Children whose schools are lined with trees and close to green space are less likely to have ADHD, a study has found.
Scientists analysed the surrounding environments of the schools of almost 60,000 youngsters in China.
Results showed children were less likely to have attention-deficit hyperactivity disorder if their school was close to green space.
Academics at Guangzhou’s South China Institute of Environmental Sciences believe spending time in nature stimulates the brains of youngsters.
Theories say humans are ‘innately attracted’ to nature and need it while young for the development of crucial brain structures.
The team of researchers, led by Dr Bo-Yi Yang, called for further trials to explore why nature can stave off ADHD.
But they also called for more trees to be planted outside schools.
Children in greener areas are less likely to have ADHD, a study in China has found (stock)
Around five per cent of children in the UK and US are believed to have ADHD. It causes children to be disruptive and struggle to concentrate.
Symptoms of the condition include constant fidgeting, an inability to listen, poor concentration and excessive talking.
The research, published in JAMA Network Open, asked parents of 59,745 children aged two to 17 to complete a survey to measure ADHD symptoms.
Parents were asked how often their children had shown 18 different symptoms of ADHD in the past six months, whether that be never, sometimes, often or very often.
Nature around the schools was measured by satellite image-derived databases that can quantify a level of greenery on a scale.
Of the 59,754 children included in the analysis, 2,566 (4.3 per cent) were identified as having ADHD because they had at least six symptoms.
This was not confirmed with a clinical diagnosis, which the researchers admitted was a limitation of the study.
Children with ADHD were more likely to be boys over the age of seven, born preterm, or whose mothers were cigarette smokers or alcohol drinkers.
As they theorised, scientists found children with ADHD symptoms attended schools with lower levels of greenery.
Greenery was measure on a scale of -1 to 1, with -1 normally representing water, 0 representing rock, and 1 representing dense leaves and greenery.
Every 0.1 unit increase in greenery within 500m of a school lowered the odds of ADHD symptoms by up to 20 per cent.
The researchers wrote: ‘We observed higher greenness exposure was significantly associated with lower odds of ADHD symptoms.
‘Given attention is a critical prerequisite for learning, greenness in school settings may be of great public health significance.
The academics, writing in their scientific paper, added: ‘Our findings, therefore, are relevant to policy makers and health care authorities.’
A casual link between green space and ADHD cannot be made yet – but several mechanisms may explain the link.
Trees and plants can reduce levels of air pollution, which is proven to harm brain development.
Brain development is believed to play a role in the development of ADHD, along with a number of factor such as genetics.
A number of differences in the brains of people with ADHD have been identified in previous research.
For example, studies involving brain scans have suggested that certain areas of the brain may be smaller in people with ADHD, whereas other areas may be larger.
There is a theory, called biophilia hypothesis, which says humans are innately attracted to nature, and therefore exposure is beneficial for the development of a child’s brain.
A 2018 study of schoolchildren provided strong evidence for this, finding that high levels of exposure to green space was linked with better volume of certain brain regions.
These areas of the brain are involved with attentiveness and working memory, the researchers from Barcelona wrote in the journal Environmental Health Perspectives.
WHAT IS ADHD AND ITS SYMPTOMS?
Attention deficit hyperactivity disorder (ADHD) is an incurable behavioural condition defined by inattentiveness, hyperactivity and impulsiveness.
It affects around five per cent of children in the US, and some 3.6 per cent of boys and 0.85 per cent of girls in the UK.
A combination of medication and therapy is usually recommended to relieve symptoms as children can struggle to focus and adults can often have difficulty organising or balancing life.
Symptoms typically appear at an early age and become more noticeable as a child grows, the NHS says. Most cases are diagnosed between six and 12 years old. Adults can also suffer, but there is less research into this.
- Constant fidgeting
- Poor concentration
- Excessive movement or talking
- Acting without thinking
- Little or no sense of danger
- Careless mistakes
- Difficulty organising tasks
- Inability to listen or carry out instructions
ADHD’s exact cause is unclear but is thought to involve genetic mutations that affect a person’s brain function and structure.
Premature babies and those with epilepsy or brain damage are more at risk.
ADHD is also linked to anxiety, depression, insomnia, Tourette’s and epilepsy.