Most estimates lie between 5% and 10% [4]. US
estimates have historically been higher than UK
estimates, due presumably to the application of narrower
diagnostic criteria by UK authors [5]. Three studies of
English populations have shown a prevalence rate of between
2% and 5%, depending on whether DSM-IV or
ICD-10 criteria were applied [4,6]. ADHD has been
found to not only be prevalent in the West but also in
the Middle East, Africa and Asia [7]. Co-morbid Anxiety
Disorders, Mood Disorders and Substance Misuse are
commonly reported [8,9].