About 5.4 million American children, aged from 4 to 17 years, have some form of ADHD, according to the latest figures. This represents a 21 per cent increase over a four-year period.
The current levels could be even worse as these figures represent the situation in 2007, when the survey was carried out. If the trend has continued, 6.48 million American children have ADHD today.
The increase has happened across all socio-demographic groups, and especially among older teenagers, who have witnessed a 42 per cent rise.
Researchers from the US's Centers for Disease Control and Prevention surveyed parents, who were asked if a doctor or healthcare provider had diagnosed ADHD in their child.
(Source: Morbidity and Mortality Weekly, 2010; 59: 1439-43).