Do food additives cause hyperactivity?

This paper covers the results of a study conducted on the Isle of Wight between 1997 and 2000, which looked at the association between food additives and behavioural problems - hyperactivity in particular.
Hyperactivity is actually much more prevalent than one might think and is a commonly diagnosed behavioural disorder, particularly in a primary care setting. The symptoms are varied, and include difficulty in concentrating, an excessive level of activity, and impulsive behaviour. These symptoms are frequently found in young children who may not suffer from the disorder.
Comorbility has been researched, and there is good evidence to suggest that those children who have a diagnosis of hyperactivity and attention deficit hyperactive disorder (ADHD) have difficulties in language development, and in adapting to school life, and academic achievement. In addition, there are many confounding factors, which could influence any investigation of hyperactivity. These could include diet, social class, gender (particularly male) and possible allergy and atopy.