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This is a randomized controlled trial examining the efficacy and neural mechanisms of a standardized Mindfulness Intervention for Emotional Distress (MIED) in adults with subclinical emotional distress. One hundred and sixty participants will be randomly assigned to either an 8-week MIED program or an 8-week Progressive Muscle Relaxation (PMR) active control. The primary aim is to evaluate whether MIED reduces anxiety symptoms and reshapes multilevel emotional processing as measured by multimodal EEG (resting-state FAA/theta, Fast Periodic Visual Stimulation, and event-related potentials). Assessments occur at baseline (T1), post-intervention (T2), and 1-month follow-up.
Background. Emotional distress is a subclinical mental health condition characterized by persistent anxiety, depression, stress, and emotion dysregulation. Mindfulness interventions have shown efficacy across transdiagnostic emotional disorders, yet their neurocognitive mechanisms remain incompletely understood.
Objective. This study aims to (1) verify the dynamic intervention effects of MIED on emotional distress; (2) reveal neuroplastic changes across multiple levels of emotional processing; (3) explore associations between neural changes and symptom improvement; and (4) examine whether strategy acquisition is linked to neural remodeling.
Design. This is a two-arm, parallel-group, randomized controlled trial with single (outcomes assessor) blinding. Participants (N = 160) aged 18-50 with elevated psychological distress (K10 > 21) will be randomized (1:1; block sizes 4 and 6) to:
Experimental arm: MIED - 8 weeks of weekly 2.5-hour group sessions plus daily 15-minute app-based home practice.
Active comparator arm: PMR - 8 weeks of structurally matched weekly 2.5-hour group sessions plus daily 15-minute audio home practice.
Assessments. Baseline (T1), post-intervention (T2, within 2 weeks after Week 8), and 1-month follow-up (online). During the intervention, brief online tracking (GAD-7, PHQ-9) occurs at Weeks 2, 4, and 6.
Neuroimaging. Multimodal EEG includes: (a) 5-minute resting-state EEG (FAA, theta power); (b) Fast Periodic Visual Stimulation (FPVS; 6 Hz base frequency, 1.2 Hz oddball for emotional faces) to index automatic emotional processing; (c) Task-based ERP ( LPP at 400-800 ms ) during emotional picture rating to index controlled emotional processing.
Primary Mechanistic Outcome. LPP early-window (400-800 ms) mean amplitude under negative stimulus conditions.
Statistical Analysis. Primary efficacy analyses will use linear mixed-effects models (LMM) under the intention-to-treat (ITT) principle. Missing data will be handled by restricted maximum likelihood (REML) assuming MAR, with multiple imputation as a sensitivity analysis. Hierarchical multiple comparison control: primary outcome (GAD-7) at α = 0.05 (two-sided); key secondary outcome (PHQ-9) reported with nominal and corrected p-values; remaining psychological and EEG measures corrected by Benjamini-Hochberg FDR.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| PMR (Progressive Muscle Relaxation) | Active Comparator | A structured 8-week Progressive Muscle Relaxation program matched to MIED in frequency, duration, and format: weekly 2.5-hour group sessions plus daily 15-minute audio home practice. Participants progress from tension-release of major muscle groups to full-body relaxation. |
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| MIED (Mindfulness Intervention for Emotional Distress) | Experimental | A standardized 8-week transdiagnostic mindfulness program: weekly 2.5-hour group sessions plus daily 15-minute app-based home practice (iMIED). Content includes mindful breathing, body scan, mindful walking, and loving-kindness meditation. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| MIED | Behavioral | A standardized 8-week transdiagnostic mindfulness intervention (MIED) based on the Unified Protocol and contemporary mindfulness theory. Participants attend weekly 2.5-hour group sessions and complete daily 15-minute home practice via a mobile app (iMIED). Core practices include mindful breathing, body scan, mindful walking, and loving-kindness meditation. The program emphasizes four key strategies: engagement with life, distress tolerance, cognitive flexibility, and emotion-driven behavioral regulation. All sessions follow a structured manual to ensure fidelity. |
