Effectiveness of an intensive outpatient treatment programme combining prolonged exposure and EMDR therapy for adolescents and young adults with PTSD in a naturalistic setting

Effectiveness of an intensive outpatient treatment programme combining prolonged exposure and EMDR therapy for adolescents and young adults with PTSD in a naturalistic setting (Effectiveness of an intensive outpatient treatment programme combining prolonged exposure and EMDR therapy for adolescents and young adults with PTSD in a naturalistic setting )

 

Authors: Elvira M. Rentinck, Rosa van Mourik, Ad de Jongh & Suzy J. M. A. Matthijssen

 

Translated by: Specialist Psychologist Gizem Pozam

 

ABSTRACT

Background: Psychotherapeutic interventions aimed at treating post-traumatic stress disorder (PTSD) in adolescents and young adults are hampered by high dropout rates. Based on findings from adult treatments, brief, intensive outpatient treatment programmes may offer a promising alternative, but this has not yet been tested in this younger population.

Objective: To evaluate the outcomes of a six-day intensive outpatient trauma-focused treatment programme for young people (aged 12–25) with PTSD. The treatment combined prolonged exposure and EMDR therapy, supplemented by physical activity and the involvement of relatives and/or friends. Treatment was delivered by a rotating team of therapists.

Methods: Seventy-four adolescents and young adults with PTSD and memories of at least four Criterion A traumatic events (89% female, mean age = 18.6, 36 patients aged 12–17 and 38 patients aged 18–25; SD = 3.1) participated in the programme. PTSD symptoms, depressive symptoms and the perceived burden of trauma symptoms were assessed before treatment, at the start of treatment and one month after treatment.

Results: Patients showed a significant reduction in PTSD symptoms from pretreatment to one month after treatment (Cohen's d = 1.66). Of all patients, 52 (70%) showed a clinically significant response, and 48 (65%) no longer met the diagnostic criteria for PTSD one month after treatment. Depressive symptoms also decreased significantly (Cohen's d = 1.02). The dropout rate was 4% (N = 3). No patients experienced adverse events or symptom deterioration.

Conclusions: The results indicate that a brief, intensive outpatient treatment programme combining prolonged exposure, EMDR therapy, physical activity and the involvement of relatives and friends is well tolerated and offers an effective and safe treatment alternative for adolescents and young adults with PTSD resulting from multiple traumatic experiences.

 

 

Introduction

Trauma-focused cognitive behavioural therapy and eye movement desensitisation and reprocessing (EMDR) therapy are first-line interventions for adolescents and (young) adults with post-traumatic stress disorder (PTSD), according to current international treatment guidelines (International Society for Traumatic Stress Studies ; Bisson et al., 2019; National Institute for Health and Care Excellence , 2018). These treatments are typically delivered at a frequency of one treatment session per week and show good outcomes in reducing PTSD in adolescents and (young) adults (John Baptiste Bastien et al., 2020; Mavranezouli et al., 2020).

 

Despite their effectiveness, these treatments are associated with relatively high dropout rates in adults (18%–36%; Imel et al., 2013; Lewis et al., 2020), adolescents and young adults (Simmons et al., 2021). A meta-analysis of 42 studies on PTSD treatment in adults found that dropout rates increased as the number of weekly sessions increased (Imel et al., 2013). Since there is also evidence that higher session frequency is associated with better treatment outcomes (Gutner et al., 2016), offering treatment sessions at a higher frequency over a short period may help reduce dropout rates. Similarly, adult treatment programmes using a higher session frequency over a short period have been found to yield relatively low dropout rates (<10%) and equally effective outcomes compared with treatments delivered in a weekly session format (Ragsdale et al., 2020; Van Woudenberg et al., 2018). A systematic review of 11 studies examining intensive outpatient treatment programmes for PTSD in adults found a pooled dropout rate of 5.5% (Sciarrino et al., 2020), substantially lower than the 18–36% dropout rate for treatments delivered weekly (Imel et al., 2013; Lewis et al., 2020; Simmons et al., 2021).

