Effectiveness of prolonged exposure (PE) after implementation at a crime victim support centre

ABSTRACT

Background: Recent practice guidelines strongly recommend evidence-based psychotherapies (EBPs) as the first-line treatment for post-traumatic stress disorder (PTSD). However, previous studies found barriers to the implementation of EBPs and a relatively high dropout rate in clinical settings. After proving the efficacy of prolonged exposure (PE) in Japan [Asukai, N., Saito, A., Tsuruta, N., Kishimoto, J., & Nishikawa, T. (2010). Efficacy of exposure therapy for Japanese patients with posttraumatic stress disorder due to mixed traumatic events: A randomized controlled study. Journal of Traumatic Stress, 23(6), 744–750. https://doi.org/10.1002/jts.20589], we began implementing PE in a real-world clinical setting at the Victim Support Center of Tokyo (VSCT).

Objective: We aimed to investigate the effectiveness and benefit of PE for crime-induced PTSD among VSCT clients and what causes dropout from treatment.

Method: Of 311 adult clients who received counselling from clinical psychologists at VSCT due to violent or physical crime victimization from April 2008 through December 2019, 100 individuals received PE and participated in this study. Their PTSD symptoms were evaluated before and after treatment using the Impact of Event Scale-Revised and the Clinician-Administered PTSD Scale for DSM-IV.

Results: A total of 93 participants completed PE and seven dropped out after six sessions or less. The completers group improved in PTSD symptoms with significant score differences between pre- and post-treatment in IES-R and CAPS-IV. Participants’ symptoms did not exacerbate after treatment. Forty of 49 completers who left their workplace or college/school after victimization returned to work or study shortly after treatment. Compared to the completers, all dropout participants were women and younger. The majority were rape survivors, with significantly shorter intervals between victimization and treatment. The reasons for dropout were difficulty scheduling treatment between work/study schedules and manifestation of bipolar disorder or physical illness.

Conclusions: PE can be implemented with significant effectiveness and a low dropout rate in a real-world clinical setting if advantages in the system and policies, local organizational context, fidelity support and patient engagement are fortified.

HIGHLIGHTS

• We conducted prolonged exposure (PE) with a low dropout rate for crime-induced PTSD in a non-Western real-world practice setting.

• Patient outcomes and low dropout rate of PE for PTSD in this study may be due to advantages in the following areas: system and policies, local organizational context, fidelity support and patient engagement.

• When introducing PE for PTSD, it is important to confirm that patients can be reasonably engaged with PE, and to carefully assess the status of other psychiatric and physical illnesses.

Antecedentes: Las recientes guías de práctica clínica recomiendan fuertemente las psicoterapias basadas en la evidencia (EBPs por sus siglas en inglés) como primera línea de tratamiento para el trastorno de estrés postraumático (TEPT). Sin embargo, estudios previos encontraron barreras para la implementación de EBPs y una tasa de abandono relativamente alta en contextos clínicos. Después de demostrar la eficacia de la exposición prolongada (EP) en Japón (Asukai et al., 2010), comenzamos a implementar EP en un contexto clínico del mundo real en el Centro de Apoyo a Víctimas de Tokio (VSCT por sus siglas en inglés).

Objetivo: Nuestro objetivo fue investigar la efectividad y beneficio de la EP para el TEPT inducido por un delito entre los clientes del VSCT y las causas del abandono del tratamiento.

Método: De los 311 clientes adultos que recibieron consejería por psicólogos clínicos en el VSCT debido a una victimización por un delito violento o físico desde Abril del 2008 hasta Diciembre del 2019, 100 individuos recibieron EP y participaron en este estudio. Sus síntomas de TEPT se evaluaron antes y después del tratamiento utilizando la Escala de Impacto de Eventos revisada (IES-R) y la Escala de TEPT Administrada por el Clínico según el DSM-IV (CAPS-IV).

