Fibromyalgia (FM) is frequently comorbid with major depressive disorder (MDD), yet the biological heterogeneity of depression in FM is not well defined. This study evaluated whether melancholic and atypical depressive subtypes occur in FM and differ in hypothalamic–pituitary–adrenal (HPA) and growth hormone (GH) axis function. In a cross‑sectional sample of FM patients with and without depression, depressive subtypes were clinically identified and endocrine function assessed using dexamethasone and combined dexamethasone/CRH tests, along with plasma IGF‑1 levels. Atypical depression was more prevalent, while melancholic depression was associated with increased HPA axis activation. No differences in IGF‑1 levels were observed.
