The authors recommend that this hypothesis should to be tested by randomized controlled trials using environmental triggers and immunologic/genetic research.
ADHD as a (non) allergic hypersensitivity disorder: A hypothesis. Lidy M. J. Pelsser 1,2 , Jan K. Buitelaar 3 and Huub F. J. Savelkoul 2. Pediatric Allergy and Immunology, 10.1111/j.1399-3038.2008.00749.x
Childhood asthma may be associated with subsequent development of ADHD in early adolescence http://bit.ly/jWqO1k