POMC and fibromyalgia: In literature, it has been shown that in MSDs with a psychological component, such as fibromyalgia, spa interventions could positively influence anxiety and mood states (Branco et al. 2016; Fraioli et al. 2013; Maccarone et al. 2020), probably through an increase in cortisol levels, thanks to a rise in ACTH production (Antonelli et al. 2018, Latorre-Román et al. 2015).