Depression is the second major cause of disability worldwide
affecting around 350 million people (WHO, 2009). Although the
precise etiology of depression is complex and remains unclear,
there is evidence that the prevalence of depressive disorder
increases with age (Samaras et al., 2013) and affects around 17%
of the elderly population (Luppa et al., 2010).
Dehydroepiandrosterone (DHEA) is a steroid hormone mainly
synthesized in the adrenal glands in response to adrenocorticotrophic
hormone, although de novo synthesis in the brain has also
been described (Maninger et al., 2009; Sugaya et al., 2015). DHEA
and its sulphated form DHEA(S) are the more prevalent circulating
steroid hormones, acting as precursors of the sexual hormones, as
a neurosteroid, and it is hypothesised to present opposite effects to