Resultados: Un total de 93 participantes completaron la EP y siete abandonaron después de seis o menos sesiones. El grupo que completó el tratamiento mejoró en los síntomas de TEPT con una diferencia de puntuación significativa entre el pre y post tratamiento en la IES-R y CAPS-IV. Los síntomas de los participantes no empeoraron después del tratamiento. Cuarenta de los 49 que completaron el tratamiento que habían abandonado su lugar de trabajo o la universidad/colegio tras la victimización retornaron a su trabajo o estudio poco después del tratamiento. En comparación con los que completaron, todos los participantes que abandonaron el tratamiento eran mujeres y más jóvenes. La mayoría eran sobrevivientes de violaciones, con intervalos significativamente más breves entre la victimización y el tratamiento. Las razones del abandono fueron las dificultades para programar el tratamiento entre los horarios de trabajo/estudio y la manifestación de un trastorno bipolar o enfermedad física.

Conclusiones: La EP puede implementarse con una efectividad significativa y una baja tasa de abandono en contextos clínicos del mundo real si se fortalecen las ventajas en el sistema y las políticas, el contexto organizacional local, apoyo a la lealtad y la participación del paciente.

KEYWORDS:

• Post-traumatic-stress-disorder
• evidence-based-psychotherapies
• prolonged-exposure
• implementation
• treatment-dropout
• victim-support

PALABRAS CLAVE:

• Trastorno de estrés postraumático
• psicoterapias basadas en la evidencia
• exposición prolongada
• implementación
• abandono del tratamiento
• apoyo a víctimas

1. Introduction

Recent practice guidelines strongly recommend evidence-based psychotherapies (EBPs) as the first-line treatment for posttraumatic stress disorder (PTSD) (American Psychological Association, 2017; VA/DoD Clinical Practice Guideline Working Group, 2017; Forbes et al., 2020). All these treatments are trauma-focused psychotherapies including cognitive processing therapy (CPT), cognitive therapy for PTSD, eye movement desensitization and reprocessing (EMDR) therapy and prolonged exposure (PE). There is a robust evidence base for the efficacy of EBPs for PTSD as superior to that of other treatments such as supportive counselling or pharmacotherapy. However, despite more recognition for the recommendation, most people with PTSD do not receive EBPs because of barriers in disseminating and implementing them (Forbes et al., 2020).

Hundt et al. (2020) highlight three types of barriers in treatment: practical reasons such as inability to make appointments due to work, school, or family commitments; emotional reasons such as high treatment stress; and treatment-related reasons such as lack of explanation of treatment principles or treatment being initiated without sufficient time to build a therapeutic alliance with the therapist. Riggs et al. (2020b) found that barriers to the implementation of EBPs for PTSD in clinical settings must be overcome at both the individual therapist level – to maintain therapist fidelity and enhance patient involvement in treatment – and the municipal and organizational policy levels. Municipal and organizational policies regarding EBPs will help guarantee therapists’ access to consultations and develop tools to improve patients’ acceptance of treatment, which may also be necessary to reduce dropout rates.

Another problem in clinical practices using EBPs is the high dropout rate. Bisson et al. (2013) identified greater dropout rates in trauma-focused psychotherapy groups compared with the waitlist/ treatment-as-usual (TAU) group. In a meta-analysis of 116 randomized controlled trials (RCTs) of different psychotherapies for PTSD, the dropout rate of trauma-focused psychotherapies was 18% (95% confidence interval [CI]: 15–21%), higher than 14% (95% CI: 10–18%) in non-trauma focused psychotherapies (Lewis et al., 2020). As a result of meta-analysis regarding risk factors that predict treatment dropouts, there was no significant difference in dropout rates based on the patients’ gender or type of trauma (Lewis et al., 2020). Exacerbation of symptoms during treatment was also irrelevant to dropout (Eftekhari et al., 2020). Some studies identified an age factor in patients: the younger the age, the higher the dropout rate (Garcia et al., 2011; Kehle-Forbes et al., 2016).

Previous studies showed high dropout rates of EBPs in real-world clinical settings (Eftekhari et al., 2013; Kehle-Forbes et al., 2016; Mott et al., 2014). Najavits (2015) reviewed studies and found that dropout rates of EBPs in real-world clinical settings were higher than those in RCTs. To decrease treatment dropout in a real-world clinical setting, a stronger therapeutic alliance may be required with a proper explanation of therapeutic principles, and clinicians should also receive consultation (Foa et al., 2020).

