Nature deficit disorder is a phrase coined by Richard Louv in his 2005 book Last Child in the Woods meaning that human beings, especially children, are spending less time outdoors resulting in a wide range of behavioral problems. This disorder is not recognized in any of the medical manuals for mental disorders, such as the ICD-10 or the DSM-5. Evidence was compiled and reviewed in 2009. 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".
Louv claims that causes for the phenomenon include parental fears, restricted access to natural areas, and the lure of the screen. Recent research has drawn a further contrast between the declining number of National Park visits in the United States and increasing consumption of electronic media by children.
The phrase has been criticized as a misdiagnosis that obscures and mistreats the root problems of how and why children do not spend enough time outdoors and in nature.
Richard Louv spent ten years traveling around the US reporting and speaking to parents and children, in both rural and urban areas, about their experiences in nature. He argues that sensationalist media coverage and paranoid parents have literally "scared children straight out of the woods and fields", while promoting a litigious culture of fear that favors "safe" regimented sports over imaginative play.
In recognising these trends, some people argue that humans have an instinctive liking for nature—the biophilia hypothesis—and take steps to spend more time outdoors, for example in outdoor education, or by sending young children to forest kindergartens or forest schools. It is perhaps a coincidence that slow parenting advocates send children into natural environments rather than keeping them indoors, as part of a hands-off approach.
Studies by other researchers throughout the world suggest physical activity and exposure to nature are important to good health, report positive impacts upon mental health and wellbeing associated with natural environments, and can reduce sadness and negative emotions.