Feasibility of a Web-based Single-session Intervention Combined With Ecological Momentary Assessment and Intervention for Patients With Complex Posttraumatic Stress Disorder Awaiting Inpatient Treatment

Participants complete 2 weeks of EMA, followed by the self-guided AWARE OUT intervention, 2 weeks of personalized EMA/EMI via the While Waiting Application, and a final 2 weeks of EMA. The While Waiting Application is implemented within the m-Path application.

A 30-40-minute self-guided digital intervention targeting PTSD-related difficulties and transdiagnostic processes. It provides psychoeducation and brief exercises targeting avoidance, worry, rumination, and rigid attention. Exercises include behavioral activation, postponement of worry and rumination, and attentional shifting. The intervention is delivered through videos, text, examples, and written tasks.

• SSI
• AWARE OUT

A mobile-based program comprising brief ecological momentary assessments completed 4 times daily and personalized, in-the-moment intervention prompts. Prompts support skills such as attention shifting, postponing worry/rumination, behavioral activation, challenging avoidance, and physiological regulation.

• EMA
• EMI
• m-Path
• Mens-du-venter appen

Number of eligible patients, patients invited, participants providing informed consent, participants enrolled, dropouts, and withdrawals.

Invitation is defined as receipt of a study invitation from study administrators.

Consent is defined as submission of the consent form in Nettskjema.no. Enrollment is defined as initiation of m-Path interactions.

Dropout is defined as not initiating the SSI, not completing any EMA prompts in study weeks 3 or 4, and being unreachable for clarification.

Withdrawal is defined as communicating a wish to discontinue participation.

Recruitment rate is calculated as the number of enrolled participants divided by the number of eligible patients invited to participate. Value ranges from 0 to 1; higher values indicate higher recruitment rate.

Consent rate is calculated as the number of eligible invited patients who provide informed consent divided by the number of eligible patients invited to participate. Value ranges from 0 to 1; higher values indicate greater consent uptake.

Consent-to-enrollment conversion rate is calculated as the number of enrolled participants divided by the number of participants who provide informed consent. Values range from 0 to 1; higher values indicate greater consent-to-enrollment conversion rate.

Dropout rate will be calculated as the number of dropouts divided by the number of enrolled participants.

SSI engagement will be measured as the proportion of the SSI completed by each participant, calculated as the number of intervention web pages submitted by the participant through the Nettskjema.no portal divided by the total number of intervention pages (24). Values range from 0 to 1, where 0 indicates no pages completed and 1 indicates completion of all 24 pages. SSI completion will additionally be summarized as mean completion proportion across participants. Time spent completing the SSI will also be summarized where available.

EMA adherence is measured as the proportion between number of completed EMA prompts and the number of scheduled and successfully delivered EMA prompts. Values range from 0 to 1, where higher values indicate greater EMA adherence. Participant-level and mean-level EMA adherence will be calculated. Time spent completing EMA prompts will also be summarized descriptively, where available.

EMA missing-data proportion will be calculated as 1-EMA adherence.

Engagement with EMI recommendations is calculated as the number of delivered EMI recommendations for which the participant completes at least one recommended EMI activity divided by the number of delivered EMI recommendations. Values range from 0 to 1, where higher values indicate greater engagement with EMI recommendations. Participant-level and mean-level EMI engagement with recommendations will be calculated.

Supplementary descriptive usage metrics will include the number of EMI recommendations delivered, intervention activities initiated and completed, and time spent completing intervention components, where available.

Proportion of enrolled participants who complete at least one EMA response during week 6. Values range from 0 to 1 with higher values indicate greater retention through the EMA period.

Number and nature of adverse events and unexpected circumstances. Participants have the opportunity to report events to the study administrators, and these will be summarized qualitatively. Evaluation of this measure is descriptive.

Participant-rated ease of using the While Waiting application. Assessed with one study-specific item inspired by Bringmann et al. (2025): "How easy is it to use the While Waiting application?"