In our RCT study, we found that PE was efficacious in treating Japanese PTSD patients compared to TAU (Asukai et al., 2010). After proving the efficacy of PE in Japan, we began implementing PE at the Victim Support Center of Tokyo (VSCT), a real-world practice setting for crime-induced PTSD from April 2008.

The aim of this report is to investigate the effectiveness and benefit of PE after implementation in a real-world setting at VSCT and what causes dropout from PE.

2. Method

1. Setting

VSCT is a non-governmental organization established in 2000 under the auspices of the Tokyo Metropolitan Government and Tokyo Police Department. The objective of VSCT is to assist victims of a variety of crimes, including physical/sexual assaults, motor vehicle accidents, and bereaved family members in the wake of murders or accidents. In addition to self-referrals, victimized clients are referred by police officers, prosecutors, attorneys, clinicians, or local government officers in the Tokyo area. VSCT services consist primarily of support for effective participation in the criminal justice process, providing information that victims need, and accompanying victims to court or the prosecutors’ office. For victims who need counselling, VSCT clinical psychologists provide counselling services. They provide supportive counselling and/or trauma-focused CBT for PTSD. In addition to PE, VSCT offers trauma-focused CBT for children and a programme for bereaved families. Our RCT study of PE in Japan was completed in 2008 and it was published in 2010. VSCT started providing PE after the RCT study concluded in 2008, and since 2011, the Tokyo Metropolitan Government Support Plan for Crime Victims has featured PE as one of VSCT’s services.

The VSCT Chair (N.A.) is a psychiatrist who conducted PE studies in Japan as a local PE trainer. At VSCT, the managing director and other staff members receive a lecture on PTSD and an overview of PE to understand the positive effects of PE, clients’ suffering, and hope for recovery. All staff understand PE and can explain and recommend the recovery process to victims.

2.	Prolonged exposure therapy

PE, an exposure-based trauma-focused CBT, has been strongly recommended for the treatment of PTSD in recent practice guidelines. Research has demonstrated the efficacy of PE across a variety of populations (see Riggs et al., 2020a for review). The number of PE sessions usually range between 8 and 15 (Riggs et al., 2020a).

3.	Participants

VSCT provided psychological counselling to those who needed psychological care by clinical psychologists. A total of 311 victims aged 18 and over received psychological counselling from April 2008 to December 2019. Of these 311 victims, 100 participated in this study during this period (Table 1). We defined dropout as PE ending in six sessions or fewer regardless of symptom improvement. The rest were PE completers, who agreed with the therapist to terminate PE.

Table 1. Demographics of participants.

		All (N = 100)	PE Completers (n = 93)	PE dropout (n = 7)
Age	Mean	28.73	29.13*	23.43*
	SD	10.01	10.21	4.35
Gender	Female	94	87(94%)	7(100％)
	Male	6	6(6%)	0
Type of crime victimization	Attempted murder	8	8(9%)	0
	Traffic accident	1	1(1%)	0
	Robbery	4	4(4%)	0
	Rape	56	50(54%)	6(86％)
	Sexual assault	23	23(25%)	0
	Physical assault	7	6(6%)	1(14％)
	Others	1	1(1%)	0
Interval between victimization and starting PE (months)	Mean	28.14	29.81**	6.0**
	SD	48.76	50.18	2.38
Number of sessions	Mean	11.09	11.64	4
	SD	4.54	4.23	1.63
Profession	Office worker	51	50(54％)	1(14％)
	Self employed	7	7(8％)	0
	Part-time worker	9	9(10％)	0
	Student	21	16(17％)	5(71％)
	Unemployed	12	11(12％)	1(14％)
Educational history	Junior high school/high school dropout	2	2（2％）	0
	High school	26	26(28%)	0
	College/graduate school	61	50(59%)	6(86%)
	Unknown	11	10(11%)	1(14%)
Marital status	Married	15	13(14%)	2(29%)
	Unmarried/divorced	85	80(86%)	5(71%)
Number of participants who had psychiatric treatment	prior to victimization	22	20(22%)	2(29%)
	After victimization	72	68(73%)	4(57%)
Number of participants who had past trauma		43	41(44%)	2(29%)
Referral	Self	18	16(17%)	2(29%)
	Family/friend	5	5(5%)	0
	Police officer	52	49(53%)	3(43%)
	Prosecutor	7	7(8%)	0
	Lawyer	5	4(4%)	1(14%)
	Medical doctor/psychologist	13	12(13%)	1(14%)
Status of work/study after victimization	Maintained	35	29(31%)	6(86%)
	Retirement/leaving school	29	28(30%)	1(14%)
	Temporary retirement	21	21(34%)	0
	Unknown/unemployed	15	15(16%)	0
Number of participants who returned to work/study after completing PE			40 out of 49 who left work/study after the event.

