An interventional study of Planned, systematic, exposure exercises and Response prevention in Psychological Factors Affecting Other Medical Conditions, Somatic Symptom and Related Disorders and Bodily Distress Disorder, sponsored by Region Stockholm. Not yet recruiting at 1 site in Sweden. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-11.
Sponsored by Region Stockholm · Not applicable, Interventional, and Treatment
It is unclear to what degree systematic exposure exercises contribute to the overall effects of exposure therapy (exposure and response prevention). This trial recruits individuals with high somatic symptom burden or reactivity to symptoms who, based on previous work, are likely to benefit specifically from exposure therapy. The aim of the study is to evaluate to what degree the effect of exposure therapy for this group is driven by the addition of structured exposure exercises to response prevention. This will be evaluated on the basis of a randomized controlled trial (N=360) where participants are enrolled either in response prevention (n=180), or exposure and response prevention (n=180). Primary outcome will be the between-group differences in the reduction in reactivity to symptoms, as measured week-by-week using the somatic symptom disorder B-criteria scale (SSD-12). Results from this project will be informative for exposure-based and various multicomponent behavioral treatments for individuals with persistent physical symptoms worldwide.
Persistent physical symptoms refers to somatic complaints that persist for months or more and give rise to significant distress, regardless of etiology. Common complaints such as gastrointestinal symptoms, fatigue, and pain have been estimated to account for up to half of primary care consultations, can be difficult to classify, and often defy straightforward medical explanation. In light of substantial personal and socioeconomic repercussions, effective clinical interventions are needed. The investigators recently completed a randomized controlled trial in primary care (SOMEX1) where individuals with persistent physical symptoms were randomized to 10 weeks of exposure therapy or healthy lifestyle promotion. Based on that trial, exposure therapy appears to have a small average advantage over healthy lifestyle promotion in mean effect on symptom preoccupation, i.e., the patient's tendency to respond strongly to, and engage in behaviors contingent on, somatic symptoms, and also on patient satisfaction. In line with a priori hypotheses, this added effect on symptom preoccupation was larger, and an advantage in the effect on somatic symptom burden was also seen, when patients reported a very high general somatic symptom burden or symptom preoccupation before treatment. For example, a patient with a PHQ-15 score of 10 could expect a near-zero added effect of exposure therapy on somatic symptom burden (d = 0.08) and a small added effect on symptom preoccupation (d = 0.31), whereas a patient with a PHQ-15 score of 15 could expect a small to moderate added effect on somatic symptom burden (d = 0.37) and a moderate added effect on symptom preoccupation (d = 0.62). An unexpected finding, however, was that in exposure therapy, the correlation between the participant's number of exposure exercises and reduction in symptom preoccupation was weak (rs=0.21-0.26). This highlights the fact that it is yet unclear to what degree the two main components of exposure therapy - exposure and response prevention - contribute to the treatment effects. It is also unclear what patient- and contextual factors moderate the added effect of exposure.
The aim of the present project is to focus on the aforementioned subgroup of patients who benefit specifically from exposure therapy, and to determine to what degree this is driven by the addition of exposure to response prevention. This will be evaluated on the basis of a randomized controlled trial (N=360; SOMEX2) where participants with a high general somatic symptom burden or high symptom preoccupation are enrolled in response prevention (n=180), or exposure and response prevention (n=180). Primary outcome will be between-group differences in the reduction in symptom preoccupation as measured week-by-week using the somatic symptom disorder B-criteria scale (SSD-12). The participants will be blinded to the study design and the hypotheses of the investigators. Results from this project will be informative for exposure-based and various multicomponent behavioral treatments for primary care patients with persistent physical symptoms worldwide.
- Primary research question:
Is there a significant average advantage, d≥0.30, of exposure and response prevention, as compared to response prevention only, with regard to the reduction in symptom preoccupation (SSD-12) up to the post-treatment assessment? Hypothesis: Yes.
- Key secondary research questions:
Is the average advantage of adding exposure to response prevention moderated by the frequency of opportunities for response prevention as measured at baseline? Hypothesis: Yes, more opportunities are predictive of a smaller added effect of exposure exercises.
Is the average advantage of adding exposure to response prevention moderated by the temporality of unwanted outcomes as measured at baseline? Hypothesis: Yes, more distal unwanted outcomes are predictive of a larger added effect of exposure exercises.
