Researchers find Attention Deficit Hyperactivity Disorder (ADHD) in children from families living below the poverty line and in those who belong to single-parent families.

A team led by the University of Exeter Medical School analysed data of more than 19,500 British children born between 2000 and 2002. The data was recorded when they were nine months old, and again at the age of three, five, seven and 11, respectively. 

The experts found that children affected with ADHD belong to families whose average income was $525 per week when compared to $633 from families of unaffected children.

"There is a genetic element to ADHD, but this study provides strong evidence that ADHD is also associated with a disadvantaged social and economic background. Some people believe that ADHD in children causes disadvantage to the economic situation of their family, but we found no evidence to support that theory," Study leader Dr Ginny Russell, of the University of Exeter Medical School, said in a press release.

"It's important to discover more about the causes of this disorder so that we can look towards prevention, and so that we can target treatment and support effectively."

The findings support studies previously conducted in Northern Europe, the United States and Australia. But this is the first study that has found a link between ADHD and socio-economic status in the U.K.

The symptoms of ADHD include inattentiveness, hyperactivity and impulsiveness. These are normally noticed at an early age and diagnosed between ages three and seven. Around 2 to 5 percent school-aged children are estimated to suffer from ADHD. However, the disorder can also be characterised as a lifelong condition as many children reveal symptoms later in life, Nursing Times reports.

Other findings of the study are:

-          Parents living in social housing were three time more likely to have a child with ADHD when compared to those who owned a house.

-          Younger mothers were at a higher risk of having a child with ADHD than older mothers.

-          Mothers with no qualifications were more than twice likely to have a child with ADHD than those with degrees.

The study has been published in the Journal of Child Psychology and Psychiatry.