Note: Demographics of all data (All), PE completers, and PE dropouts are shown; PE completers and PE dropouts were compared with an unpaired t-test. SD: standard deviation, *p < .05, **p < .001.

3.1	Inclusion criteria

Only the victims themselves were included. Victims’ families and bereaved family members were excluded. Clients who showed a cut-off value of 25 points or more on a self-rating scale, the Impact of Event Scale-Revised (IES-R; Weiss, 2007; Japanese version: Asukai et al., 2002) and those suspected to have PTSD symptoms in an interview with a clinical psychologist were administered the Clinician-Administered PTSD Scale for DSM-IV (CAPS-IV: Blake et al., 1995; Japanese version: Asukai et al., 2003). PE was introduced to those who met the DSM-IV PTSD diagnostic criteria or who had partial PTSD (at least one symptom in each symptom cluster: reexperiencing, avoidance/psychic numbing, and hyperarousal).

3.2.	Exclusion criteria

We excluded patients who had a history of serious mental disorders (schizophrenia, severe depression, bipolar disorder, or severe dissociation) or suicide attempts within 3 months.

4.	Therapists

Between April 2008 and December 2019, the period in which the study was conducted, the number of clinical psychologists increased from two to seven at VSCT. All were female and worked part-time. All of them completed a 4-day PE training course and received weekly consultation using session videos for the initial two PE cases. To date, four out of seven clinical psychologists have been certified as PE consultants from the Center of Treatment and Study for Anxiety, University of Pennsylvania by the developer of PE. We did not use an objective scale of fidelity; however, we had consultation meetings for all ongoing PE sessions weekly to check and ensure PE protocols were followed by the local PE trainer and PE supervisor through listening to reports on treatment records and watching recordings.

5.

Measures

We defined effectiveness as the reduction in PTSD symptoms and dropout rate, and benefit as improvement in clients’ work/college functioning.

As previously mentioned, traumatic stress symptoms were assessed using the Japanese version of IES-R and CAPS-IV. The validity and reliability of the Japanese versions of IES-R (Asukai et al., 2002) and CAPS-IV (Asukai et al., 2003) have been confirmed. IES-R scores range from 0 to 88. The cutoff value for a PTSD of partial PTSD high-risk subject on the Japanese version of IES-R is 24/25 (Asukai et al., 2002).

5.1.	Work/college functioning

We focused on clients who were unable to work/study after being victimized, then returned to work/study after PE. Clients reported whether they were at work or in school in the questionnaire before the PE started, and the therapist verbally checked their work or school status at the end of the PE.

6.	Procedure to introduce PE

Eligible clients were referred to PE after it was confirmed that they were not at a stage in the criminal justice process where it would be detrimental to start PE: for example the trial had already concluded, or confirmation had been obtained from the prosecutor that they were not likely to be asked to testify at the trial.

Clinical psychologists provided an overview of PE with video-clip comments or letters from PE completers who had recovered significantly after treatment. The clients were informed of the benefits of PE and the possible psychological distress which could occur during treatment.

The choice of treatment was based on the client's preference, and supportive counselling was continued unless PE was chosen. VSCT staff and the clinical psychologists helped clients in the criminal justice process before PE was started, so there was a positive emotional bond between the client and the clinical psychologist beforehand. Therefore, we agreed on treatment goals and therapeutic tasks in PE with the clientele based on the positive emotional bond established through our support in the criminal justice process. Participants provided written informed consent. The Ethics board of the Tokyo Metropolitan Institute of Medical Science approved this study (No. 13-14).