 

Despite efforts to reduce dropout, another challenge remains. Not every patient benefits from existing trauma interventions. To further improve treatment effectiveness and retention, an increasing number of intensive treatment programmes for adults combine prolonged exposure (PE) therapy and EMDR therapy, sometimes supplemented with physical activity and psychoeducation (Auren et al., 2022; Matthijssen et al., 2024; Van Woudenberg et al., 2018). Based on inhibitory learning theory, prolonged exposure involves sustained, controlled exposure to traumatic memories to achieve extinction through the disconfirmation of expected harm (Craske et al., 2014; Foa et al., 2007). EMDR therapy, on the other hand, facilitates the processing of traumatic memories by taxing patients' working memory, thereby reducing the emotional intensity of the memories (De Jongh et al., 2024). Combining these evidence-based therapeutic approaches may improve the outcomes of trauma-focused therapy because of their complementary mechanisms of action (Van Minnen et al., 2020). In addition, a meta-analysis found that adding physical activity enhances the effects of PTSD treatment (Rosenbaum et al., 2015). Such combined treatment programmes for adults typically employ a therapist rotation model, in which each session is delivered by a different therapist. Evidence suggests that rotation increases therapists' treatment adherence and reduces their fear and avoidance behaviours (Van Minnen et al., 2018).

 

Although promising in adults (Matthijssen et al., 2024; Van Woudenberg et al., 2018), conclusive evidence of the effectiveness of such combined programmes in adolescents is lacking. To our knowledge, only one study has investigated the effectiveness of an intensive programme combining prolonged exposure, EMDR therapy, physical activity and psychoeducation delivered by rotating therapists for an adolescent population (Van Pelt et al., 2021). The results of this study, conducted in an inpatient setting, showed that after an average of 13 treatment days, 63% of 27 adolescents achieved diagnostic remission of PTSD (Cohen's d = 1.39), with no dropouts. Our searches of databases such as PubMed, PsycINFO, Google Scholar and ScienceDirect identified no studies evaluating intensive treatment programmes combining evidence-based therapies for adolescents in an outpatient setting. The present study elaborated on the outpatient treatment programme developed for adults by Matthijssen and colleagues (2024). Using a therapist rotation model, this programme combines prolonged exposure and EMDR therapy, supplemented by physical activity and the involvement of the patient's support network, such as relatives and friends. In our clinical experience, we have observed that patients' close contacts play a positive role in providing support and motivation.

 

The aim of this study was to determine the effectiveness and dropout rate of an intensive outpatient treatment programme for adolescents and young adults experiencing PTSD resulting from multiple traumatic experiences. It was hypothesised that treatment would be associated with significant reductions in (1) PTSD symptom severity, (2) the number of patients meeting the diagnostic criteria for PTSD, (3) the perceived burden of trauma symptoms across various areas of life and (4) depressive symptom severity. In addition, it was hypothesised that the intervention would be associated with a low dropout rate (<10%) and that no adverse events would occur.

 

Method

Participants

Participants were referred to the intensive outpatient trauma treatment programme at GGZ Noord-Holland-Noord, a mental health organisation in the Netherlands. This organisation specialises in services addressing a range of mental health problems in children, adolescents and (young) adults. Of 80 consecutive referrals eligible for participation, 77 agreed to participate and 74 consented to the use of their data in our study. Accordingly, the sample included 74 individuals aged 12–25 (mean age = 18.6 years; 36 patients aged 12–17 and 38 patients aged 18–25; SD = 3.1). Participants were eligible for the study if they had previously been exposed to four different traumatic events meeting Criterion A for PTSD. These events could involve different perpetrators, different types of trauma or different events meeting Criterion A involving the same perpetrator. Establishing four traumatic events as an eligibility criterion helped ensure that the programme focused on individuals likely to have more severe and comorbid symptoms. In this respect, it may help improve generalisability to a broader population of patients suffering from severe and complex PTSD because of complex trauma histories. Participants also had to meet the diagnostic criteria for PTSD according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM; American Psychiatric Association, 2013). Patients were treated between March 2021 and January 2023.

 

Procedure

The treatment programme was evaluated in accordance with the research principles set out in the Declaration of Helsinki and the Dutch Medical Research Involving Human Subjects Act governing scientific research (World Medical Association, 2001). Because routine outcome monitoring data from the treatment programme were used for analysis, no random allocation took place and no additional intrusion on the individual was anticipated, the Medical Research Involving Human Subjects Act (WMO) did not apply. Only patients who met the inclusion criteria and provided written consent for the anonymous use of their data (with parental consent where necessary) were included in the data analyses.

