Psychological Treatment for Persistent Fatigue

Treatment adherence will be assessed by evaluating how many sessions (face-to-face and video-based) the patient received, how many modules of the internet-delivered material the patient accessed, and the amount of time the patient spent in the online treatment platform (data extracted from the platform).

Further, number of drop-outs (i.e., patients who discontinued treatment before treatment completion) will be analyzed

Assessed using the Credibility/Expectancy Questionnaire (C-Scale). The C-Scale is a 5-item measure, scale range is 0 to 50 points with higher scores indicating higher treatment credibility.

Client Satisfaction Questionnaire (CSQ-8). Total scores range from 8 to 32, with higher scores indicating greater treatment satisfaction.

Assessed using the Working Alliance Questionnaire (WAI - short version). Scale range is from 6 to 42 with higher scores indicating a better percieved working alliance.

The Negative Effects of Treatment Questionnaire (NEQ-20). The self-report measure consists of three parts. First, respondents endorse specific items in case they have occurred or not during treatment, yes/no (dummy coded as a variable: 1/0). Second, the respondents rate how negatively the negative effect was on four-point Likert-scale, ranging from "Not at all" to "Extremely", 0-4 ("0" being minimum and "4" being maximum). Third, the respondents attribute the negative effect to "The treatment I received" (1) or "Other circumstances" (0) (dummy coded as a variable: 1/0).

Post-treatment, patients will be asked open-ended questions regarding their perception of the different components of the treatment, how much time they spent working with the treatment, and their thoughts about the usability of the digital platform.

The recruitment procedure will be evaluated by accessing data from ALMA (a fully automated clinical desicion-support in the medical journal). ALMA aggregates anonymous data regarding number of times the algorithm has been activated and the number of times it has resulted in a referral to the study platform where screening for study inclusion is completed. Of those who complete screening, we will assess the proportion of patients who are included or excluded in the study.

Data-collection procedures will be assessed by evaluating data-attrition at the various measurement points.

Fatigue severity (self-rated) using the Checklist Individual Strenghts- Fatigue severity subscale. The domain Fatigue severity contains 8 items scored on a 7-point Likert scale (range 8-56; higher scores=more severe fatigue). A score above 35 points on the CIS-F indicates severe fatigue.

Subscale in the Checklist Individual Strengths Questionnaire (CIS), 5 items. Scale range: 5 to 35 with higher scores representing more problems concentrating.

Subscale in the Checklist Individual Strengths Questionnaire (CIS), 3 items. Scale range: 3 to 21 with higher scores representing less physical activity.

Subscale in the Checklist Individual Strengths Questionnaire (CIS), 4 items. Scale range: 4 to 28 with higher scores representing less motivation.

Patient Health Questionnaire-9 (PHQ-9). Scale range is from 0 to 27, higher scores representing more depressive symptoms Note: the suicide-item will be administered every three weeks during the treatment phase.

Physical Health Questionnaire-15 (PHQ-15). Scale range is from 0 to 30, higher scores representing more somatic symptoms

The General Anxiety Questionnaire (GAD-7). Scale range is from 0 to 21, higher scores representing more anxiety.

The Insomnia Severity Inventory (ISI) 7 items. Scale range is from 0 to 28, higher scores representing higher insomnia severity.

NOTE: an additional item will be added to assess hypersomnia.

The Perceived Stress Scale (PSS-10). Scale range is from 0 to 40, higher scores representing a higher level of perceived stress.

The Shirom-Melamed Burnout Questionnaire (SMBQ-18). Scale range is from 0 to 6, higher scores representing a higher level of burnout.

The Self-rated health questionnaire (SRH-5). A single item with 5 response-categories, 0 (very bad health); 4 (very good health)

Cognitive and Behavioral Responses to Symptoms Questionnaire (CBRQ), 18-items. The scale assesses six domains: Fear avoidance (3 items, scale range 0-12); Damage beliefs (3 items, scale range 0-12); Embarrassment avoidance (3 items, scale range 0-12); Symptom focusing (3 items, scale range 0-12); All-or-nothing behaviour (3 items, scale range 0-12); Resting behaviour (3 items, scale range 0-12).

The General self-efficacy scale (GSE), 10 items. Scale range is from 10 to 40, higher scores representing a higher level of self-efficacy.

World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0), 12 items. Scoring from 0 (maximum functional disability) to 100 (no functional disability)

the Work and Social Adjustment Scale (WSAS), 5 items. Scale range 0 to 40 with higher scores representing better work and social adjustment.

Treatment fidelity will be assessed by audio recording all synchronous treatment sessions, of which a random selection will be assessed for fidelity using checklists that correspond to the central treatment components in each phase of the treatment.

When all treatments have been completed in the study, semi-structured interviews will be conducted with up to 10 included patients and up to three therapists. These will tap deeper, qualitative information about perceptions of working with the treatment and the data-collection procedures. All interviews will be audio recorded and transcribed for thematic content analysis.

a survey based on the "Triple P Systems Implementation Outcomes: Acceptability, Appropriateness, and Feasibility of intervention measure" will be disseminated to healthcare staff at participating primary health care clinics, to which they respond anonymously.