2.1. Data analysis

We evaluated the differences in scores of IES-R and CAPS-IV between pre- and post-treatment using paired-samples t-tests in PE completers. The effect size was also calculated. Additionally, we evaluated the differences of demographic data and pre-treatment scores of IES-R and CAPS-IV between PE completers and dropout participants using unpaired t-tests. Some participants who showed significant PTSD symptoms in the clinical interview with high IES-R scores did not undergo CAPS-IV assessment. A few participants were diagnosed with PTSD using CAPS-5 and their CAPS scores were not included in data analysis. In such cases, they were excluded from CAPS-IV analysis. SPSS ver. (28) was used for analysis.

3. Results

1.	Demographics of the participants

Among the 100 participants, 94 were women and six were men. Their mean age was 28.73 years (SD = 10.01) (age range: 16–62). Concerning the type of crime clients had experienced, rape and sexual assault were the most common, with a combined total of 79 (79%). The average interval period between criminal victimization and introduction of PE was 28.14 months (SD = 48.76), or approximately 2.5 years. The comparatively high SD indicated that the interval period varied significantly. The largest number (n = 50) were full-time company employees, and in terms of educational background, most of them (n = 61) had completed programmes in college, graduate school, or vocational school. A total of 94 participants visited clinics for psychiatric treatment. Among them, the majority (n = 72) received treatment only after victimization whereas a minority (n = 22) had a history of psychiatric treatment before victimization. Forty-three participants had a prior history of trauma before the recent victimization. Fifty participants took leave from their jobs or absence from college owing to distress and difficulties due to victimization.

2.	Treatment effects

Among 100 participants, 93 completed PE and only seven (7%) dropped out (premature termination with six sessions or fewer). Demographics of completers and dropout participants are shown in Table 1. The mean number of PE sessions was 11.64 (SD = 4.23) in the completer group, and four (SD = 1.63) in the dropout group.

All the completers showed improvement of PTSD symptoms with significant score differences between pre- and post-treatment in IES-R (n = 93, t = 18.6, d.f. = 92, p < .001, d = 1.93) and CAPS-IV (n = 82, t = 20.53, d.f. = 81, p < .001, d = 2.27) (Table 2). After completing PE, 74 of 93 (79.6%) had a score of 24 or less, the cutoff point of IES-R Japanese version; and 42 of 82 (51.2%) who completed CAPS-IV no longer met diagnostic criteria for PTSD; and 31 of 82 (37.8%) had a score of 19 or less. None of the completers showed an exacerbation of symptoms after treatment. Before treatment, 49 patients among completers left work or college after crime victimization and 40 (81.6%) returned to work or school/college after treatment.

3.	Characteristics of dropout patients

Table 2. Treatment effects in PE completers (score differences between pre- and post-treatment).

	Mean score (SD)	t-value	d.f.	p-value	Cohen’s d (95%CI)
IES-R pre (n = 93)	47.61 (15.63)	18.63	92.00	<.001	1.93 (1.59-2.28)
IES-R post (n = 93)	16.45 (13.59)
CAPS-IV pre (n = 82)	70.98 (20.07)	20.53	81.00	<.001	2.27 (1.86-2.68)
CAPS-IV post (n = 82)	26.71 (18.70)

Note: Corresponding t-tests were used in the analysis. IES-R: Impact of Event Scale-Revised; CAPS-IV: Clinician-Administered PTSD Scale; SD: standard deviation; DF: degree of freedom; CI: confidence interval.

The characteristics of dropout participants (n = 7) compared to completers (n = 93) were the following: all were women, and they were younger (mean 23.4 vs 29.1 years, p < .05); most were students (5 of 7); and rape victims (6 of 7). The interval period between victimization and treatment in dropout participants was significantly shorter than that in completers (mean 6 vs 29.8 months, p < .001). Dropout participants also showed higher subjective symptom scores at pre-treatment compared to completers (mean IES-R score = 57.6 vs 47.6, p < .05; mean CAPS-IV score = 83.0 vs 71.0, p = .127). Only a few dropout participants had a history of past trauma (n = 2).

