Ed criteria, apparently an everincreasing percentage of the global population, are hardly in optimal mental health. The viewpoint of Dubos was along those very sight lines–less focused around an epidemic of mental disorders per se and more concerned with a future erosion of optimal mental health and humanism. Research certainly suggests that his future is now. Dubos argued that separation from the natural world was eroding humanness and that humanness was centrally defined by altruistic and empathic CPI-455 web behavior. “However, the really human aspect of altruism is not its biological origin or its evolutionary advantages but rather the fact that humankind has now made it a virtue regardless of the practical advantages or disadvantages. Since earliest recorded history, altruism has become one of the absolute values by which humanity transcends animality.” [115]. To be clear, as much as Dubos mentioned Paleolithic and PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/25112874 Stone Age imprints related to modern health, he provided equal time to underscoring the fact that DNA does not determine behavioral destiny. His studies with animals paved the way for behavioral epigenetics. He proved, at least in rodents, that there are adult implications to early-life variables such as maternal grooming, social setting, stress, nutrition, and microbiota contact. “Through complex mechanisms that are only now being recognized, environmental stimuli determine which parts of the genetic endowment are repressed and which parts are activated. In other words, the life experiences determine the extent to which genetic endowment is converted into functional attributes. From nutrition to education, from topography of the land to religious background, countless are the attributes that contribute to shaping the body and the mind of man” [116], [page 153]. Some 30 years later, the discovery of epigenetic changes would explain how early-life experiences can indeed be converted into functional attributes [117]. From a pessimistic perspective, the realization that environmental factors can influence neuropsychiatric risk in offspring beyond a single generation (i.e., they can be trans-generational [118,119]) does not bode well in the context of apparent generational increases inpsychological distress. On the other hand, the mental health implications of epigenetic processes are cause for optimism because evidence indicates that they are modifiable [120,121].Natural environments”Urban dwellers never have the chance to see the Milky Way, or a night radiant with stars, or even a truly blue sky. They never experience the subtle fragrances peculiar to each season; they lose the exhilaration of early spring and the delightful melancholy of autumn. The loss of these experiences is more than an aesthetic affliction; it corresponds to a deprivation of needs which are essential to physical and mental sanity, because they were indelibly woven in man’s fabric during his evolutionary past”. Ren?Dubos in Bailey A [122]. Dubos argued that access to and contact with natural environments was essential to the mental health of populations; therefore, an appropriate starting point is to examine in top-down fashion–i.e., through an epidemiological lens–the recent scientific assessments of the relationship between nature and mental well-being. A variety of population-level studies have provided support to the notion that natural environments are associated with health promotion in urban settings. Studies have linked the perceived degree of greennes.