Abstract
The lack of highly effective treatments for fibromyalgia (FM) represents a great challenge for public health. The objective of this parallel, pilot randomized controlled trial (RCT) was two-fold: (1) to analyze the clinical effects of mindfulness plus amygdala and insula retraining (MAIR) compared to a structurally equivalent active control group of relaxation therapy (RT) in the treatment of FM; and (2) to evaluate its impact on immune-inflammatory markers and brain-derived neurotrophic factor (BDNF) in serum. A total of 41 FM patients were randomized into two study arms: MAIR (intervention group) and RT (active control group), both as add-ons of treatment as usual. MAIR demonstrated significantly greater reductions in functional impairment, anxiety, and depression, as well as higher improvements in mindfulness, and self-compassion at post-treatment and follow-up, with moderate to large effect sizes. Significant decreases in pain catastrophizing and psychological inflexibility and improvements in clinical severity and health-related quality of life were found at follow-up, but not at post-treatment, showing large effect sizes. The number needed to treat was three based on the criteria of ≥50% Fibromyalgia Impact Questionnaire (FIQ) reduction post-treatment. Compared to RT, the MAIR showed significant decreases in BDNF. No effect of MAIR was observed in immune-inflammatory biomarkers (i.e., TNF-α, IL-6, IL-10, and hs-CRP). In conclusion, these results suggest that MAIR, as an adjuvant of treatment-as-usual (TAU), appears to be effective for the management of FM symptoms and for reducing BDNF levels in serum.