The most frequent reason for dropping out was not having time to attend sessions because of work (n = 3) or study (n = 1) schedules. IES-R scores decreased in three of these four participants at the last observation compared to pre-treatment. The other reasons were hospital admission due to manifestation of bipolar disorder (n = 2) or suspected coronary heart disease (n = 1). IES-R scores in these three patients did not decrease at the last observation compared to pre-treatment (Table 3).

Table 3. Characteristics of dropout cases.

Case	Type of victimization	Number of sessions	IES-R score		Reason for dropout
			Pre-treatment	Last observation before dropout
1	Rape	4	54	33	Difficulty in sparing time for PE due to schedule
2	Physical assault	5	69	54	Difficulty in sparing time for PE due to schedule
3	Rape	6	54	42	Difficulty in sparing time for PE due to schedule
4	Rape	5	68	68	Difficulty in sparing time for PE due to schedule
5	Rape	1	46	46	Bipolar disorder
6	Rape	4	53	53	Bipolar disorder
7	Rape	3	59	53	Suspected physical illness

Note: IES-R: Impact of Event Scale-Revised.

4. Discussion

In this study, we administered PE to 100 Japanese clients with crime-induced PTSD in Tokyo. We found that PE, a strongly recommended evidence-based psychotherapy for PTSD, was implemented with significant effectiveness and there was a low dropout rate in a non-Western real-world clinical setting of victim support. Effect sizes between pre- and post-treatment assessed by IES-R and CAPS-IV in 93 PE completers were 1.93 and 2.27, respectively. In addition, among those who took a leave of absence from their workplace or college/school due to mental difficulties occurring following victimization, 82% (40 out of 49) of individuals were able to return to work or study shortly after completing PE. The dropout rate (7%) was quite low compared to the mean dropout rate (22%) in previous PE studies (Lewis et al., 2020) including our RCT in Japan (25%) (Asukai et al., 2010). Our findings highly encourage the use of PE in real-world clinical settings for PTSD across the world.

Younger age has been a risk factor for dropout from EBPs (Garcia et al., 2011; Kehle-Forbes et al., 2016). Our findings were consistent with these results as dropout patients (n = 7) were significantly younger than completers. However, the interval period between victimization and start of PE was also significantly shorter in dropout participants than completers (mean 6 vs 29.8 months, p < .001). The most frequent reason in dropout (n = 4) was a practical problem, that is, difficulty in sparing time to continue treatment because of their return to work or college/school. Three of these four participants partially improved in their IES-R scores at the last observation before dropout. Thus, completing treatment did not seem to be a priority for them after resuming their social activities. The other reason for dropout (n = 3) was the onset of other disorders (bipolar disorder, n = 2; physical illness, n = 1) during PE that needed to be prioritized in treatment. One of them who developed bipolar disorder was hospitalized and successfully completed PE after manic-depressive symptoms were stabilized with medication. None of the participants who had PE with a longer interval (one year or more) after trauma showed comorbidities included in the exclusion criteria. Therefore, manifestation of other disorders that need to be prioritized in treatment might be a risk factor in dropout particularly in the earlier stage after trauma. Our findings suggest that potential comorbidities may be overlooked and lead to dropout when starting PE at an earlier stage following trauma.

The effectiveness of PE that we showed in this study can be attributed to systematic and supported implementation at VSCT. We observed that the following systems and environmental arrangements may have contributed to the favourable outcome.