| Measure | Description | Time Frame |
|---|---|---|
| Generalized Anxiety Disorder-7（GAD-7） | The GAD-7 is a 7-item self-report measure of anxiety symptom severity over the past 2 weeks. Total scores range from 0 to 21. The primary analysis examines the Group × Time interaction using linear mixed-effects models across all six assessment points (Weeks 0, 2, 4, 6, 8, and 12). | Baseline (T1, Week 0), Week 2, Week 4, Week 6, post-intervention (T2, Week 8), and 1-month follow-up (Week 12) |
| Measure | Description | Time Frame |
|---|---|---|
| Patient Health Questionnaire（PHQ-9） | The Patient Health Questionnaire-9 (PHQ-9) is a 9-item self-report measure assessing the severity of depressive symptoms over the past two weeks. Total scores range from 0 to 27, with higher scores indicating more severe depressive symptoms (worse outcome). | Baseline (T1, Week 0), Week 2, Week 4, Week 6, post-intervention (T2, Week 8), and 1-month follow-up (Week 12) |
| Measure | Description | Time Frame |
|---|---|---|
| Meditation-Related Adverse Events Scale (MRAES-MBP) | The MRAES-MBP is a self-report measure assessing meditation-related adverse events experienced during participation in mindfulness-based programs, including their occurrence and severity. | Week 2, Week 4, Week 6, and Week 8 |
| Simplified adverse events questionnaire |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Qinsi Zheng | Contact | +86 13457651658 | qszheng25@stu.pku.edu.cn | |
| Xinghua Liu | Contact | +86 13371669818 | xinghua_liu@pku.edu.cn |
| Name | Affiliation | Role |
|---|---|---|
| Xinghua Liu, Dr. | School of Psychological and Congnitive Science,Peiking University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Peking University, School of Psychological and Cognitive Sciences | Recruiting | Beijing | Beijing Municipality | China |
Individual participant data (IPD) will not be made publicly available because the study involves sensitive mental health data and participant privacy must be protected. Requests for additional information regarding the study may be directed to the corresponding author.
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| ID | Term |
|---|---|
| D001008 | Anxiety Disorders |
| D003863 | Depression |
| ID | Term |
|---|---|
| D001523 | Mental Disorders |
| D001526 | Behavioral Symptoms |
| D001519 | Behavior |
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Due to the nature of the behavioral interventions, participants and interventionists cannot be blinded. However, outcome assessors conducting EEG and questionnaire evaluations at T1 and T2 will be blinded to group assignment. Data analysts will work with de-identified datasets using anonymous group codes until primary analyses are locked. If an unblinding event occurs, it will be documented and reported.
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| PMR | Behavioral | A structured 8-week Progressive Muscle Relaxation program matched to MIED in frequency, duration, and format. Participants attend weekly 2.5-hour group sessions and complete daily 15-minute audio-guided home practice. The program progresses from systematic tension-release of major muscle groups to full-body relaxation, controlling for non-specific therapeutic factors (group support, time, expectancy). All sessions are manualized to ensure consistent delivery. |
|
| Five Facet Mindfulness Questionnaire-20 (FFMQ-20) | The Five Facet Mindfulness Questionnaire-20 (FFMQ-20) is a 20-item self-report measure assessing trait mindfulness across five facets. Total scores range from 20 to 100, with higher scores indicating greater mindfulness (better outcome). | Baseline (T1，week 0) and post-intervention (T2, Week 8) |
| Distress Tolerance Scale (DTS) | The Distress Tolerance Scale (DTS) is a 15-item self-report measure assessing an individual's perceived ability to tolerate and manage emotional distress. Total scores range from 15 to 75, with higher scores indicating greater distress tolerance (better outcome). | Baseline (T1，week 0) and post-intervention (T2，week 8) |
| Cognitive Flexibility Inventory (CFI) | The Cognitive Flexibility Inventory (CFI) is a 20-item self-report measure assessing cognitive flexibility. Total scores range from 20 to 140, with higher scores indicating greater cognitive flexibility (better outcome). | Baseline (T1，week0) and post-intervention (T2，week8) |
