Developmental brain anomalies in children with attention-deficit hyperactivity disorder

The pathoetiology of attention-deficit hyperactivity disorder (ADHD) has be en considered to be neurodevelopmental, yet the timing and processes involv ed are not clearly identified. Neurodevelopmental brain anomalies have been associated with a variety of psychiatric conditions. However, they have ne ver been evaluated in a population of patients with ADHD. This study was de signed to determine the frequency of specific developmental brain anomalies in a group, of children with ADHD (n = 85; mean age, 10.9 years) and healt hy control children (n = 95; mean age, 11.7 years) by visually inspecting b rain magnetic resonance imaging scans. Compared to controls, the ADHD group showed an increase in frequency of two developmental anomalies: (1) gray-m atter heterotopia, a neuronal migration anomaly, in 2 of 85 patients versus 0 of 95 controls; and (2) posterior fossa abnormality (excess cerebrospina l fluid in the posterior fossa) in 8 of 85 patients versus 2 of 95 controls . There were no differences in frequency of enlarged cavum septi pellucidi between the two groups. These findings support and extend the idea that ADH D is of developmental origin, and further suggest that the timing of aberra nt brain development could be in early gestation.