Attention deficit hyperactivity disorder (ADHD) may be brought on by experiencing stress in infancy, claims a leading parenting expert.

According to psychologist, parent educator and author of the best-selling Raising Boys, Steve Biddulph, new research suggests factors such as “stress at home and parents not meeting children’s needs early in life” could play a role in causing ADHD.

Previously it was thought that the behavioural disorder - typically characterised by inattentiveness, hyperactivity and impulsiveness - was caused by genetics and chemical imbalances in the brain.

But in the new, updated version of Raising Boys, Biddulph highlights new studies which suggest stress in infancy plays a role in the development of ADHD.

Around one in 20 boys in the UK are diagnosed with ADHD, most often when aged between six and 12 years old.

Girls do suffer from ADHD too, but the symptoms are often harder to spot - it’s more common for girls with ADHD to be “daydreamers” rather than “trouble-makers,” according to Patricia Quinn, MD, co-author of Understanding Girls with ADHD.

Symptoms tend to improve as children age, but some people continue to experience problems into adult life.

Biddulph says that some cases of ADHD could actually be called DDD - “Dad Deficit Disorder.” The author has in the past been vocal about the importance he places on fathers being involved in their sons’ lives and teaching them self-control.

In the new version of Raising Boys, Biddulph highlights the work of Dr Gabor Maté, who believes that: “Rather than an inherited disease, Attention Deficit Disorder is a reversible impairment and a developmental delay, with origins in infancy.

“It is rooted in multigenerational family stress and in disturbed social conditions in a stressed society.”

Both Maté and Biddulph believe that the part of the brain which allows us to feel calm develops in the second six months of life.

“Reducing stress on mothers and ensuring good attachment during the age of six months to one year may be crucial to preventing ADHD in vulnerable children,” writes Biddulph.

“ADHD is real… but it’s also often overdiagnosed. It’s important to look at all possible causes - what might be stressing the child in his home, school or other locations.”

Children with ADHD are often given medication such as Ritalin, which has amphetamine-like effects, but Biddulph says he does not think this is the right approach to take.