Pregnenolone is a steroid hormon that is directly produced by the brain as well, that is why it is defined neurosteroid. Pregnenolone carries out several cerebral functions, such as neuroprotection, neuroplasticity and neurogenesis; moreover, it regulates the mood and the memory. All of these functions are possible thanks to the relationships pregnenolone establishes with some of the most important neurotransmitters. As a matter of fact, it connects to GABA receptors, NMDA receptors and sigma-1 receptors. It has been proved that pregnenolone is concerned with some important neurological and psychiatric diseases. Actually, some scientists hypothesize that it could also be useful to these diseases' pharmacotherapy. This article illustrates the ways pregnenolone may be used and the ways it is concerned with neurological and neuropsychiatric diseases.