Study on a Digital Ultra-Brief Intervention During Wait Times for Psychotherapy

Self-reported depression and anxiety symptom severity will be measured using the Patient Health Questionnaire Anxiety-Depression Scale (PHQ-ADS; Kroenke et al., 2016; 2019). The PHQ-ADS combines the Patient Health Questionnaire 9-item depression scale (PHQ-9) and 7-item Generalized Anxiety Disorder scale (GAD-7). Scores range from 0 to 48, with higher scores indicating greater symptom severity. The primary endpoint is at 2 weeks. Assessments will also be conducted at baseline, 5 weeks, 9 weeks, and 24 weeks.

Self-reported depression and anxiety symptom severity will be measured using the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS; Kroenke et al., 2016; 2019). Scores range from 0 to 48, with higher scores indicating greater symptom severity. Assessments are conducted at baseline, 2 weeks, 5 weeks, 9 weeks, and 24 weeks.

Self-reported depression and anxiety symptom severity will be measured using the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS; Kroenke et al., 2016; 2019). Scores range from 0 to 48, with higher scores indicating greater symptom severity. Assessments are conducted at baseline, 2 weeks, 5 weeks, 9 weeks, and 24 weeks.

Depressive symptoms assessed with the Patient Health Questionnaire-9 (PHQ-9) scale that is a part of the PHQ-ADS (Kroenke et al., 2016). The PHQ-9 measures the severity of depressive symptoms and has demonstrated high validity and reliability. Scores range from 0 (no depressive symptoms) to 27 (severe depressive symptoms).

Anxiety symptoms assessed with the Generalized Anxiety Disorder-7 scale (GAD-7) that is a part of the PHQ-ADS (Kroenke et al., 2016). The GAD-7 measures the severity of generalized anxiety symptoms and has demonstrated strong validity and reliability. Scores range from 0 (no general anxiety symptoms) to 21 (severe general anxiety symptoms)

Quality of life assessed with the European Quality of Life-5 Dimensions-5 Level (EQ-5D-5L; Herdman et al., 2001). This measure includes five dimensions-Mobility, Self-care, Usual activities, Pain/discomfort, and Anxiety/depression-each rated on a 5-point scale from 1 (no problems) to 5 (extreme problems).

Satisfaction assessed with the Client Satisfaction Questionnaire-8 (CSQ-8; Attkisson & Zwick, 1982), adapted for internet interventions. The CSQ-8 consists of 8 items rated on a 4-point Likert scale, with higher scores indicating greater satisfaction. The German version has demonstrated high reliability and validity (Kriz et al., 2008).

Negative treatment effects of UKADO assessed with the Negative Effects Questionnaire (NEQ; Rozental et al., 2019). This 20-item measure evaluates adverse effects during psychological treatments, including symptoms, therapy quality, dependency, stigma, and hopelessness.

Resource activation and problem mastery assessed with selected items from the Bern Post Session Report 2000, Patient and Therapist Versions (Flückiger et al., 2010), adapted for the digital intervention.

Therapeutic alliance measured with the Working Alliance Inventory for Guided Internet Interventions (WAI-I; Gomez Penedo et al., 2020), adapted to assess alliance with the study team. The 12 items assess agreement on therapeutic tasks, agreement on therapeutic goals, and emotional bond, rated on a 5-point Likert scale. Scores can range from 12 to 60, a higher score means a higher working alliance.

Treatment expectations assessed with the Treatment Expectancy Questionnaire (TEX-Q; Alberts et al., 2020; Shedden-Mora et al., 2023), covering six subscales: Treatment benefit, Positive impact, Adverse events, Negative impact, Process, and Behavioral control. Scores range from 0 to 10, with higher scores indicating greater expectations.

Qualitative interviews conducted with a subset of participants using a study-specific guide developed to explore participants' experiences with the intervention.

Impact of UBT on f2f therapy experience (assessed with study-specific questions)

Uptake of the UBT will be assessed at 2 weeks by reporting the number of patients who used the UBT (logged in).

Usage of (adherence to) the UBT will be assessed at 2 weeks with a composite adherence score based on pages visited, time spent, and user input.

Self-reported psychotherapy uptake will be assessed via online questionnaires by recording the number of patients opting out of face-to-face (f2f) therapy after UBT and the number of patients who started f2f psychotherapy at each timepoint.

Self-reported psychotherapy use will be assessed via online questionnaire to record the number of sessions attended at each timepoint.

The number and type of adverse events occurring during the study will be reported for the entire sample.