 

 

Patients were referred by their therapists or general practitioners from various regions of the Netherlands. Following referral, independent assessors checked the inclusion criteria using the Life Events Checklist for DSM-5 (LEC-5; Boeschoten et al., 2014) and the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5; Boeschoten et al., 2018). Comorbid diagnoses were obtained from referrers, who were asked to document the patient's current comorbid diagnoses in the referral letter. Patients completed two self-report questionnaires: the Children's Revised Impact of Event Scale (CRIES-13; Verlinden & Lindauer, 2017) and the Beck Depression Inventory (BDIII; Beck et al., 1996). They also completed six additional items concerning the perceived burden of trauma symptoms across various areas of life. No other trauma treatment was provided following inclusion and the initial assessment. The referrer remained involved to support the patient and, if necessary, resume treatment after the intensive trauma treatment programme. Following this assessment, a treatment plan was developed in collaboration with the patient, the referrer and the patient's close contacts. The patient's trauma history was used to develop a case conceptualisation, with memories listed in order, beginning with the most distressing memory. The self-report questionnaires were administered again at the beginning of the first treatment day and one month after the end of treatment. One month after treatment, independent assessors administered the CAPS-5 again. Therapists monitored potential adverse events, such as suicide attempts and serious self-harm, from the initial assessment until one month after treatment. Five weeks after treatment completion, a treatment evaluation meeting was held with the patient, the patient's close contacts, referrers and therapists.

 

Treatment

The intensive trauma treatment programme consisted of six treatment days, divided into three treatment days per week over two consecutive weeks. Each day followed the same structure to facilitate the processing of traumatic memories using both prolonged exposure (PE) and EMDR therapy. At least one traumatic memory was addressed each day, beginning with PE and, after a short break, followed by EMDR therapy targeting the same memory.

Daily Structure:

1. 90 minutes of prolonged exposure (PE).


2. 15-minute break.


3. 90 minutes of EMDR therapy.


4. Brief meeting with the patient and their close contacts.


5. Lunch with the patient and their close contacts.


6. Physical activity guided by a (psychomotor) therapist leading different types of sports.

Even if the memory had not been fully processed by the end of the day, the next traumatic memory in the treatment schedule became the focus of treatment the following day. Therapists rotated daily, and patients received treatment from 3–5 therapists. At the end of each treatment day, therapists documented progress in the patient's treatment record. All therapists held a master's degree in clinical psychology and were trained in prolonged exposure and EMDR therapy. Therapists were instructed to follow the printed protocols precisely when delivering the therapies. Sessions were occasionally supervised to prevent protocol drift. In addition, supervisors attended weekly multidisciplinary meetings to ensure adherence to the protocols. Patients' close contacts attended one or two meetings with a family therapist each week. To increase understanding and support among patients' close contacts, the family therapist offered them support and provided psychoeducation about PTSD and the treatment programme.

 

Exposure

For prolonged exposure, the Dutch protocol by Van Minnen and Arntz (2017), based on Foa and colleagues (2007), was used. Patients were exposed to the trauma by imagining a traumatic memory as vividly as possible and describing sensory details aloud, in the present tense and first person, with their eyes closed, for 90 minutes per session. Hotspots (the most distressing parts of the traumatic memory) were repeated several times during the session. Where useful, in vivo materials collected by therapists and patients based on the case conceptualisation were used to cue trauma memories and facilitate deepened extinction. This technique involves combining multiple fear-provoking stimuli to enhance inhibitory learning and improve long-term retrieval (Craske et al., 2014). Because of the programme's intensity, patients were not assigned homework but were encouraged to practise with the in vivo materials.

 

EMDR therapy

EMDR therapy was delivered for 90 minutes per session according to the standard EMDR protocol for patients aged 18 and over (De Jongh and Ten Broeke, 2019) or the standard EMDR protocol for children and adolescents up to age 18 (De Roos et al., 2020). In cases of anticipatory fear and avoidance behaviour, patients' most frightening imagined future scenarios were desensitised using the 'flashforward protocol' (Logie & De Jongh, 2014). In accordance with EMDR 2.0, a variety of tasks, such as eye movements, cognitive tasks, cycling on a stationary exercise bike and boxing, were used to maximise the load on patients' working memory while recalling the traumatic memory (see Matthijssen et al., 2021). Cognitive interweaves (Shapiro, 2007) were used during EMDR therapy when considered necessary.

