Clinical and Biological Correlates of Obsessive-Compulsive Disorder and Online Mindfulness-Based Cognitive Therapy

Obsessive-Compulsive Disorder (OCD) is a common and potentially disabling psychiatric condition, characterized by intrusive and distressing thoughts (obsessions) and repetitive behaviors or mental acts (compulsions). Cognitive behavioral therapy, particularly exposure and response prevention, is considered a first-line treatment for OCD. However, a proportion of patients continue to experience clinically significant symptoms after treatment, highlighting the need for complementary therapeutic approaches.

Mindfulness-based interventions may help patients develop a less reactive and more accepting relationship with intrusive thoughts, emotions, and bodily sensations, potentially reducing the use of maladaptive strategies such as suppression, neutralization, and compulsions. Preliminary evidence suggests that mindfulness-based approaches may reduce OCD symptoms and may improve the acceptability of exposure-based treatment. However, evidence regarding synchronous, therapist-led online group interventions specifically adapted for OCD remains limited.

This study aims to evaluate the feasibility and acceptability of a specialized Mindfulness-Based Cognitive Therapy (MBCT) program for OCD, delivered online through synchronous videoconferencing. The manualized intervention (Didonna, 2022) integrates mindfulness practices with cognitive behavioral therapy, exposure and response prevention, acceptance, decentering, and self-compassion techniques.

The primary objective is to assess the feasibility and acceptability of the synchronous online intervention. Exploratory objectives are to evaluate changes in OCD symptoms and other clinical variables and to investigate associations between clinical characteristics, treatment response, and selected biological markers.

At least 42 adults aged 18-45 years with a diagnosis of OCD will be recruited at two participating centers in Italy. Participants will attend 11 weekly online group sessions conducted by trained therapists. The intervention may be provided alongside ongoing stable pharmacological treatment and other standard clinical care.

Clinical assessments: patients will undergo diagnostic and clinical assessment using the Structured Clinical Interview for DSM-5 (SCID-5-CV), including the personality disorders section (SCID-PD), and a medical and clinical history.

Clinical assessments will be performed at baseline, immediately after treatment, and at 3-month follow-up. Clinician-administered assessment will include the Yale-Brown Obsessive Compulsive Scale-2nd version (Y-BOCS-II) to assess OCD symptom severity. Self-report measures will assess depressive and anxiety symptoms, mindfulness, interoceptive awareness, dysfunctional obsessive beliefs, self-compassion, mind wandering, and general psychopathology.

Treatment acceptability and feasibility will be assessed through recruitment and dropout rates, treatment adherence, attendance, completion rates of assessment questionnaires, reasons for treatment discontinuation, treatment satisfaction, and home mindfulness practice. Participants will complete an ad hoc treatment satisfaction questionnaire at the end of treatment. Home practice time will be monitored during treatment and follow-up, and practice quality will be assessed using the Practice-Quality-Mindfulness (PQ-M) at predefined time points.

Biological assessments: patients recruited at Center 1 will provide blood and saliva samples before and after the intervention. Blood will be collected for RNA, DNA, plasma, and serum analyses; while saliva samples will be collected during the day to measure cortisol levels.

Patients with OCD.

Inclusion criteria

• Diagnosis of obsessive-compulsive disorder (OCD) according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)
• Age between 18 and 45 years
• Stable pharmacological treatment for at least 3 months prior to the start of the experimental intervention
• No previous experience with mindfulness meditation, or previous mindfulness meditation experience with no practice during the 12 months prior to study enrollment
• Ability and willingness to provide written informed consent.

Exclusion criteria

• Diagnosis of schizophrenia spectrum or other psychotic disorders, including schizoaffective disorder
• Diagnosis of bipolar and related disorders
• Major depressive disorder in an acute phase
• Active substance use disorder or alcohol use disorder as the primary diagnosis
• Personality disorders of clinically significant severity
• Documented major neurocognitive disorder. Neurological conditions or medical conditions with a clinically significant impact on cognitive or mental functioning
• Previous mindfulness meditation practice within the 12 months prior to study enrollment
• Inability or unwillingness to provide informed consent

Healthy subjects.

Inclusion criteria

• Age between 18 and 45 years, with age matching within a maximum difference of ±3 years from the corresponding index patient. In all cases, control participants must be at least 18 years and no older than 48 years
• Voluntary participation in the study.
• Ability and willingness to provide written informed consent

Exclusion criteria

• Age younger than 18 years
• History of psychiatric disorders, as assessed using the Structured Clinical Interview for DSM-5 Disorders - Clinician Version (SCID-CV)
• Intellectual developmental disorder.
• Current substance use disorder or alcohol use disorder
• Neurological disorders, including Parkinson's disease, major neurocognitive disorders, neurodegenerative syndromes, ataxias, multiple sclerosis, cerebrovascular events (stroke or transient ischemic attack [TIA]), central nervous system neoplasms, epilepsy, history of seizures, or clinically significant tremor
• Systemic medical conditions (e.g., diabetes mellitus, atherosclerosis, chronic arterial hypertension, or malignancies) requiring pharmacological treatment
• Current or previous mindfulness meditation practice within the 12 months prior to study enrollment