Internet-based Exposure-based Therapy for Fibromyalgia: A Randomized Controlled Trial.

Trial Objectives: Primary objective is to investigate whether an Internet-based exposure therapy can effectively reduce the degree of Fibromyalgia symptoms and impact. Secondary objectives are to 1) investigate the treatment's ability to reduce degree of a) quality of life b) function c) insomnia and fatigue d) pain-related fear and negative thoughts e) depression and anxiety, cost-effectiveness of this treatment; and 2) to study if any variables could moderate/mediate the treatment outcome, such as a) degree of covert avoidance, b) degree of reactivity to inner sensations

Trial Design: Randomized controlled trial with waitlist control, who also will receive treatment after the first group has finished.

Duration: Ten weeks

Primary Endpoint: Change in Fibromyalgia symptoms and impact from baseline to Week 10. Long term follow-up is also investigated (potential changes from post-treatment to 6- and 12 months after treatment completion)

Efficacy Parameters: the Fibromyalgia Impact Questionnaire (FIQ)

Description of Trial Subjects: Patients > 18 years old, Fibromyalgia diagnosis, residing in Sweden.

Number of Subjects: 140

Sample size estimation: Sample size is based on a estimated effect size (measured by Cohen's d) of 0.5, based on a power of 0.8 and with room for a 10 % dropout rate.

Recruitment: Self-referral. Advertising will be made through national newspaper, social media and on patient organisations' websites.

Safety parameters: Participants will have the opportunity to report any adverse events during treatment at posttreatment and follow-up measurements.

Data collection: Data will be collected electronically via the treatment platform.

Plan for missing data: Last-observation carried forward (LOCF).

Main statistical analysis: Hierarchical linear mixed modelling.

Inclusion criteria

• Fibromyalgia diagnosis
• Swedish resident
• Internet connection before, under and after treatment
• Willing to refrain from other concurrent psychological treatment during the study
• Agreement to keep psychotrophic medication constant during the study

Exclusion criteria

• Severe depression (≥30 points on Montgomery Åsberg Depression Rating Scale - Self Rated (MADRS-S) or risk of suicide (≥4 points on the suicide item on MADRS-S)
• Ongoing alcohol or substance abuse
• Psychosis
• Other severe illness that require immediate treatment and/or was considered the participants primary concern other than FM, or bodily condition that makes treatment unfeasible (such as late pregnancy; >29 weeks gestation
• Illiteracy or poor skills in Swedish language
• Insufficient computer or language skills to manage a text-based treatment.
• Other concurrent psychological treatment
• Recent changes in psychotrophic medication (<6 weeks prior to randomization)