Attention deficit hyperactivity disorder, or ADHD, is increasingly being diagnosed in young children, with an estimated 11 per cent of children having the most common symptoms, which include an inability to sit still, pay attention or follow directions. A new study from a collaboration of universities in America has put forward evidence suggesting that a common pesticide may be responsible for increasing the risk of ADHD. Pyrethroid pesticide has been shown to alter the development of the brain’s dopamine system, which is responsible for emotional expression and cognitive function.

It is already recognised that genetics play a key part in a child’s risk of developing ADHD, but the scientists believe modifying environmental factors such as exposure to pesticides may be an important area of research. They note that children and pregnant women may be more susceptible to pesticide exposure, as their bodies cannot remove the chemicals quickly, so damaging effects are more likely.