First, in terms of system and policies, utilization of PE for crime-induced PTSD in VSCT is included in the Tokyo Metropolitan Victim Support Plan. Patients receive free treatment, and clinical psychologist consultations and personnel fees are provided by the government. Second, from the organizational context, the VSCT Chair is a psychiatrist who conducted PE studies in Japan as a local PE trainer and VSCT staff members are positive about conducting PE. The positive effect and benefit of PE in each client is shared among staff members, enhancing trust for treatment. Therefore, they encourage clients to engage in PE before or after a PE session. The staff's understanding of PE allows the clinical psychologists to feel comfortable performing PE in the workplace. Furthermore, the benefit of offering effective treatment for PTSD at VSCT is well understood by the victim support section of the Tokyo Police Department that refers victims to VSCT. Third, in terms of fidelity support, essential for implementation of EBPs, certified PE consultants supervise PE trainees with session-to-session videos and weekly consultation meetings for ongoing PE. Regular consultation can prevent patient dropout (Foa et al., 2020). Fourth, VSCT helped clients in the criminal justice process before referring them to PE, so there was a pre-existing relationship of trust between the VSCT/clinical psychologist and the client. In addition, as described in the Methods section, clinical psychologists provided an overview of PE with video-clip comments or letters from PE completers who had recovered. These materials are extremely powerful tools for enhancing the client’s motivation to receive PE and these efforts might have contributed to building trust or relationship. The clinical psychologists assisted the client through the criminal justice process, and the experience of going through this process together contributed to building a positive emotional bond between the clinical psychologists and their clients. We emphasize the importance of explaining the treatment, therapeutic alliance, and the patient’s preference. Hundt et al. (2020) found that a lack of explanation of the treatment plan and lack of sufficient time to build a therapeutic alliance with the therapist are factors leading to dropouts. The therapeutic alliance as a collaborative relationship between the therapist and patient is influenced by the extent to which there is an agreement on treatment goals, a defined set of therapeutic tasks or processes to achieve the stated goals, and the formation of a positive emotional bond (Baier et al., 2020; Bordin, 1979, 1994 for review).

Multiple factors in clinicians, patients and organizations that function to limit the implementation of EBPs for PTSD and strategies to address and overcome barriers to implementation have been discussed (Riggs et al., 2020b). Those are approaches in systems and policies, local organizational context, fidelity support and patient engagement. Overall, implementation of PE in VSCT may be due to advantages in these four key areas.

This study has a few limitations. First, the same therapist conducted the assessment and treatment for each participant. Therefore, lack of independent assessors might result in assessment bias. However, positive results were similar both in scores of IES-R as a self-rating scale and CAPS-IV as an interviewer-rating scale. This may suggest that assessment bias was not a significant problem in this study. Second, traumatic events followed by PTSD symptoms were exclusively crime victimization and the number of individuals with complex trauma and comorbidities might not be large. However, 43% of participants had a prior history of trauma before the recent victimization. We regard our exclusion criteria as reasonable in a real-world clinical setting of PE to avoid adverse effects of trauma-focused psychotherapies. Third, we did not investigate the outcome of clients with PTSD symptoms who did not prefer PE. Those clients were rare and usually referred to mental health clinics if they requested, after having supportive trauma counselling multiple times at VSCT as part of victim support services. Considering that supportive counselling or pharmacotherapy is not efficacious for PTSD compared to EBPs, it is possible that their PTSD symptoms will linger. Fourth, we did not exclude concurrent pharmacotherapy. Therefore, the positive treatment effect might be partially attributed to medication. However, evidence showed that combined treatment with PE and pharmacotherapy was not superior to PE only. The possible effect of concurrent pharmacotherapy may be small. Fifth, the study did not use a scale to measure implementation outcomes, such as acceptability, adoption, appropriateness, feasibility, fidelity, implementation cost, penetration, and sustainability (Proctor et al., 2011; 2023). For PE to be widely adopted by victim support services in Japan, it needs to be funded by local authorities. Thus, it may be important to demonstrate implementation costs and sustainability. We would like to evaluate the acceptability, fidelity, and appropriateness of PE in VSCTs using objective scales and then calculate implementation costs to contribute to dissemination in future.

In conclusion, our findings suggest that PE is effective in real-world VSCT settings. It could have been influenced by advantages fortified in the system and policies, local organizational context, fidelity support and patient engagement. Since the availability of PE for PTSD remains extremely limited in real-world clinical settings, it is crucial to facilitate the integral approach in these areas to implement PE for PTSD, which would potentially provide immense benefit to individuals suffering from PTSD.

Acknowledgements

We would like to thank Professor Edna Foa and her colleagues from the Center for the Treatment and Study of Anxiety, at the University of Pennsylvania for supporting us to disseminate PE in Japan and Victim Support of Tokyo. We would like to thank Editage (www.editage.cn) for English language editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The data that support the findings of this study are available from Victim Support Centre of Tokyo. Restrictions apply to the availability of these data, which were used under license for this study.