish whether any particular person’s memory was changed by treatment; that question depends on comparing the person’s accounts over time against the available records and evidence.

Questions to Ask About This Research

When Houben et al. (2018) is cited for the proposition that eye movements increase false memories, counsel should ask how well the finding has held up: a direct replication with more than twice the sample did not find increased susceptibility to misinformation (van Schie & Leer, 2019), a registered replication addressed the same question (Calvillo & Emami, 2019), and the most recent review distinguishes misinformation from spontaneous false memory (Otgaar & Houben, 2026). When the 48-hour word-list finding (Houben et al., 2020b) is offered, counsel should ask whether the conclusion follows for memory of a personal assault, since the errors were related words on a list, not invented events. When the meta-analytic reduction in vividness (Houben et al., 2020a) is cited, counsel should ask whether it applies to this person, since it concerns self-rated vividness of laboratory memories. When Aleksic et al. (2025) is cited to show that EMDR does not impair memory, counsel should ask what was measured, since forced-choice recognition may be less sensitive than free recall. And when survey findings on practitioner beliefs (Houben et al., 2021) are offered, counsel should ask whether there is any evidence of what this therapist believed or did. These questions are explained in “Reading Research Claims: A Guide for Attorneys” on this site.

EMDR, Memory, and the Law

Federal and Military Standards

Expert testimony about the effects of EMDR on memory is governed by Federal Rule of Evidence 702, as amended December 1, 2023, which requires the proponent to show that it is more likely than not that the testimony rests on sufficient facts or data, reflects reliable principles and methods, and reflects a reliable application of those methods to the case. Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) and Kumho Tire Co. v. Carmichael (1999), which extended the gatekeeping obligation to all expert testimony, including testimony based on technical or other specialized knowledge, require courts to examine the research basis, and an unreplicated or contested finding is a legitimate subject of that inquiry. An expert may explain what the research shows about EMDR and memory in general; an expert may not testify that a particular witness’s memory is false or true, because credibility is for the factfinder. Rock v. Arkansas (1987), which barred per se exclusion of an accused’s own hypnotically refreshed testimony, did not address EMDR.

In courts-martial, Military Rule of Evidence 702 tracks the federal rule; under Military Rule of Evidence 1102, amendments to the Federal Rules of Evidence amend the parallel military rules 18 months after their effective date unless the President acts otherwise, so the 2023 amendment became part of the military rule in 2025 (Joint Service Committee on Military Justice, 2025), and practitioners should confirm current text. Military judges also apply the six factors of United States v. Houser (1993). Determining when a witness received EMDR, and what was discussed, may require access to treatment records; communications with psychotherapists are privileged under Military Rule of Evidence 513, subject to its exceptions and procedures, and the Court of Appeals for the Armed Forces has held that diagnoses and treatments contained in medical records are not themselves uniformly privileged under that rule (United States v. Mellette, 2022).

Arizona

Arizona Rule of Evidence 702 adopted the Daubert standard effective January 1, 2012, and was amended effective January 1, 2024, to conform to the 2023 federal amendment (Ariz. Sup. Ct. Order R-23-0004). State v. Chapple (1983), Arizona’s leading case on expert testimony about the reliability of eyewitness memory, held that excluding a qualified expert was an abuse of discretion on its facts, while leaving admission generally within the trial court’s discretion; State v. Nordstrom (2001) upheld limiting such an expert to general factors. Experts may not opine on a particular witness’s credibility (State v. Lindsey, 1986, 149 Ariz. at 475; State v. Moran, 1986). Arizona law makes hypnotically induced recall inadmissible, limiting testimony to facts demonstrably recalled and recorded before hypnosis, with safeguards against contamination (State ex rel. Collins v. Superior Court, 1982; State v. Lopez, 1994). EMDR is not hypnosis, and no published Arizona decision applying those rules to EMDR was located; the hypnosis cases nonetheless illustrate the value courts place on a recorded pre-treatment account. When a defendant seeks a victim’s privileged mental health records, in camera review is warranted on a sufficiently specific showing of a reasonable possibility that the records contain information to which the defendant is constitutionally entitled (R.S. v. Thompson, 2021, ¶ 30). Arizona’s general credibility instruction directs jurors to consider, among other factors, the quality of the witness’s memory and whether the witness was contradicted by anything the witness said or wrote before trial (RAJI (Criminal) Standard 15).

Special Issues in Legal Practice

The principles described above apply with equal force to every party in a legal proceeding. The science operates the same way regardless of who is asking the questions, and the research summarized here does not by itself favor either side. What differs between the parties is not the science but the vantage point — the particular places where these issues tend to surface, and the particular errors each party is best positioned to guard against. The two summaries below identify those recurring issues. They are offered for orientation, not as litigation strategy; in every case the controlling question is what the evidence in that case will, and will not, support, and the expert’s role is to inform the trier of fact rather than to advocate for either side.

