Neuroactive steroids and the new decade

The term ‘neurosteroids’ started to be used in the 1980s to indicate a family of steroids synthesised within the brain and regulating, via steroid receptors or other receptors, several brain functions. Later on, the term ‘neuroactive steroids’ was introduced to include those steroids that are not synthesised in the brain or are only partly me- tabolised (eg, the transformation of testosterone into oestradiol via the action of brain aromatase) but can interact with neural circuits. During the first two decades of the current century, the number of published papers in this field increased by 3620 (source PubMed, keywords neurosteroid* or neuroactive steroid*), demonstrating a continuous interest in this wide topic. Our international congresses, started at the beginning of the century, have covered the entire scope of this broad research field, and contributions to these bien- nial meetings have been published in a series of special issues for different journals. The present special issue includes many of the invited lectures presented during the last edition of the “Steroids and Nervous System” meeting (Torino, February 2019), contributed as contem- porary reviews or as original articles. The papers not only embrace classical themes such as gonadal steroids and glucocorticoids, but also very new topics such as the involvement of neuroactive steroids in the control of energy homeostasis and the development of trans- lational models for a variety of neural diseases in which neuroactive steroids are implicated.