Is the average advantage of adding exposure to response prevention moderated by anxiety sensitivity - i.e., reactivity to physiological arousal - at baseline? Hypothesis: Yes, a higher anxiety sensitivity is predictive of a larger added effect of exposure exercises.
Which additional variables act as moderators and mediators of added effects (below)?
Are there average advantages of adding exposure (superiority, ds≥0.30) with regard to general somatic symptom burden, core depressive symptoms, or functional impairment? Hypothesis: No.
What is the cost-effectiveness of exposure and response prevention versus response prevention? Exploratory analyses.
71 studies on the registry are indexed under Medically Unexplained Symptoms; 22 are open to participants now.
This study's planned enrollment of 360 is above the median of 68 across 53 interventional studies indexed under Medically Unexplained Symptoms.
Browse Medically Unexplained Symptoms studies →Region Stockholm is the lead sponsor of 121 studies on the registry; 69 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Full exposure therapy, i.e., exposure with response prevention.
Behavioral: Planned, systematic, exposure exercises · Behavioral: Response prevention
Response prevention without conventional, planned, exposure exercises.
Behavioral: Response prevention
Exposure exercises, planned on the basis of functional analysis. Participants are encouraged to evaluate the relevance of-, and if so work continuously with-, interceptive, in vivo, and imaginal exposure exercises which are planned at specific timepoints.
Response prevention, planned on the basis of functional analysis. Participants make a plan to reduce presumably negatively reinforced behavior contingent on somatic symptoms and distress related to somatic symptoms.
Somatic Symptom Disorder-B Criteria Scale (SSD-12)
Theoretical range: 0-48. A higher score indicates higher degree of reactivity to symptoms.
Time frame: Change over the main phase, as modeled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment). Additional analyses incorporate 6- and 12-months follow-up assessments.
Somatic Symptom Scale 8 (SSS-8)
Theoretical range: 0-32. A higher score indicates a higher subjective somatic symptom burden.
Time frame: Change over the main phase, as modeled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment). Secondary analyses incorporate 6- and 12-months follow-up assessments.
GAD-7
Theoretical range: 0-21. A higher score indicates more general anxiety.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment). Additional analyses incorporate 6- and 12-months follow-up assessments.
Patient Health Questionnaire 9 (PHQ-9)
Theoretical range: 0-27. A higher score indicates more symptoms of depression.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment). Additional analyses incorporate 6- and 12-months follow-up assessments.
12-item WHO Disability Assessment Schedule 2.0 (WHODAS 2.0)
Theoretical range: 0-100. A higher score indicates more disability.
Time frame: Change over the main phase, as modeled using data from the baseline assessment and primary endpoint (≤45 days after treatment). Additional analyses incorporate 6- and 12-months follow-up assessments.
Seven questions probing into basic emotions related to somatic symptoms
For each emotion (anger, disgust, fear, joy, sadness, shame, surprise), theoretical range: 0-10. A higher score indicates presence of emotion.
Time frame: Change over the main phase, as modeled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
14-item Health Anxiety Inventory (HAI-14)
Theoretical range: 0-42. A higher score indicates more health anxiety.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
Adapted 11-item version of the Catastrophizing about Asthma Scale (CAS)
Domain-specific outcome, for participants with a mean score of at least 1 on the PHQ-15 cardiopulmonary domain. Theoretical range: 0-44. A higher score indicates more reactivity to cardiopulmonary symptoms.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
Reactivity to fatigue (study-specific)
Domain-specific outcome, for participants with a mean score of at least 1 on the PHQ-15 fatigue domain. Theoretical range: not yet finalized. A higher score indicates more reactivity to fatigue.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
Visceral Sensitivity Index (VSI)
Domain-specific outcome, for participants with a mean score of at least 1 on the PHQ-15 gastrointestinal domain. Theoretical range: 0-75. A higher score indicates reactivity to gastrointestinal symptoms
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
Pain Catastrophizing Scale (PCS)
Domain-specific outcome, for participants with a mean score of at least 1 on the PHQ-15 pain domain. Theoretical range: 0-52. A higher score indicates more reactivity to pain.
Time frame: Change over the main phase, as modelled using data from the baseline assessment and primary endpoint (≤45 days after treatment).
Credibility/Expectancy scale (C/E scale)
Theoretical range: 0-50. A higher score indicates higher credibility/expectancy.
