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.

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.

Systematic confrontation with stimuli associated with symptom-related distress, to achieve therapeutic changes in cognitions or behavior

Primarily according to the Patient Health Questionnaire-15 (PHQ-15, theoretical range: 0-30, higher score indicates more distressing physical symptoms)

Feasibility 3: adherence to the protocol in terms of at least 60% completed modules and at least 50% of participants completing at least 2 exposure exercises

Feasibility 4: patient-reported adequacy of rationale as assessed using a questionnaire developed specifically for this purpose (theoretical range: 0-10)

Was originally intended to be administered at week 3, but was administered post-treatment due to an administrative error

Feasibility 5: adequacy of the measurement strategy in terms of less than 30% missing data at post-treatment, and at least 75% finding the measurement strategy acceptable

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. The original preregistered range of 7-28 was an erratum.

Feasibility 7a: adverse events measured using free-text items, primarily reported as the total number of reported events

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

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

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

Screening, pre-treatment assessment (within 2 weeks before treatment), Post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment

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

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

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

Screening, pre-treatment assessment (within 2 weeks before treatment), post-treatment assessment (immediately after treatment, completed within 45 days), 3 months after treatment

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

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.

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.