>I suspect too much or too frequent neurogenesis would have a counter productive effect. Well-functioning adults manage their vices. If they don't, it leads to bad effects. In this case, too many/much psychedelics can have an obvious effect seen in many "hippies" and the like. A well-functioning person however may partake once or twice a year and have good benefits from doing so. Properly managing intake goes for *any* drug, including food.