The following text is taken out of the Attention Deficit, 'Hyperactivity Disorder (ADHD) - A Practical Guide for Parents and Carers' publication which is fully available below.
At one time or another, most children show weak concentration, become overactive, or act without thinking. There are some children, however, who show particular and exceptional difficulties with inattention, hyperactivity and impulsivity, which have an effect on their learning and behaviour and which they themselves seem unable to control. These difficulties do not appear to be explained by usual influences such as computer games, too much TV, poor management, diet and so on.
Such children are currently referred to as having Attention Deficit Hyperactivity Disorder (ADHD - sometimes referred to as ADD).
What is ADHD
Children with ADHD show particular difficulties in some or all of the following:
Inattention (e.g. “can’t focus; doesn’t seem to be listening; seems to be daydreaming; very easily distracted; can’t concentrate”.)
Hyperactivity (e.g. “always on the go; can’t sit still.”)
Impulsiveness (e.g. “acts before he thinks; can’t stop himself shouting out or hitting out”.)
Many, or indeed most, children will of course show difficulties in these areas at some time in their lives. The difference for those with ADHD is that these behaviours must:
be present for more than six months;
be severe enough to interfere with the normal progress for children of the same age;
not be explained by developmental level or other difficulty / condition; and
not be explained by other factors such as “laziness”; lack of sleep; too much TV; videos; food additives.