 

Materials

CAPS-5 NL

The primary outcome measures were (1) meeting the diagnostic criteria for PTSD and (2) PTSD symptom severity. Both were measured using the Dutch version of the CAPS-5 for DSM-5 (Boeschoten et al., 2018). The CAPS-5 NL has good psychometric properties (Cronbach's α: 0.62–0.83 , ICC for inter-rater reliability: 0.97–0.99) (Boeschoten et al., 2018). Each of the 20 criteria included in DSM-5 is rated on a severity scale (0–4) based on its occurrence over the past month. The total score can reach 80. An item severity score of ≥2 indicates that a specific PTSD criterion according to DSM-5 has been met.

 

CRIES-13

The CRIES-13 (Verlinden & Lindauer, 2017) is a self-report questionnaire consisting of 13 questions screening for PTSD symptoms. Each item is rated on a 4-point scale: 0 (not at all), 1 (rarely), 3 (sometimes) and 5 (often), yielding a maximum total score of 65. The CRIES is considered reliable and valid, with high internal consistency (Cronbach's alpha: 0.9; [the sample's Cronbach's alpha was 0.7], Verlinden et al., 2014).

 

BDI-II

Depressive symptom severity was assessed using the Beck Depression Inventory (BDI-II) (Beck et al., 1996). This self-report questionnaire consists of 21 items. Each item is rated on a 4-point scale (range 0–3). The total score can reach 63. The BDI-II is considered reliable and valid, with high internal consistency (Cronbach's alpha: 0.9; [Cronbach's α was 0.9 in our sample], Wang & Gorenstein, 2013).

 

Items indexing the perceived burden of PTSD symptoms on daily life

Matthijssen and colleagues (2024) formulated a separate item to assess the impact of trauma symptoms on daily life using the question, “To what extent are you currently experiencing problems in your daily life because of your trauma symptoms?” For the present treatment programme, we adopted this item using a response scale ranging from 0 ('not at all') to 10 ('maximum'), with half-point scores permitted, and added five further items to index the perceived burden of patients' trauma symptoms across various areas of daily life, worded as follows: 'To what extent do your trauma symptoms currently interfere with (I) school / studies / work, II) functioning at home, (III) friends / relationships, (IV) social time and (V) sexuality?' For these items, patients were asked to indicate the extent to which their trauma symptoms interfered with their lives on a scale from 0–10 (0 = 'no interference', 10 = 'maximum interference').

 

Data analyses

Data analyses were conducted using IBM SPSS version 27. All data were screened for data entry errors and outliers, and the extent of missing data was assessed. Expectation-maximisation (EM) algorithm imputation was performed for missing data in the self-report questionnaires and the separate items indexing the impact of patients' trauma symptoms on daily life. This algorithm generates values while preserving the relationship between a variable and other variables. Less than five per cent of the self-report data and separate items were missing. Analyses using imputed and non-imputed data showed no significant changes in descriptive statistics across measurement time points. Four patients were missing one or two CAPS5 NL measurements and were therefore excluded from the analysis. Normality assumptions were then checked. Characteristics were described by calculating frequency distributions, means and standard deviations for demographic and baseline clinical variables. To determine whether patients experienced reliable symptom improvement on the CAPS-5, the reliable change index (RCI) was calculated according to the formula by Jacobson and Truax (1991). The standard deviation and Cronbach's α (internal consistency) of the pretreatment CAPS-5 data were used to determine the RCI for this sample. Paired-samples t-tests were conducted to assess differences between pretreatment and post-treatment total scores on the CAPS-5, CRIES-13, BDI-II and additional items. In addition, paired-samples t-tests were used to analyse differences in total scores on the CRIES-13, BDI-II and additional items between pretreatment and the measurement immediately before the first session on the first treatment day. To further investigate the CAPS-5 results, exploratory analyses were conducted on the total severity scores of the different CAPS-5 domains using paired-samples t-tests. Within-subject effect sizes were calculated using Cohen's d.

 

Results

Sample characteristics Table 1 presents the sample characteristics of the 74 consecutive participants. Three patients (4%) left early because of COVID-19 (N = 1) or unwillingness to continue (N = 2).

