BDNF and fibromyalgia: In fibromyalgia, clinical studies that exclusively enrol women tend to report elevated BDNF levels (Behnoush et al. 2023) and find positive correlations between serum BDNF levels, increased motor cortex excitability disinhibition and enhanced function of the descending pain modulation system in affected women (Caumo et al. 2016) However, studies that include both men and women more often have observed a lack of elevated BDNF levels in fibromyalgia patients (Baumeister et al. 2019; Dimmek et al. 2021) suggesting potential sex differences in BDNF regulation.