Special Issues for Prosecutors

The research supports several propositions prosecutors can legitimately present. EMDR is an effective, widely recommended treatment for PTSD, and receiving it is not evidence that an account is unreliable. The best-replicated memory effects are reductions in vividness and emotion, which can explain why a treated complainant appears calmer or less detailed at trial than in early interviews. The finding that eye movements increase susceptibility to suggested misinformation did not hold up in a larger direct replication, and a recent laboratory study found no impairment of recognition after a single EMDR session. Prosecutors are well placed to ensure that a complete, recorded account is obtained before trauma-focused treatment begins, without asking a complainant to delay care, and that the start of treatment is documented.

The research also counsels caution. Studies finding reduced accessibility of details and more spontaneous associative errors mean that testimony that EMDR has no effect on memory goes beyond the evidence. When a significant detail first appears during or after therapy, the sequence is a fair subject for the factfinder, and the absence of a pre-treatment record weakens the ability to answer that question. Concerns about practitioners’ beliefs in repressed memory are most pertinent when therapy has been used to search for unremembered events, and prosecutors should be prepared to show, where it is so, that the treated memory was continuously remembered and reported before treatment.

Special Issues for Defense

The research supports several propositions defense counsel can legitimately present. EMDR is designed to change how a memory is experienced, and laboratory studies show reduced vividness and accessibility of details, and in some studies more spontaneous false memories, after eye movements. Memory researchers have raised concerns about therapeutic beliefs and instructions that may lead patients to treat emerging imagery as literal memory. It is legitimate to ask when a witness received EMDR, what the account was beforehand, whether details changed or first appeared afterward, and whether treatment searched for events not previously remembered, and to offer expert testimony on these general principles.

The research also counsels caution about the limits that apply to the defense. The study most often cited for increased suggestibility was not confirmed in a larger direct replication, and the research does not show that EMDR creates memories of events that did not occur. Laboratory findings may not transfer to a course of therapy for a personal trauma, and an expert cannot tell the factfinder that a particular witness’s memory was altered. A complainant’s calmer demeanor after treatment is consistent with the intended effect of therapy rather than with fabrication. The same principles apply to an accused or a defense witness who has received trauma-focused treatment.

This paper is for educational purposes only and is not legal advice. The author is a psychologist, not an attorney; summaries of law are general and must be verified against current authority or with a licensed attorney.

References

Aleksic, M., Ehring, T., Kunze, A., & Wolkenstein, L. (2025). Does treating emotional memories come at a price? Effects of single-session EMDR, imaginal exposure, and imagery rescripting on forced-choice recognition of event details in healthy adults – a laboratory study. Behaviour Research and Therapy, 195, Article 104884. https://doi.org/10.1016/j.brat.2025.104884

Calvillo, D. P., & Emami, A. S. (2019). Do lateral eye movements increase susceptibility to misinformation? A registered replication. Psychonomic Bulletin & Review, 26(6), 1905–1910. https://doi.org/10.3758/s13423-019-01641-6

Houben, S. T. L., Otgaar, H., Roelofs, J., & Merckelbach, H. (2018). Lateral eye movements increase false memory rates. Clinical Psychological Science, 6(4), 610–616. https://doi.org/10.1177/2167702618757658

Houben, S. T. L., Otgaar, H., Roelofs, J., Merckelbach, H., & Muris, P. (2020a). The effects of eye movements and alternative dual tasks on the vividness and emotionality of negative autobiographical memories: A meta-analysis of laboratory studies. Journal of Experimental Psychopathology, 11(1). https://doi.org/10.1177/2043808720907744

Houben, S. T. L., Otgaar, H., Roelofs, J., Smeets, T., & Merckelbach, H. (2020b). Increases of correct memories and spontaneous false memories due to eye movements when memories are retrieved after a time delay. Behaviour Research and Therapy, 125, Article 103546. https://doi.org/10.1016/j.brat.2019.103546

Houben, S. T. L., Otgaar, H., Roelofs, J., Wessel, I., Patihis, L., & Merckelbach, H. (2021). Eye movement desensitization and reprocessing (EMDR) practitioners’ beliefs about memory. Psychology of Consciousness: Theory, Research, and Practice, 8(3), 258–273. https://doi.org/10.1037/cns0000211

Joint Service Committee on Military Justice. (2025). Amendments to the Military Rules of Evidence since 1984 (G. E. Maggs, Ed.; 2025 ed.). https://jsc.defense.gov/Portals/99/MRE%20Amendments%202025.pdf

Kenchel, J. M., Domagalski, K., Butler, B. J., & Loftus, E. F. (2022). The messy landscape of eye movements and false memories. Memory, 30(6), 678–685. https://doi.org/10.1080/09658211.2020.1862234