 

Treatment outcomes

CAPS-5

Mean CAPS-5 total scores at pretreatment and one month after treatment are presented in Table 2 and Figure 1. These results showed a significant reduction in PTSD symptom severity over time, with a large effect size (t(69) = 13.85, p < .001; Cohen's d = 1.66). All CAPS-5 domains showed reductions from screening to the one-month follow-up: intrusion severity (t(1, 69) = 13.01, p < .001; Cohen's d = 1.56), avoidance (t(1, 69) = 12.62, p < . 001; Cohen's d = 1.51), negative alterations in cognition and mood (t(1, 69) = 12.19, p < .001; Cohen's d = 1.46) and alterations in arousal and reactivity (t(1, 69) = 9.38, p < .001; Cohen's d = 1.12). The internal consistency of the pretreatment CAPS-5 total score was acceptable (Cronbach's α = .75), and the reliable change index (RCI) was 14.32. More than 70% of patients (N = 52) showed significant reliable symptom improvement from pretreatment to one month after treatment, and no patients showed symptom deterioration. Of all patients, 65% (N = 48) no longer met the diagnostic criteria for PTSD one month after treatment completion.

 

 

Self-report questionnaires All mean total scores at pretreatment and one month after treatment are presented in Table 2. Self-reported PTSD symptom severity and depressive symptom severity both showed a significant decrease from pretreatment to one month after treatment, with a large effect size (t(74) = 12.25, p < .001; Cohen's d = 1.42). Analyses showed no significant reduction from pretreatment to the first treatment day in PTSD symptom severity (t(73) = -1.42, p = .16) or depressive symptom severity (t(73) = .36, p < .72). In addition, the perceived burden of PTSD symptoms across various areas of life decreased significantly from pretreatment to one month after treatment. None of these outcomes showed a significant reduction from pretreatment to the first treatment day.

Adverse effects

According to therapists' reports, none of the patients showed an increase in risky behaviours, such as self-harm or suicide attempts, and none experienced symptom deterioration.

 

Discussion

To our knowledge, this is the first study to evaluate the effectiveness of a six-day intensive outpatient trauma treatment programme for adolescents and young adults combining prolonged exposure and EMDR therapy delivered by rotating therapists. Our results indicate clinically significant improvement in 70% of patients with PTSD resulting from multiple traumatic experiences, with 65% of patients no longer meeting the diagnostic criteria for PTSD one month after treatment.

Our findings are consistent with Dancu and Foa's (1992, 2007) Emotional Processing Theory (EPT) and the theoretical foundations of EMDR therapy (Shapiro, 2018). EPT proposes that successful treatment requires activation of the fear structure and integration of corrective information. In contrast, EMDR therapy, based on the Adaptive Information Processing (AIP) model, proposes that PTSD symptoms arise from inadequately processed and maladaptively stored traumatic memories. EMDR aims to transform distressing memories by facilitating the brain's natural processing. Although the data appear to support both theoretical frameworks, greater specificity is needed to clarify how the findings support these models. In addition, because both interventions were delivered within a single programme, it is difficult to establish which specific procedures contributed to the observed effects and through which mechanisms these effects were achieved.

Our findings are also consistent with studies on the effectiveness of other intensive treatment programmes for adults, delivered in both outpatient and inpatient settings, that combine two evidence-based therapies using a therapist rotation model (Auren et al., 2022; Matthijssen et al., 2024; Van Woudenberg et al., 2018). The outcomes of our outpatient treatment programme also support findings from a residential programme for adolescents combining two evidence-based therapies delivered by rotating therapists (Van Pelt et al., 2021). Overall, our results support the idea that an intensive outpatient trauma treatment programme may be effective in treating PTSD in adolescents and young adults.

In our treatment sample, patients reported a reduced burden of PTSD symptoms across various areas of their lives, similar to findings from adult interventions (Auren et al., 2022; Matthijssen et al., 2024). In addition, comorbid depressive symptoms decreased significantly, consistent with studies in both adult and adolescent populations (Auren et al., 2022; Hendriks et al., 2017; Matthijssen et al., 2024).

In addition to faster recovery from PTSD symptoms, an important reason for offering trauma treatment in an intensive programme is to reduce dropout. The dropout rate in our study was 4% (comparable to the average dropout rate of 5.5% reported in similar intensive adult protocols; Sciarrino et al., 2020), substantially lower than the average dropout rate of 18–36% in regular treatments delivered weekly (Imel et al., 2013; Lewis et al., 2020; Simmons et al., 2021). The low dropout rate in our intensive treatment programme may be attributable to the high session frequency over a short period (Ragsdale et al., 2020; Sciarrino et al., 2020) and the clear treatment endpoint after six days.

We observed no adverse events or significant symptom deterioration from the first treatment day to the final follow-up, consistent with previous studies (Hendriks et al., 2017; Van Pelt et al., 2021). The low dropout rate, together with the absence of adverse events or symptom deterioration, suggests that adolescents and young adults can tolerate high-frequency treatment sessions delivered by rotating therapists in an outpatient setting.

