Exposure-Based Treatment for Undifferentiated Somatic Symptom Disorder (SOMEX0)

Single-Arm Feasibility Study of Exposure-Based Treatment for Undifferentiated Somatic Symptom Disorder

This study investigates the feasibility of a general exposure-based treatment protocol that is intended to work for a large variety of patient groups with a clinically significant preoccupation with physical symptoms. This is a prospective single-group study based at Karolinska Institutet, Stockholm, Sweden, where 40 adults with DSM-5 somatic symptom disorder are enrolled in 8 weeks of therapist-guided exposure-based treatment via the Internet. Exposure is based on general principles but tailored to suit the needs of each patient. Outcomes include patient-reported credibility and expectancy, adherence to the treatment protocol, client satisfaction, and negative events. Within-group effects will also be quantified and discussed in relation to the existing literature.

Study Overview

• Status: Completed
• Conditions: Somatic Symptom Disorder
• Intervention / Treatment: Behavioral: Exposure

Detailed Description

Background:

A substantial portion of patients in routine care suffer from a recurrent preoccupation with physical symptoms, which often leads to substantial suffering and impairment. Exposure-based treatment - where the patient systematically seeks out that which gives rise to unwanted sensations, cognitions, or behavior - has been found to lead to beneficial effects in several types of symptom preoccupation. Yet, this form of treatment is rarely offered in routine care. This may be partially because existing treatment protocols have been developed for specific symptom clusters (e.g., functional somatic syndromes such as irritable bowel syndrome and fibromyalgia) or specific unwanted responses to symptoms (e.g., the fear of having a severe illness), and that many clinics do not have the resources to offer all these specialized protocols in parallel. An alternative approach could be to base exposure treatment on a more general protocol that may be tailored to suit a larger variety of patient groups who suffer from a recurrent preoccupation with physical symptoms. However, it is yet unclear if the use of such a general treatment protocol for symptom preoccupation would be feasible, for example in terms of patient-reported credibility, adherence, identification with the rationale, and general client satisfaction.

Aim:

To investigate the feasibility of delivering exposure-based treatment using a general protocol for clinically significant symptom preoccupation, without selecting patients based on any specific symptom cluster (such as a functional somatic syndrome) or specific unwanted response to physical symptoms (such as a frequent fear of illness).

Design:

This is a prospective single-group feasibility study based at Karolinska Institutet, Stockholm, Sweden, where 40 adults with somatic symptom disorder according to the Diagnostic and statistical manual of mental disorders 5 (DSM-5) are enrolled in 8 weeks of therapist-guided exposure-based treatment that is delivered via the Internet. Various aspects of feasibility are assessed; most notably: patient-reported credibility and expectancy, adherence to the treatment protocol, client satisfaction, and negative events. Within-group effects are also quantified.

• Study Type: Interventional
• Enrollment (Actual): 33
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Stockholm, Sweden, 17165
    • Karolinska Institutet

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• DSM-5 somatic symptom disorder
• Interest in 8-week intensive psychological treatment to reduce distress and the impact of physical symptoms
• At least 18 years old
• Living in Sweden
• Fluent in Swedish
• Complete pre-treatment assessment

Exclusion Criteria:

• Preoccupation with physical symptoms better explained by another psychiatric condition such as illness anxiety disorder, panic disorder, or obsessive-compulsive disorder
• Severe psychiatric condition, such as bipolar disorder, suicidal ideation, or psychosis
• Medical risks associated with participating in exposure-based treatment, or somatic condition - or treatment for somatic condition - that is an obstacle to participating in exposure-based treatment
• Non-stable continuous pharmacotherapy (dosage changed during the past 4 weeks) and the drug is likely to affect outcome measures (primarily: antidepressants, anticonvulsants, benzodiazepines, nonbenzodiazepines, opioids)
• Alcohol or substance use that is a clear obstacle to therapy
• Planned absence for more than 1 week of the treatment period

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Internet-delivered exposure-based treatment; Eight weeks of therapist-guided exposure-based treatment delivered via the Internet.	Behavioral: Exposure; Systematic confrontation with stimuli associated with symptom-related distress, to achieve therapeutic changes in cognitions or behavior

