PRL and major depressive disorder: Furthermore, the spa environment can work therapeutically on psychological issues, having a positive action on resilience and depression mediated by an increase in adrenocorticotropic hormone, cortisol, prolactin, growth hormone, and endorphin levels following balneotherapy (Antonelli & Donelli 2018; Fioravanti et al. 2017; Gálvez et al. 2018; Masiero & Maccarone 2021).