Clinical and Biological Correlates of Obsessive-Compulsive Disorder and Online Mindfulness-Based Cognitive Therapy (MIND-DOC)

Participants will receive a manualized Mindfulness-Based Cognitive Therapy (MBCT) program for obsessive-compulsive disorder (OCD), integrating cognitive-behavioral therapy, exposure techniques, mindfulness, decentering, acceptance, and self-compassion practices.

The intervention is a manualized Mindfulness-Based Cognitive Therapy (MBCT) program for OCD that integrates cognitive-behavioral therapy, exposure techniques, mindfulness, decentering, acceptance, and self-compassion practices (Didonna, 2022). The program aims to improve participants' ability to relate to internal experiences and reduce reactive patterns such as rituals and compulsions. Groups of 8-10 patients will receive the intervention online via synchronous videoconference. The program consists of 11 weekly sessions, including a 1.5-hour session involving family members and/or partners and a 6-hour intensive practice day.

The Y-BOCS-II is a clinician-administered semi-structured interview used to assess the presence and severity of obsessive-compulsive disorder (OCD) symptoms. The scale consists of 10 severity items, each rated from 0 (no symptoms) to 5 (extreme symptoms). The total score ranges from 0 to 50, where higher scores indicate greater symptom severity. A decrease in the score reflects clinical improvement.

Recruitment rate will be calculated as the percentage of eligible participants who enroll in the study among all participants assessed for eligibility.

Treatment dropout rate will be calculated as the percentage of participants who discontinue treatment before completing the intervention.End of Treatment (Week 11).

Treatment attendance rate will be calculated as the percentage of scheduled treatment sessions attended by each participant.

Assessment questionnaire completion rate will be calculated as the percentage of scheduled assessment questionnaires completed by participants.

Participant satisfaction will be assessed using a study-specific 19-item questionnaire developed for this trial. Each item is rated on a 5-point Likert scale (1 = not at all; 5 = very much), yielding a total score ranging from 19 to 95. Higher total scores indicate a more favorable evaluation of the treatment program, including its perceived usefulness and acceptability, group experience, facilitators, and online treatment modality.

Home mindfulness practice time will be assessed as the total amount of time spent practicing mindfulness at home during the treatment and follow-up periods.

The quality of home mindfulness practice will be assessed using the Practice-Quality-Mindfulness (PQ-M) scale at predefined assessment time points. The PQ-M consists of six items rated on a visual analog percentage scale ranging from 0% to 100%. The total score is calculated as the mean of the six items, with higher scores indicating better quality of home mindfulness practice.

The Beck Depression Inventory-II (BDI-II) is a self-report questionnaire designed to assess the severity of depressive symptoms. Each item is rated on a 4-point scale ranging from 0 to 3, reflecting increasing severity of the symptom.

The Beck Anxiety Inventory (BAI) is a 21-item self-report questionnaire designed to measure the severity of anxiety symptoms over the past week. Each item is rated on a 4-point scale ranging from 0 (not at all) to 3 (severely). The total score ranges from 0 to 63, with higher scores indicating greater anxiety severity.

The Five Facet Mindfulness Questionnaire-Short Form (FFMQ-SF) is a 24-item self-report instrument used to assess five facets of mindfulness: Observing, Describing, Acting with Awareness, Non-judging of Inner Experience, and Non-reactivity to Inner Experience. Each item is scored on a 5-point Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true). The total score is calculated by summing all items and ranges from 24 to 120, with higher scores indicating higher levels of mindfulness.

The Multidimensional Assessment of Interoceptive Awareness (MAIA-2) is a self-report questionnaire designed to evaluate multiple dimensions of individuals' awareness and perception of internal bodily sensations. The questionnaire assesses different aspects of interoceptive awareness, including noticing bodily sensations, emotional awareness, attention regulation, and the ability to respond to bodily sensations in an adaptive manner. Higher scores indicate greater adaptive interoceptive awareness.

The Obsessional Beliefs Questionnaire-20 (OBQ-20) is a 20-item self-report instrument designed to assess dysfunctional cognitive beliefs and attitudes critical to the development and maintenance of OCD. The scale evaluates four main domains: 1) Responsibility, 2) Threat Estimation, 3) Perfectionism, and 4) Importance/Control of Thoughts. Each item is rated on a 7-point Likert scale ranging from 1 (disagree very much) to 7 (agree very much). The total score is obtained by summing all 20 items and ranges from 20 to 140, with higher scores indicating a greater presence or severity of dysfunctional obsessional beliefs.

The Self-Compassion Scale-Short Form (SCS-SF) is a 12-item self-report questionnaire designed to assess an individual's level of self-compassion. Each item is rated on a 5-point Likert scale ranging from 1 (almost never) to 5 (almost always). Higher scores indicate a greater level of self-compassion.

The Mind-Wandering Questionnaire (MWQ) is a 5-item self-report instrument designed to measure trait levels of task-unrelated thought (mind-wandering). Each item is rated on a 6-point Likert scale ranging from 1 (almost never) to 6 (almost always). Higher total scores indicate a greater propensity or frequency of mind-wandering.

The Global Severity Index (GSI) is the primary summary score of the Symptom Checklist-90-Revised (SCL-90-R), a 90-item self-report questionnaire designed to evaluate a broad range of psychological symptoms and psychopathology. Each of the 90 items is rated on a 5-point Likert scale ranging from 0 (not at all) to 4 (extremely). The GSI raw score ranges from 0 to 4, with higher scores indicating a greater overall level of psychological distress and symptom severity.