Randomized Controlled Trial of a Novel Mindfulness based on ‎Meta-Inner Humor for Co-occurrence of Anxiety, OCD, and Depressive Disorders

The primary hypotheses test whether MMIH reduces emotional distress (depression, anxiety, OCI-R) and increases life satisfaction. Secondary hypotheses focus on the effects of MMIH on reducing RNT, maladaptive meta-beliefs, psychological inflexibility, and enhancing mindfulness. The mechanism of change hypothesis examines whether changes in meta-beliefs predict improvements in symptoms and broader processes beyond mindfulness.

This study was a three-arm randomized controlled trial (RCT) following CONSORT 2010 and longitudinal ‎measurement at three time points: baseline, post-treatment, and 6-month follow-up ‎.‎

Participants were recruited from September 3 to May 17, 2025, using a multi-tiered referral and outreach strategy to enhance representativeness and reduce self-selection bias.

Eligibility criteria included: (a) meeting DSM-5 diagnostic criteria for at least one disorder in anxiety disorders, depressive disorders, and obsessive-compulsive and related disorders; (b) age 18 or older; and (c) provision of written informed consent. Exclusion criteria included: (a) current or past diagnosis of psychotic disorders, bipolar disorders, severe personality disorders, substance use disorders, or any debilitating medical condition (e.g., uncontrolled chronic illness); and (b) current suicidality.

MMIH is a 10-week manualized group therapy (90 minutes/week), delivered by ‎certified clinicians trained in the MMIH protocol.

Obsessive–Compulsive Inventory–Revised; Satisfaction with Life Scale; Meta-Inner Humor Scale; Mindful Attention Awareness Scale; Repetitive Thinking Questionnaire – 10 ' Acceptance and Action Questionnaire–II; Metacognitions Questionnaire–30; Self-Compassion Scale – Short Form; Patient Health Questionnaire – 9 item; State–Trait Anxiety Inventory

Participants will be stratified based on diagnosis severity (high/low) and gender, and will then be randomized using permuted block randomization (block size = 6). Randomization will be implemented through an independent and concealed sequence using the REDCap randomizer with a full audit trail. Group assignment will be double-blinded for both outcome assessors and participants. After confirming eligibility, participants will be randomly assigned to one of three study arms: Experimental group (MMIH intervention; n = 31), Placebo-control group (n = 31), and Waitlist control group (n = 31). An independent researcher, not involved in participant recruitment or intervention, will generate the randomization sequence and will oversee allocation concealment using Sequentially Numbered, Opaque, Sealed Envelopes (SNOSE). Researchers responsible for outcome assessment and statistical analysis will remain blinded to group assignments.

While participants will be blinded to intervention type, outcome assessors will remain blind to group allocation. Therapists and facilitators will be instructed to avoid disclosing any information related to group identity. Participants will be informed that they may receive one of three structured interventions as part of a mental health trial.

Information on the main outcome of the research will be shared.

Access begins 6 months after results are published.

Data and other scientific documentation can be made available to any person who requests it.

There are no specific restrictions.

To access the data, you can send a message to Dr. Mehdi Akbari's email address: Akbari.psy@gmail.com or m.akbari@khu.ac.ir

One month after the requester sends a message to one of the two emails mentioned in the previous section, individuals can receive the requested information.