The findings of this study and other studies using a therapist rotation model support the idea that a one-to-one, long-term therapeutic alliance is not always necessary. In our clinical practice, we have observed that different therapists and patients do not need to spend time establishing such an alliance, at least when the therapist acts competently. Therapists begin prolonged exposure five minutes after meeting the patient. It has been suggested that this is possible because patients develop a therapeutic alliance with the programme and the team as a whole, based on their confidence in the programme's effectiveness rather than in the therapist. For discussion and evidence suggesting that therapist rotation increases treatment adherence and reduces therapists' fear and avoidance behaviours, see Van Minnen and colleagues (2018).

 

The findings of this study should be interpreted in light of several limitations. First, the absence of a control condition limits direct comparisons with independent group-based studies. Nevertheless, our findings can be contextualised within the broader literature on intensive trauma-focused interventions. While our study relies on pre- and post-treatment comparisons to demonstrate significant improvements, the large effect sizes and substantial symptom improvement indicate that our intensive outpatient therapy effectively reduces PTSD and depressive symptoms. Furthermore, no additional trauma treatment was offered from referral until one month after treatment. Therefore, it seems unlikely that time or other non-specific factors (fully) explain our findings. In addition, high internal consistency and a substantial reliable change index support the robustness of the findings. The majority of patients no longer met the diagnostic criteria for PTSD one month after treatment, consistent with findings from controlled studies, suggesting that our approach holds considerable promise. Second, we cannot rule out the possibility of symptom deterioration after the one-month post-treatment assessment. However, other studies on PTSD symptoms in adolescents and adults have shown that treatment effects remain stable over time (Matthijssen et al., 2024; Van Pelt et al., 2021). Third, most of the study sample were assigned female at birth (89.1%), which may limit generalisability beyond female individuals. However, several studies have shown comparable trauma treatment outcomes in males and females (Danzi & La Greca, 2021; De Roos et al., 2021). Finally, independent assessors were not blinded to the timing of the patient assessment, which may have led to a positive rating bias in assessments after treatment completion.

An important strength of this study was its relatively large sample of adolescents and young adults exposed to a wide range of traumatic events and with high rates of comorbidity, increasing the external validity of the results. Another strength was the use of both standardised self-report questionnaires and a reliable and valid clinician-administered interview (CAPS - 5) to assess effectiveness. Additional strengths include the use of written protocols and the presence of supervisors at multidisciplinary meetings to optimise treatment adherence.

 

Future studies should provide a better understanding of the factors contributing to treatment success. A small subsample of patients in our study (N = 18) did not show a clinically significant reduction in symptoms. It remains unclear which factors contributed to this lack of treatment response. Potential (severe) comorbidity, fluctuating motivation and potential anxiety caused by the idea of losing PTSD symptoms may have contributed to the lack of treatment success and should be investigated in future research.

Although programmes combining two evidence-based therapies emerged from the hypothesis that different mechanisms of action may reinforce one another (Van Minnen et al., 2020), this hypothesis requires further investigation. Our study was not designed to examine the individual contributions of different treatment components to changes in symptoms. Future research should compare an intensive treatment programme using one evidence-based therapy with a programme combining therapies to distinguish the specific contributions of the different treatment components. In addition, a randomised controlled trial is needed to compare the effectiveness of an intensive programme with that of a less frequently delivered treatment.

In conclusion, the present results suggest that a six-day intensive outpatient trauma treatment programme combining prolonged exposure, EMDR therapy, physical activity and support network involvement may be effective and safe for adolescents and young adults with PTSD resulting from multiple traumatic experiences. For adolescents and young adults with PTSD, the opportunity to participate in a treatment programme with high retention rates and rapid improvement may be invaluable at a time in their lives when they need to achieve important developmental goals.

Acknowledgements

The authors thank Ellen Bockting and Lynn van Riel for their research assistance, all participants, therapists, Eva Velthorst and everyone else who contributed to this study.

Disclosure statement

Suzy Matthijssen receives income from training postgraduate professionals in EMDR 2.0 and teaching about trauma-related disorders and (intensive) trauma treatment. Ad de Jongh receives income from training postgraduate professionals in EMDR, EMDR 2.0 and teaching about trauma-related disorders and (intensive) trauma treatment. The other authors have no conflicts of interest to disclose.

Data availability statement

The data supporting the findings of this study are available from the corresponding author upon reasonable request.