Attention deficit hyperactivity disorder (ADHD) is a behavioural disorder that affects the behaviour or development of young children. Children suffering from ADHD show signs of inattention, overactivity or impulsiveness. Many children with ADHD cannot explain why they might feel lonely or out of control.
The normal attention span of children usually develops in 3 stages. They begin from fixating on only one object for a long time to developing a wide and quick attention span, and finally they reach the selective attention stage where they are able to voluntarily shift their focus. The last stage is important for the child to work in a classroom setting. ADHD is more common in boys than girls. Children with ADHD start to develop symptoms before they turn 7 years old.