Lee, C. W., & Cuijpers, P. (2013). A meta-analysis of the contribution of eye movements in processing emotional memories. Journal of Behavior Therapy and Experimental Psychiatry, 44(2), 231–239. https://doi.org/10.1016/j.jbtep.2012.11.001

Lee, C. W., de Jongh, A., & Hase, M. (2019). Lateral eye movements, EMDR, and memory changes: A critical commentary on Houben et al. (2018). Clinical Psychological Science, 7(3), 403–404. https://doi.org/10.1177/2167702619830395

Leer, A., Engelhard, I. M., Lenaert, B., Struyf, D., Vervliet, B., & Hermans, D. (2017). Eye movement during recall reduces objective memory performance: An extended replication. Behaviour Research and Therapy, 92, 94–105. https://doi.org/10.1016/j.brat.2017.03.002

Littel, M., van Schie, K., & van den Hout, M. A. (2017). Exploring expectation effects in EMDR: Does prior treatment knowledge affect the degrading effects of eye movements on memories? European Journal of Psychotraumatology, 8(Suppl. 1), Article 1328954. https://doi.org/10.1080/20008198.2017.1328954

Otgaar, H., & Houben, S. T. L. (2026). Nuances in the memory undermining effects of EMDR and imagery rescripting. Current Opinion in Psychology, 67, Article 102198. https://doi.org/10.1016/j.copsyc.2025.102198

Otgaar, H., Houben, S. T. L., Rassin, E., & Merckelbach, H. (2021). Memory and eye movement desensitization and reprocessing therapy: A potentially risky combination in the courtroom. Memory, 29(9), 1254–1262. https://doi.org/10.1080/09658211.2021.1966043

Patihis, L., Ho, L. Y., Tingen, I. W., Lilienfeld, S. O., & Loftus, E. F. (2014). Are the “memory wars” over? A scientist-practitioner gap in beliefs about repressed memory. Psychological Science, 25(2), 519–530. https://doi.org/10.1177/0956797613510718

Shapiro, F. (1989). Efficacy of the eye movement desensitization procedure in the treatment of traumatic memories. Journal of Traumatic Stress, 2(2), 199–223. https://doi.org/10.1002/jts.2490020207

van den Hout, M. A., Bartelski, N., & Engelhard, I. M. (2013). On EMDR: Eye movements during retrieval reduce subjective vividness and objective memory accessibility during future recall. Cognition and Emotion, 27(1), 177–183. https://doi.org/10.1080/02699931.2012.691087

van den Hout, M. A., & Engelhard, I. M. (2012). How does EMDR work? Journal of Experimental Psychopathology, 3(5), 724–738. https://doi.org/10.5127/jep.028212

van Schie, K., & Leer, A. (2019). Lateral eye movements do not increase false-memory rates: A failed direct-replication study. Clinical Psychological Science, 7(5), 1159–1167. https://doi.org/10.1177/2167702619859335

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Yang, H., Xiong, Z., Chen, X., Wo, Y., Tang, H., Qiao, M., Chen, Y., & Wang, Z. (2026). The immediate and follow-up effects of EMDR therapy for adults with post-traumatic stress disorder: A meta-analysis of randomized controlled trials. BMC Psychology, 14(1), Article 1373. https://doi.org/10.1186/s40359-026-05349-w

Legal Authorities

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).

Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).

R.S. v. Thompson, 251 Ariz. 111, 485 P.3d 1068 (2021).

Rock v. Arkansas, 483 U.S. 44 (1987).

State ex rel. Collins v. Superior Court, 132 Ariz. 180, 644 P.2d 1266 (1982) (supplemental opinion on rehearing at 209-10).

State v. Chapple, 135 Ariz. 281, 660 P.2d 1208 (1983).

State v. Lindsey, 149 Ariz. 472, 720 P.2d 73 (1986).

State v. Lopez, 181 Ariz. 8, 887 P.2d 538 (1994).

State v. Moran, 151 Ariz. 378, 728 P.2d 248 (1986).

State v. Nordstrom, 200 Ariz. 229, 25 P.3d 717 (2001).

United States v. Houser, 36 M.J. 392 (C.M.A. 1993).

United States v. Mellette, 82 M.J. 374 (C.A.A.F. 2022).

Fed. R. Evid. 702.

Mil. R. Evid. 513, 702, 1102.

Ariz. R. Evid. 702.

Ariz. Sup. Ct. Order R-23-0004 (amending Ariz. R. Evid. 702, effective Jan. 1, 2024).

Revised Arizona Jury Instructions (Criminal), Standard Criminal 15 (Credibility of Witnesses).

Related topics from Arizona Forensic Services: Courts-Martial