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility 1: Distribution of Physical Symptoms	According to the Patient Health Questionnaire-15 (PHQ-15, theoretical range: 0-30, higher score indicates more distressing physical symptoms)	Pre-treatment assessment (within 2 weeks before treatment)
Feasibility 2: Credibility/Expectancy Based on the Credibility/Expectancy Scale	Theoretical range: 0-50, higher score indicates higher credibility/expectancy	Week 3 of treatment
Feasibility 3: Adherence to the Protocol #1: Percentage Completed Modules in the Sample as a Whole	Preregistered target: at least 60% completed modules in the sample as a whole. In this study, all participants were enrolled in the same type of treatment and were thus offered to work with the same treatment modules. This outcome was the proportion of modules completed in total by all participants, out of the total modules available to all participants.	Adherence data collected over the entire course of the treatment, up to 8 weeks.
Feasibility 4: Patient-reported Adequacy of Rationale as Assessed Using a Questionnaire Developed Specifically for This Purpose (Theoretical Range: 0-10)	From 0 ("not at all relevant") to 10 ("extremely relevant"). Was originally intended to be administered at week 3, but was administered post-treatment due to an administrative error	Post-treatment assessment (immediately after treatment, completed within 45 days)
Feasibility 5: Adequacy of the Measurement Strategy	Preregistered target: less than 30% missing data at post-treatment, and at least 75% finding the measurement strategy acceptable (less than 7 on a scale from 0 ["Not at all stressful/bothering"] to 10 ["Extremely stressful/bothering"])	Post-treatment assessment (immediately after treatment, completed within 45 days)
Feasibility 6: Satisfaction With Treatment as Indicated by a Mean Client Satisfaction Questionnaire (CSQ-8) Score of at Least 22	Theoretical range: 8-32, higher score indicates higher satisfaction. This sum score is based on 8 items, each scored 1-4.	Post-treatment assessment (immediately after treatment, completed within 45 days)
Feasibility 7a: Adverse Events Measured Using Free-text Items #1: Total Number of Reported Events	The respondent was instructed to describe up to three adverse events.	Post-treatment assessment (immediately after treatment, completed within 45 days)
Feasibility 7b: Adverse Events Measured Using the 20-item Negative Effects Questionnaire (NEQ-20)	Theoretical range: 0-80, higher score indicates more severe adverse events	Post-treatment assessment (immediately after treatment, completed within 45 days)
Feasibility 3: Adherence to the Protocol #2: Percentage of Participants Completing at Least 2 Exposure Exercises	Preregistered target: at least 50% of participants completing at least 2 exposure exercises	Adherence data collected over the entire course of the treatment, up to 8 weeks.
Feasibility 7a: Adverse Events Measured Using Free-text Items #2: Number of Participants Who Reported at Least One Adverse Event	The respondent was instructed to describe up to three adverse events.	Post-treatment assessment (immediately after treatment, completed within 45 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Alcohol Use Disorders Identification Test (AUDIT)	Theoretical range: 0-40, higher score indicates more problematic alcohol use	Screening only
Drug Use Disorders Identification Test (DUDIT)	Theoretical range: 0-44, higher score indicates more problematic substance use	Screening only
Working Alliance Inventory (WAI)	Theoretical range: 6-42, higher score indicates better relationship with the therapist	Week 3 of treatment
Patient Health Questionnaire-15 (PHQ-15)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-30, higher score indicates more distressing physical symptoms	Screening, pre-treatment assessment (within 2 weeks before treatment), weekly during treatment, Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
Somatic Symptom Disorder-B Criteria Scale (SSD-12)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-48, higher score indicates higher degree of preoccupation with symptoms	Screening, pre-treatment assessment (within 2 weeks before treatment), weekly during treatment, Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
Symptom Preoccupation Scale (Preliminary Scale)	Under development, higher score indicates higher degree of preoccupation with symptoms. This is to be regarded as an item pool that will be further analyzed in 2024-2025, and in conjunction with data from other clinical trials. As of September 2023, it is therefore not yet possible to provide a theoretical range for this scale, and it is also not possible to provide outcomes.	Screening, pre-treatment assessment (within 2 weeks before treatment), weekly during treatment, Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
14-item Health Anxiety Inventory (HAI-14)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-42, higher score indicates more health anxiety	Screening, pre-treatment assessment (within 2 weeks before treatment), Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
Anxiety Sensitivity Index (ASI)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-64, higher score indicates more anxiety sensitivity	Screening, pre-treatment assessment (within 2 weeks before treatment), post-treatment assessment Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
GAD-7	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-21, higher score indicates more general anxiety	Pre-treatment assessment (within 2 weeks before treatment), post-treatment assessment Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment
Patient Health Questionnaire (PHQ-9)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-27, higher score indicates more symptoms of depression	Screening, pre-treatment assessment (within 2 weeks before treatment), weekly during treatments (suicidality), post-treatment assesment (immediately after treatment, completed within 45 days), 3 months after treatment
12-item WHO Disability Assessment Schedule 2.0 (WHODAS 2.0)	Change pre-post, as derived from linear mixed effects regression models fitted by maximum likelihood estimation using data from all 33 participants, and fitted on all 11 measurement points over the treatment phase (from pre-treatment to post-treatment). Theoretical range: 0-100, higher score indicates more disability	Screening, pre-treatment assessment (within 2 weeks before treatment), post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment

Collaborators and Investigators

• Sponsor: Karolinska Institutet
• Investigators: Principal Investigator: Erland Axelsson, PhD, Karolinska Institutet

Publications and helpful links

General Publications

• Hybelius J, Gustavsson A, Af Winklerfelt Hammarberg S, Toth-Pal E, Johansson R, Ljotsson B, Axelsson E. A unified Internet-delivered exposure treatment for undifferentiated somatic symptom disorder: single-group prospective feasibility trial. Pilot Feasibility Stud. 2022 Jul 19;8(1):149. doi: 10.1186/s40814-022-01105-0.

Study record dates

Study Major Dates

• Study Start (Actual): September 11, 2020
• Primary Completion (Actual): February 24, 2021
• Study Completion (Actual): February 24, 2021

Study Registration Dates

• First Submitted: July 18, 2020
• First Submitted That Met QC Criteria: August 10, 2020
• First Posted (Actual): August 13, 2020

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 13, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: Feasibility; Exposure
• Additional Relevant MeSH Terms: Medically Unexplained Symptoms
• Other Study ID Numbers: 2020-01740

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: We are willing to consider reasonable requests for individual participant data (IPD) and to consult the responsible parties accordingly. However, we do not expect to be granted permission to share IPD as long as, under Swedish and European Union (EU) data protection and privacy legislation, the IPD constitutes personal data meaning that it is possible to, using the study database, link the IPD to an identifiable living natural person.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No