Time frame: Week 2 of main phase
Working Alliance Inventory (WAI)
Theoretical range: 6-42. A higher score indicates better relationship with the therapist.
Time frame: Week 2 of main phase
Client Satisfaction Questionnaire (CSQ-8)
Theoretical range: 8-32. A higher score indicates higher satisfaction with treatment.
Time frame: Primary endpoint assessment (≤45 days after treatment)
Negative Effects Questionnaire 20 (NEQ-20)
Scored as percentage scores over the following domains: increase in symptoms (range: 0-100), perceived insufficient quality of treatment (range: 0-100), dependency (range: 0-100), stigma (range: 0-100), and hopelessness (range: 0-100). Higher scores indicate more negative effects.
Time frame: Primary endpoint assessment (≤45 days after treatment)
Reactivity to Symptoms Questionnaire (RESQ; preliminary scale)
Process measure. Under development. Tentatively: avoidance (range: 0-10), information-seeking (range: 0-10), intolerance of inner experience (range: 0-10), prevention/management (range: 0-10). A higher score indicates more reactivity to symptoms.
Time frame: Change over the main phase, as modelled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment).
Cognitive Behavioural Responses to Symptoms Questionnaire (CBRQ)
Process measure. Tentatively: fear avoidance (0-36), damage beliefs (0-20), catastrophizing (0-28), symptom focusing (0-20), embarrassment avoidance (0-16), avoidance/resting behavior (0-20), all-or-nothing behavior (0-20). A higher score indicates higher degree of reactivity to symptoms.
Time frame: Change over the main phase, baseline assessment to the primary endpoint (≤45 days after treatment).
Difficulties in Emotion Regulation Scale (DERS-16)
Process measure. Theoretical range: 16-80. A higher score indicates higher degree of difficulties in emotion regulation.
Time frame: Change over the main phase, baseline assessment to the primary endpoint (≤45 days after treatment).
Behavioral Activation for Depression Scale - 3-item Activation subscale (BADS-AC-3)
Process measure. Theoretical range: 0-18. A higher score indicates higher degree of behavioral activation.
Time frame: Change over the main phase, as modelled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment).
Godin-Shephard Leisure-Time Physical Activity Questionnaire (GSLTPAQ)
Process measure. Theoretical range: 0-infinity. A higher score indicates higher degree of physical activity.
Time frame: Change over the main phase, as modelled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment).
Anxiety Sensitivity Inventory (ASI)
Process measure. Theoretical range: 0-64. A higher score indicates higher degree of anxiety sensitivity.
Time frame: Change over the main phase, as modelled using data from all 11 assessments from the baseline assessment to the primary endpoint (≤45 days after treatment).
EuroQol 5D (EQ-5D)
Used for health economic evaluations. Theoretical range: 0-1, i.e., scored as utility for the purpose of calculating quality-adjusted life years. A higher utility score indicates a higher health-related quality of life.
Time frame: Change modeled from the baseline assessment to 12-months follow-up.
Trimbos Institute and Institute of Medical Technology Questionnaire for Costs Associated with Psychiatric Illness (TIC-P)
Used for health economic evaluations. This instrument is scored in terms of resource use (0-infinity) for the purpose of calculating societal, including healthcare, costs.
Time frame: Change modeled from the baseline assessment to 12-months follow-up.
Patient Health Questionnaire-15 (PHQ-15)
Theoretical range: 0-30. A higher score indicates a higher subjective somatic symptom burden.
Time frame: Screening only.
Alcohol Use Disorders Identification Test (AUDIT)
Theoretical range: 0-40. A higher score indicates more problematic alcohol use.
Time frame: Screening only.
Drug Use Disorders Identification Test (DUDIT)
Theoretical range: 0-44. A higher score indicates more problematic substance use.
Time frame: Screening only.
Plan to share: No — We are willing to consider reasonable requests for individual participant data (IPD) and to consult the responsible parties. 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 existing study database, link the IPD to an identifiable living natural person. Ten years after the last publication, the information necessary for individuals to be identified will be deleted and documentation from the trial will be archived for long-term storage. We expect to include anonymized IPD in this archive. It is our understanding that, under EU law, IPD without the existence of information necessary for individuals to be identified does not constitute personal because the IPD can no longer be linked to a living natural person. Thus, 10 years after the last publication and onwards, we expect to be able to share IPD on request.
This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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