1. Beyond its antidiuretic and vasopressor effects, vasopressin has central nervous system effects, first described in rats by David de Wied in 1965. 2. Its first clinical use in humans, in 1978, confirmed its stimulant action in normal individuals, especially in middle-aged male subjects. 3. Its utility in mnemic problems is also worht considering when the pathology is relatively recent (less than 2 years prior) and unaccompanied by major neurological lesions. Behavioral modifications, such as improvement of "sociability", "mood" improvement, independent of its effects on memory have been described, and would justify complementary clinical investigation. 4. New synthetic vasopressin derivatives which would eliminate metabolic effects while maintaining behavioral effects intact, and the definition of clinical, neuroendocrine, and neurophysiological prognostic criteria, will be the two most important paths for investigation over the next years.