App-Based Self-Management for Somatic Symptom Disorder and MUS: A Pilot Study

NCT07296406 | Enrolling By Invitation

• 1 other identifier: 3-2024-0119
• Study Type: interventional
• Target: 110
• Locations: 1 country
• Sites: 1

Brief Summary

Objectives The primary objective of this study is to evaluate the effectiveness of an eight-week self-management mobile application for adults experiencing somatic symptom disorder (SSD) or medically unexplained symptoms (MUS). Improvement will be assessed using the PHQ-15. The secondary objective is to examine changes in clinical symptoms and physiological indicators following app use, as well as to assess the acceptability and usability of the intervention. Scientific Rationale Somatic symptoms without clear medical explanation account for 15-30% of primary care visits (Peveler et al., 1997; Fink et al., 1999; Ko et al., 2011). Diagnostic terminology has evolved from somatoform disorders in DSM-IV and MUS to SSD in DSM-5, which emphasizes distressing symptoms accompanied by maladaptive thoughts, emotions, or behaviors (Scott et al., 2022). SSD is frequently associated with alexithymia, emotional suppression, and difficulty regulating anger, consistent with theories of somatization as the bodily expression of unprocessed affect (Anuk \& Bahadir, 2017; Liu et al., 2011). These difficulties contribute to interpersonal impairment and excessive health care use, often resulting in frustration for clinicians (Orzechowska et al., 2020). Psychological treatments, including CBT, MBSR, MBCT, and ACT, have demonstrated efficacy in reducing symptom burden across conditions such as IBS, fibromyalgia, tinnitus, and chronic fatigue (Hauge et al., 2015; Kikuchi et al., 2020; Roland et al., 2015). These therapies share mechanisms such as enhancing mind-body awareness, reducing physiological hyperarousal, and promoting adaptive coping and acceptance (Aktas et al., 2019; Jing et al., 2019). However, barriers to dissemination remain, as patients with SSD often reject psychological explanations, engage in medical shopping, and maintain strong somatic attributions (Brown, 2007; Harris et al., 2009). Digital interventions offer a scalable solution by providing psychoeducation on mind-body connections, CBT- and mindfulness-based strategies, stress management tools, and behavioral monitoring in an accessible, daily-life format. Evidence suggests that internet- and app-based CBT programs can improve somatic distress and related outcomes, while also reducing treatment costs and improving adherence (Van et al., 2022). Physiological measures such as heart rate variability (HRV) provide an objective biomarker of stress regulation. Lower HRV reflects reduced resilience and greater emotional dysregulation, while higher HRV indicates excessive arousal or impaired recovery. Despite theoretical links between autonomic regulation and somatization, few studies have examined HRV responses in SSD populations alongside psychological interventions. This study addresses that gap. Study Design A randomized controlled trial will recruit 110 adults aged ≥19 years who report significant somatic distress. After screening and informed consent, participants will be randomly assigned (1:1) to intervention (n=55) or control (n=55) using an R-generated allocation table managed independently of investigators. Baseline assessments include standardized questionnaires and HRV measurement. The intervention group will use the mobile application for eight weeks, while the control group will continue treatment as usual. After eight weeks, both groups will complete follow-up questionnaires and HRV measurement. Subsequently, the intervention group will discontinue app use, and the control group will be offered app access. An additional follow-up survey will be conducted online for both groups at 16 weeks. Expected Impact This study will provide empirical evidence on the efficacy, usability, and acceptability of a digital intervention for SSD and MUS. By integrating self-management strategies with physiological monitoring, it aims to advance scalable, evidence-based approaches for a population that has historically been difficult to treat within traditional medical models.

Conditions

Somatic Symptom Disorder

Outcome Measures

Primary Outcomes (1)

• Somatic Symptom Severity (Patient Health Questionnaire-15; PHQ-15)

  The primary outcome is the change in somatic symptom severity measured by the Patient Health Questionnaire-15 (PHQ-15). The PHQ-15 is a 15-item self-report scale developed to assess the severity of somatic symptoms in primary care (Kroenke et al., 1998) and validated in psychiatric outpatient populations (Han et al., 2009). Scores range from 0 to 30, with higher scores indicating greater somatic symptom burden.

