Nature deficit disorder refers to the phrase coined by Richard Louv in his 2005 book Last Child in the Woods [1] that human beings, especially children, are spending less time outdoors [2] resulting in a wide range of behavioral problems.[3][4] This disorder is not recognized in any of the medical manuals for mental disorders, such as the ICD-10[5] or the DSM-5.[6] Evidence was compiled and reviewed in 2009.[7] Richard Louv has stated "nature-deficit disorder is not meant to be a medical diagnosis but rather to serve as a description of the human costs of alienation from the natural world."[citation needed]

Louv claims that causes for the phenomenon include parental fears, restricted access to natural areas, and the lure of the screen.[8]