Exposure-based Cognitive Behavior Therapy vs Traditional Cognitive Behavior Therapy for Fibromyalgia

Fibromyalgia (FM) is a common medical condition characterized by chronic generalized musculoskeletal pain, fatigue, and a series of additional somatic and psychiatric problems that give rise to distress, functional impairment, and substantial societal costs. The most extensively evaluated treatment for FM is traditional cognitive behavior therapy (T-CBT) which typically appears to have small to moderate effects when compared to waitlist, attention control, treatment as usual or other active nonpharmacological therapies. Internet-delivered exposure-based cognitive behavior therapy (Exp-CBT) where the patient willingly and systematically engages with stimuli associated with pain and pain-related distress has shown promising controlled effects versus a waiting-list but has never been compared to T-CBT in a randomized controlled trial. In this randomized controlled trial, self-recruited adults with FM (N=260) are randomly assigned (1:1) to 10 weeks of internet-delivered Exp-CBT or internet-delivered T-CBT and complete self-report questionnaires to measure symptoms and therapeutic processes up to 12 months after treatment. Primary outcome is the relative effect of Exp-CBT and T-CBT on FM severity as modelled using linear mixed models fitted on weekly Fibromyalgia Impact Questionnaire sum scores over the treatment period, testing the hypothesis of Exp-CBT superiority based on the coefficient for the time × group interaction. The investigators will also calculate the number of treatment completers in each treatment condition, defined as having commenced module five out of eight treatment modules. Cost-effectiveness and mediational processes are investigated in secondary analyses. The investigators expect this trial to be of notable clinical significance as it will provide valuable information about the value of Exp-CBT in helping patients with FM as compared to using other interventions.

FM is a common problem with substantial negative consequences. The most widely evaluated psychological treatment for FM is T-CBT which usually has small to moderate controlled effects on pain, mood and functional impairment. Based on one pilot study and one wailist-controlled RCT, Exp-CBT appears to have promising effects on FM but this treatment has not yet been compared to an active control condition. The present study aims to compare internet-delivered Exp-CBT to internet-delivered T-CBT in a randomized controlled trial.

Participants in Exp-CBT and T-CBT are encouraged to work with self-help texts and complete regular homework exercises via a secure treatment platform. Both treatments are 10 weeks long, equally exhaustive, and involve approximately the same level of therapist support.

Primary outcome is the relative effect of Exp-CBT and T-CBT on FM severity as modelled using linear mixed models fitted on weekly Fibromyalgia Impact Questionnaire sum scores over the treatment period, testing the hypothesis of Exp-CBT superiority based on the coefficient for the time × group interaction. The investigators will also calculate the number of treatment completers in each treatment condition, defined as having commenced module five out of eight treatment modules. Detailed information regarding analysis of clinical efficacy is provided in the supplementary file.

In addition to clinical efficacy, the investigators will also investigate cost-effectiveness and mediational processes. The primary hypothesis is that Exp-CBT is significantly more efficacious than T-CBT in reducing FM severity, i.e., the Fibromyalgia Impact Questionnaire (FIQ) composite score indicative of symptoms and functional status, from the baseline assessment to the 10-week assessment.

Eligibility Criteria:
Inclusion Criteria:

* Living in Sweden
* Access to the internet
* Completed pre-treatment assessment
* If on psychotropic medication, dose kept stable for at least 4 weeks before randomization and the participant agrees to keep it constant during treatment

Exclusion Criteria:

* Severe depression (≥ 30 on the Montgomery Åsberg Depression Rating Scale-Self Rated \[MADRS-S\] at screening)
* Suicidal ideation (≥ 4 on the suicide item of the MADRS-S at screening),
* Psychosis
* Alcohol or substance use disorder as primary diagnosis or likely to severely interfere with treatment
* Ongoing psychological treatment
* Pregnancy (\>29 wk gestation)
* Another somatic condition that requires immediate treatment and/or is deemed to be the primary condition
* Insufficient knowledge of the Swedish language or insufficient computer skills to benefit from the text-based online treatment.