The item is rated from 1 ("very difficult") to 10 ("very easy"). Higher scores indicate greater perceived ease of use.

Participant-rated positive emotional impact of answering EMA questions in the While Waiting application, assessed with one study-specific item inspired by Bringmann et al. (2025): "To what extent are your emotions positively affected by answering questions in the While Waiting application?"

The item is rated from 1 ("not affected at all") to 10 ("very affected"). Higher scores indicate greater perceived positive emotional impact.

Participant-rated negative emotional impact of answering questions in the While Waiting application, assessed with one study-specific item inspired by Bringmann et al. (2025): "To what extent are your emotions negatively affected by answering questions in the While Waiting application?"

The item is rated from 1 ("not affected at all") to 10 ("very affected"). Scores will be reverse-coded such that higher scores indicate less perceived negative emotional impact.

Participant-rated burden associated with the number of questions in the While Waiting application, assessed with one study-specific item inspired by Bringmann et al. (2025): "How burdensome is the number of questions in the While Waiting application?"

The item is rated from 1 ("not burdensome") to 10 ("very burdensome"). Scores will be reverse-coded such that higher scores indicate lower perceived burden.

Participant-rated feedback and engagement with the SSI, assessed using the 7 quantitative items from the Program Feedback Scale (PFS; Schleider et al., 2019). Items assess willingness to recommend the SSI, agreement with its message, perceived helpfulness for peers, effort during the SSI, understanding of the SSI, ease of use, and enjoyment.

Each item is rated on a 1-5 Likert scale. The outcome will be the mean score across the seven selected PFS items, ranging from 1 to 5. Higher scores indicate more favorable feedback and engagement.

Participant-rated perceived appropriateness of the SSI, assessed using two selected items from the Intervention Appropriateness Measure (IAM; Weiner et al., 2017): "AWARE OUT seems applicable" and "AWARE OUT seems like a good match."

Each item is rated on a 1-5 Likert scale. The outcome will be the mean score across the two selected items, ranging from 1 to 5. Higher scores indicate greater perceived appropriateness of the SSI.

Participant confidence that the SSI will help them with their psychological challenges and troubles. Assessed using one item from the Treatment Credibility Questionnaire (TCQ; Borkovec & Nau, 1972): "How confident are you that AWARE OUT will help you with your psychological challenges and troubles?"

The item is rated on a 1-10 scale. Higher scores indicate greater perceived treatment credibility.

Participant-rated intention to use the SSI, assessed using one item from the System Usability Scale (SUS; Lewis, 2018): "I think that I would use what I learnt in AWARE OUT going forward."

The item is rated on a 1-5 Likert scale. Higher scores indicate greater intention or willingness to use the SSI frequently.

Participant-rated negative effects of the SSI, assessed using the study-developed item: "Completing AWARE OUT has affected me negatively."

The item is rated on a 1-5 Likert scale. The item will be reverse-coded so that higher scores indicate fewer perceived negative effects.

Participant-rated perceived novelty of the SSI, assessed using the study-developed item: "I learned something new through AWARE OUT."

The item is rated on a 1-5 Likert scale. Higher scores indicate greater perceived novelty or learning.

Participant-rated appropriateness of SSI length, assessed using the study-developed item: "On a scale from 1 (far too short) to 10 (far too long), where 5 is just right, what do you think about the length of AWARE OUT?"

The item is rated from 1 to 10, with 5 indicating the most appropriate length. The outcome will be the absolute deviation from 5: absolute value of (participant length rating-5).

Scores range from 0 to 5. Lower scores indicate that the participant perceived the SSI length as closer to "just right"; a score of 0 indicates a rating of exactly 5.

Two multiple choice questions regarding which exercise they prefer, and which they least prefer. There are three exercises in the SSI, meaning they have to chose one out of the three as their preferred / least preferred choice in each question

Participant-rated usability and quality of the While Waiting application, assessed using 8 selected items from the User Version of the Mobile Application Rating Scale (uMARS; Stoyanov et al., 2016). Items assess engagement/interest (1 item), functionality (2 items: ease of use and navigation), aesthetics (2 items: layout and visual appeal), and information quality (3 items: quality, quantity, and visual presentation of information).