| Excessive Emotional Behavior Scale (EEBS) | EEBS is a self-report measure assessing the tendency to engage in excessive emotional behaviors in response to emotional distress. Higher scores indicate greater levels of excessive emotional behavior. | Baseline (T1，week 0) and post-intervention (T2，week8) |
| Engagement with Life Scale (ELS) | ELS is a self-report measure assessing the extent to which individuals engage in meaningful and valued life activities despite experiencing emotional distress. Higher scores indicate greater engagement with life. | Baseline (T1，week0) and post-intervention (T2，week8) |
| Chinese Perceived Stress Scale (CPSS) | The Chinese Perceived Stress Scale-14 (CPSS-14) is a 14-item self-report measure assessing perceived stress during the past month. Total scores range from 0 to 56, with higher scores indicating greater perceived stress (worse outcome). | baseline（T1，week 0），post-intervention（T2，week8） |
| Late Positive Potential (LPP) early window (400-800 ms) | Late Positive Potential (LPP; 400-800 ms mean amplitude) is an ERP component reflecting sustained controlled processing of emotional stimuli. Mean LPP amplitude within the 400-800 ms time window will be quantified at CPz, Cz, P3, Pz, and P4 during a 20-minute emotional picture rating task. Based on the best available evidence and theoretical rationale from previous mindfulness and emotion regulation studies, LPP was selected as a candidate mechanistic outcome. | Baseline (T1，week 0) and post-intervention (T2，week 8) |
| Frontal Alpha Asymmetry (FAA) | Frontal Alpha Asymmetry (FAA; 8-13 Hz log-transformed alpha power difference) is a resting-state EEG measure reflecting hemispheric asymmetry in frontal cortical activity and has been associated with affective processing, emotion regulation, and approach-withdrawal motivational tendencies. FAA will be calculated as the log-transformed alpha power difference between homologous frontal electrode pairs (e.g., ln[F4] - ln[F3]) during a 5-minute resting-state EEG recording. Based on the best available evidence and theoretical rationale from previous mindfulness and emotion regulation studies, FAA was selected as a candidate mechanistic outcome. | Baseline (T1，week 0) and post-intervention (T2，week 8) |
| Frontal theta power | Frontal theta power (4-8 Hz) is a resting-state EEG measure associated with cognitive control, attentional regulation, and emotion regulation. Absolute or relative theta power within the 4-8 Hz frequency band will be quantified from frontal electrodes (e.g., Fz, F3, and F4) during a 5-minute resting-state EEG recording. Based on the best available evidence and theoretical rationale from previous mindfulness and cognitive control studies, frontal theta power was selected as a candidate mechanistic outcome. | Baseline (T1，week 0) and post-intervention (T2，week 8) |
| Fast Periodic Visual Stimulation Signal-to-Noise Ratio (FPVS-SNR) | Fast Periodic Visual Stimulation Signal-to-Noise Ratio (FPVS-SNR) is an EEG-derived measure quantifying neural responses to periodically presented emotional visual stimuli. Change in FPVS-SNR from baseline to post-intervention will be assessed during the emotional fast periodic visual stimulation task.Based on the best available evidence and theoretical rationale, FPVS-SNR was selected as a candidate mechanistic outcome to assess changes in visual emotional processing following the intervention. | Baseline (T1，week 0) and post-intervention (T2，week 8) |
| Kessler Psychological Distress Scale (K10) | The Kessler Psychological Distress Scale (K10) is a 10-item self-report measure assessing non-specific psychological distress during the past four weeks. Total scores range from 10 to 50, with higher scores indicating greater psychological distress (worse outcome). | Baseline (T1，week 0) and post-intervention (T2, Week 8)] |
A simplified safety monitoring questionnaire administered biweekly to the PMR group to assess somatic discomfort and emotional reactions related to muscle relaxation practice. |
| Week 2, Week 4, Week 6, and Week 8 |
| Credibility/Expectancy Questionnaire (CEQ) score | A 6-item measure of intervention credibility and improvement expectancy, administered to assess and control for non-specific expectancy effects as a covariate in primary efficacy analyses. | Baseline (T1) and after the first group session (Week 1) |