Nature deficit disorder
Nature deficit disorder refers to a hypothesis by Richard Louv in his 2005 book Last Child in the Woods  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-IV, neither is it part of the proposed revision of this manual, the DSM-V. Evidence was compiled and reviewed in 2009. 
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.
Richard Louv spent ten years traveling around the USA 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 sending children into natural environments rather than keeping them indoors, as part of a hands-off approach.
Nature is not only to be found in National Parks. The chapter "Eden in a Vacant Lot" by Robert M. Pyle (page 305) emphasises the opportunity for exploration and fascination in small untended wildernesses, and rejoices in the 30,000 vacant lots in Detroit, arising due to down-town decay.
- Parents are keeping children indoors in order to keep them safe from danger. Richard Louv believes we may be protecting children to such an extent that it has become a problem and disrupts the child's ability to connect to nature. The parent’s growing fear of "stranger danger" that is heavily fueled by the media, keeps children indoors and on the computer rather than outdoors exploring. Louv believes this may be the leading cause in Nature Deficit Disorder, as parents have a large amount of control and influence in their children's lives.
- Loss of natural surroundings in a child's neighborhood and city. Many parks and nature preserves have restricted access and "do not walk off the trail" signs. Environmentalists and educators add to the restriction telling children "look don't touch". While they are protecting the natural environment Louv questions the cost of that protection on our children's relationship with nature.
- Increased draw to spend more time inside. With the advent of the computer, video games and television children have more and more reasons to stay inside - the average American child spends 44 hours a week with electronic media.
- Children have limited respect for their immediate natural surroundings. Louv says the effects of nature deficit disorder on our children will be an even bigger problem in the future. "An increasing pace in the last three decades, approximately, of a rapid disengagement between children and direct experiences in nature… has profound implications, not only for the health of future generations but for the health of the Earth itself." The effects from Nature Deficit Disorder could lead to the first generation being at risk of having a shorter lifespan then their parents.
- Attention disorders and depression may develop. "It's a problem because kids who don't get nature-time seem more prone to anxiety, depression and attention-deficit problems." Louv suggests that going outside and being in the quiet and calm can help greatly. According to a University of Illinois study, interaction with nature has proven to reduce symptoms of ADD in children. According to research, "Overall, our findings indicate that exposure to ordinary natural settings in the course of common after-school and weekend activities may be widely effective in reducing attention deficit symptoms in children."  Attention Restoration Theory develops this idea further, both in short term restoration of one's abilities, and the long term ability to cope with stress and adversity.
- Following the development of ADD and mood disorders, lower grades in school also seem to be related to NDD. Louv claims that "studies of students in California and nationwide show that schools that use outdoor classrooms and other forms of experiential education produce significant student gains in social studies, science, language arts, and math".
- Childhood obesity has become a growing problem. About 9 million children (ages 6–19) are overweight or obese. The Institute of Medicine claims that over the past 30 years, childhood obesity has more than doubled for adolescents and more than tripled for children aged 6–11.
- In an interview on Public School Insight, Louv stated some positive effects of treating Nature Deficit Disorder, "everything from a positive effect on the attention span to stress reduction to creativity, cognitive development, and their sense of wonder and connection to the earth."
The No Child Left Inside Coalition works to get children outside and actively learning. They hope to address the problem of nature deficit disorder. They are now working on the No Child Left Inside Act, which would increase environmental education in schools. The coalition claims the problem of nature deficit disorder could be helped by "igniting student's interest in the outdoors" and encouraging them to explore the natural world in their own lives.
In Colombia, OpEPA (Organización para la Educación y Protección Ambiental - ) has been addressing the issue for over 10 years. OpEPA's mission is to reconnect children and youth to the Earth so they can act with environmental responsibility. OpEPA works by linking three levels of education: intellectual, experiencial and emotional/spiritual.
Further reading 
- Louv, Richard. (2011) The Nature Principle: Human Restoration and the End of Nature-Deficit Disorder. Algonquin Books. 303pp.
- Louv, Richard. (2005) Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder (Paperback edition). Algonquin Books. 335pp.
- Louv, Richard, Web of Life: Weaving the Values That Sustain Us.
- For more children, less time for outdoor play: Busy schedules, less open space, more safety fears, and lure of the Web keep kids inside by Marilyn Gardner, The Christian Science Monitor, June 29, 2006
- U.S. children and teens spend more time on academics by Diane Swanbrow, The University Record Online, The University of Michigan.
- 10 Reasons Kids Need Fresh Air by Kevin Coyle, National Wildlife Magazine
- Are your kids really spending enough time outdoors? Getting up close with nature opens a child's eyes to the wonders of the world, with a bounty of health benefits. by Tammie Burak, Canadian Living.
- Stiffler, Lisa (January 6, 2007). "Parents worry about 'nature-deficit disorder' in kids". Seattle Post-Intelligencer
- "Is There Anybody Out There?". Conservation 8 (2). April–June 2007
- Kellert, Stephen R. (ed.) (1993). The Biophilia Hypothesis. Island Press. ISBN 1-55963-147-3.
- Hodgkinson, Tom (2009). The Idle Parent: Why Less Means More When Raising Kids. Hamish Hamilton. p. 233. ISBN 978-0-241-14373-5.
- Kahn, Peter; Kellert, Stephen (2002). Children and nature: psychological, sociocultural, and evolutionary investigations. MIT Press. ISBN 0-262-11267-1.
- Outside Agitators by Bill O'Driscoll, Pittsburgh City Paper
- Last Child In The Woods Interview by Claus von Zastrow, Public School Insights
-  National Environmental Education Foundation
-  By Jim Barlow, News Bureau
-  By Richard Louv, Orion Magazine
- Nature Deficit Disorder,[dead link] No Child Left Inside
- Richard Louv's website
- Children & Nature Network
- Nature Rocks, initiative by Richard Louv and Children & Nature Network to inspire and empower parents to connect children to nature
- NWF's Green Hour website
- An interview with Richard Louv about the need to get kids out into nature, by David Roberts, The Grist: Environmental News and Commentary, 30 Mar 2006.
- Saving kids from nature-deficit disorder - May 25, 2005, NPR
- Public School Insights' Interview with Richard Louv - April 22, 2008
- Chicago Wilderness Leave No Child Inside Initiative
- Planet Ark's Research Report on Children & Nature in Australia