Comorbidity of dyslexia, dyspraxia, attention deficit disorder (ADD), attention deficit hyperactive disorder (ADHD), obsessive compulsive disorder (OCD) and Tourette's syndrome in children: A prospective epidemiological study

The patterns of comorbidity occurred with such frequency that it would suggest that there could be an argument for the downgrading of these conditions from disorders per se to symptoms and that further investigation might suggest that the patterns of comorbidity may fit the criteria for a developmental delay syndrome.