Bergen Four-Day Treatment (B4DT) for Obsessive-Compulsive Disorder

Changes in OCD symptoms will be assessed using the Yale-Brown Obsessive-Compulsive Scale, Self-Report (Y-BOCS-SR), a ten-item self-report measure with each item rated from 0 to 4. Total scores range from 0 to 40, with higher scores indicating more severe symptoms.

In addition to the Y-BOCS, changes in OCD symptoms will be assessed using the Obsessive-Compulsive Inventory - Revised (OCI-R), which consists of 18 items, each rated from 0 to 4, with total scores ranging from 0 to 72 points. Higher scores indicate more severe symptoms.

Patients will be asked about their satisfaction with the treatment using the Client Satisfaction Questionnaire (CSQ-8). The CSQ-8 consists of eight items, each rated on a scale from 1 to 4, with total scores ranging from 8 to 32. Higher scores indicate greater satisfaction with the treatment.

Patients' treatment expectations will be assessed using the Credibility and Expectancy Questionnaire (CEQ). The CEQ includes six items: four rated from 1 to 9 and two from 0% to 100%, with higher scores indicating greater expectations and confidence in the treatment.

The acceptability, appropriateness, and feasibility of the treatment will be assessed among healthcare professionals using a combination of three subscales: the Acceptability of Intervention Measure (AIM), Intervention Appropriateness Measure (IAM), and Feasibility of Intervention Measure (FIM). The AIM, IAM, and FIM each consist of four items rated on a five-point scale. Accordingly, the total score for each scale ranges from 4 to 20 points. The total 12-item score ranges from 12 to 60, with higher scores indicating greater overall treatment acceptability.

Secondarily, the aim is to investigate whether there are changes in patients' depressive symptoms during the treatment. Depressive symptoms will be assessed using the Patient Health Questionnaire (PHQ-9), which consists of nine items, each rated from 0 to 3, with total scores ranging from 0 to 27. Higher scores indicate more severe depressive symptoms.

In addition to depressive symptoms, the aim is to examine whether there are changes in patients' anxiety symptoms during the treatment. Anxiety symptoms will be assessed using the Generalized Anxiety Disorder Scale (GAD-7), which consists of seven items scored from 0 to 3, with total scores ranging from 0 to 21. Higher scores indicate more severe anxiety symptoms.

Work and social functioning will be assessed using the Work and Social Adjustment Scale (WSAS), a five-item measure rated on a Likert scale from 0 ("Not at all") to 8 ("Very much"). Total scores range from 0 to 40, with higher scores indicating greater impairment in work and social functioning.

General wellbeing will be assessed using the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS), which consists of 14 items rated on a five-point Likert scale from 1 "Never" to 5 "All the time," yielding total scores from 14 to 70. Higher scores indicate higher perceived wellbeing.

Quality of life will be assessed using the EuroQol 5-Dimension Questionnaire (EQ-5D), which consists of five items scored from 1 to 5, with total scores ranging from 5 to 25. Higher scores indicate lower perceived well-being. In addition, the EQ-5D includes a one-item scale for self-assessed well-being ranging from 0 to 100%. Higher percentages indicate higher perceived well-being.