  Baseline, 8 weeks after intervention start (V2), 16 weeks after intervention start (V3)

Secondary Outcomes (13)

• Somatic Symptom Disorder B-Criteria Scale (SSD-12)

  Baseline, 8 weeks after intervention start, and 16 weeks after intervention start

• Patient Health Questionnaire-9 (PHQ-9)

  Baseline, 8 weeks after intervention start, and 16 weeks after intervention start

• Generalized Anxiety Disorder-7 (GAD-7)

  Baseline, 8 weeks after intervention start, and 16 weeks after intervention start

• Liebowitz Social Anxiety Scale, Self-Rated (LSAS-SR)

  Baseline, 8 weeks after intervention start, and 16 weeks after intervention start

• Korean Version of the Five Facet Mindfulness Questionnaire - Short Form (FFMQ-SF)

  Baseline, 8 weeks after intervention start, and 16 weeks after intervention start

Study Arms (2)

App Intervention Group

EXPERIMENTAL

Participants in this group will use the mobile self-management application for somatic symptom disorder and medically unexplained symptoms for 8 weeks, in addition to receiving their usual care.

Behavioral: Arm I (App Intervention); Behavioral: Arm II (Waitlist Control)

Waitlist Control Group

NO INTERVENTION

Participants in this group will continue treatment as usual for 8 weeks without access to the mobile application. After the primary 8-week period, they will be offered access to the application.

Interventions

Arm I (App Intervention) BEHAVIORAL

Participants assigned to the intervention group will use a mobile self-management application designed for individuals with somatic symptom disorder and medically unexplained symptoms. The app delivers psychoeducation, CBT- and mindfulness-based therapeutic content, stress management tools, and behavioral monitoring over a 8-week period, in addition to participants' usual care.

App Intervention Group

Arm II (Waitlist Control) BEHAVIORAL

Participants in the control group will continue treatment as usual for 8 weeks without access to the mobile application. After completion of the 8-week primary endpoint, they will be offered access to the mobile application.

App Intervention Group

Eligibility Criteria

• Age: 19 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 19 years or older
• PHQ-15 score of 4 or higher
• Presence of medically unexplained physical symptoms (MUS)
• No significant impairment in reading or writing ability
• Familiarity with smartphone and internet use

You may not qualify if:

• Current diagnosis of substance use disorder (alcohol or drugs)
• Current diagnosis of schizophrenia or bipolar disorder, or presence of psychiatric symptoms deemed by the clinician to interfere with participation
• Currently receiving psychotherapy specifically for somatic symptoms
• Diagnosis of developmental disorders such as autism or intellectual disability, or evidence of significant cognitive impairment
• Any other medical condition deemed by the clinician to make participation inappropriate
• Inability to continue participation due to smartphone malfunction or lack of sufficient smartphone skills

Sponsors & Collaborators

• Gangnam Severance Hospital: lead

Study Sites (1)

Gangnam Severance Hospital

Seoul, 06273, South Korea

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Masking Details: Open-label trial; no masking of participants, care providers, investigators, or outcome assessors.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Clinical Associate Professor

Model Details: Randomized, open-label, parallel assignment trial with two arms (intervention vs. waitlist). Participants in the intervention group will use the mobile application for 8 weeks (V1-V2) followed by a 8-week follow-up period without app use (V2-V3). Participants in the waitlist control group will receive usual care for the first 8 weeks (V1-V2), and then begin using the mobile application for 8 weeks (V2-V3).

Study Record Dates

• First Submitted: September 9, 2025
• First Posted: December 22, 2025
• Study Start: May 24, 2024
• Primary Completion: March 30, 2026
• Study Completion (Estimated): May 23, 2026
• Last Updated: December 22, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

KR (1)