Each item is rated on a 1-5 scale. The outcome will be the mean score across the eight selected items, ranging from 1 to 5. Higher scores indicate more favorable perceived application usability and quality.

Participant-rated perceived impact of the While Waiting application, assessed using 5 app-specific questions adapted from the User Version of the Mobile Application Rating Scale (uMARS; Stoyanov et al., 2016). Items assess whether use of the application increased participants' awareness of, knowledge about, attitudes toward, intention or motivation to address, and anticipated behavior change related to the target health behavior.

Each item is rated on a 1-5 Likert scale. The outcome will be the mean score across the five items, ranging from 1 to 5; higher scores indicate greater perceived positive impact of the application.

Participant-rated feedback on the While Waiting application will be assessed using four selected items from the Program Feedback Scale (PFS; Schleider et al., 2019). The items assess perceived helpfulness for others having same difficulties, willingness to recommend the app to someone they know experiencing a difficult time, enjoyment of the app, and perceived ease of use.

Each item is rated on a 1-5 Likert scale. The primary outcome will be the mean score across the four selected items, ranging from 1 to 5. Higher scores indicate more favorable feedback, including greater perceived helpfulness, recommendation, enjoyment, and ease of use.

Participant confidence that the While waiting application will help them with their problems. Assessed with one item from the Treatment Credibility Questionnaire (TCQ; Borkovec & Nau, 1972): "How confident are you that the While Waiting application will help you with your psychological challenges and troubles?"

The item is scored on a 1-10 scale. Higher scores indicate greater perceived treatment credibility.

Participant feedback on study participation and answering questions in the While Waiting application will be assessed at 6 weeks after enrollment using five study-specific items adapted from Bringmann et al. (2025). Three items assess perceived burden, positive emotions, and negative emotions associated with answering questions in the application. One item assesses how positive it was to participate in the project, and one item assesses perceived burden of participating in the project.

All items are rated on a 1-10 scale. Negatively worded items will be reverse-coded so that higher scores consistently indicate a more positive participant experience (i.e., greater positive emotions/experience and lower perceived burden and negative emotions). The outcome will be the mean score across the five recoded items, ranging from 1 to 10. Higher scores indicate a more positive overall participant experience, including greater positive emotions and lower perceived burden and negative emotions

PTSD symptom severity assessed using the PTSD Checklist for DSM-5 (PCL-5, Weathers et al., 2013). The PCL-5 is a 20-item questionnaire that measures DSM-5-specified symptoms of PTSD. The total score ranges from 0 to 80, with higher scores indicating more severe symptoms. Items are rated on a 0 ('not at all') to 4 ('extremely') Likert-type scale. A Norwegian version of the PCL-5 is used in the current study (Heir, T., 2014).

Combined depression and anxiety symptom severity assessed using the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS; Kroenke et al., 2016). PHQ-ADS consists of 16 questions and scores can range from 0 to 48 (with higher scores indicating more severe depression/anxiety). Respondents are asked how much each symptom has bothered them over the past 2 weeks, with response options of "not at all", "several days", "more than half the days", and "nearly every day", scored as 0, 1, 2, and 3, respectively. A Norwegian version of the PHQ-ADS is used in the current study (Johnson et al., 2019; Wisting et al., 2021).

Open ended feedback of the While waiting application will be measured using four items focusing on 1) what the participant liked, 2) what they wish was different, 3) what was most helpful and 4) what they disliked about the application.

Open ended feedback of the SSI will be measured using three items focusing on what the participant liked, what they wish was different and what they disliked about the intervention.

Open ended feedback of the While waiting application will be measured using three items focusing on what the participant liked, what they wish was different and what they disliked about the application overall.