[Neurobiology of depression and stress syndromes. Focus on active neurosteroids and neurosteroids].

That the brain is a target for hormones is a well established fact. Today we also know that brains can secrete the whole gamut of peptides and steroid hormones, i.e., pregnanes and pregnenes. Considering that the ancestral neuron was a neurosecreting cell, this is not surprising. As CRH and cortisol secretion occur in situ in nervous systems, the intriguing possibility that anxio-depressive syndromes may be associated with paracrine effects of these compounds on the brain should now be considered. The concept of stress as a specific reaction of the nueroendocrine system to nocuous stimuli is re-examined in light of new evidence. The fundamental importance of historical, social, and psychological contexts in evaluating hormonal actions is emphasized. Problems emerging from the attempt to search for specific biological markers in different psychiatric disorders are discussed. The suggestion is made that, rather than to categorize nosological entities, biological dysfunctions should be elated with psychological abnormalities.