Some authors suggest that the number of symptoms necessary for the diagnosis in adolescents and adults might also need to be less than the number of symptoms required for the diagnosis in childhood. However, comorbidity is also a major problem. Differences in comorbidity with regard to type and prevalence probably vary across the age range and different samples such as a general population sample, a pediatric sample or a psychiatric sample. In younger children, language and learning disorders are also common comorbidities. Chronic tics and Tourette's disorder occur in a significant minority of children as do anxiety and mood disorder.
ADD is a clinical diagnosis.
The diagnosis is made on the basis of parent and child interviews and observations, behavior rating scales, physical and neurological examinations and cognitive testing. The core symptoms of ADD occur in other psychiatric disorders and in medical and neurological conditions. More specifically, it was stated that the symptoms disappeared with puberty. It is now clear that neither of these views is true. Over time, the inattention domain seems to be the most persistent and gross motor hyperactivity less so.