Attention-deficit/hyperactivity disorder (ADHD) in childhood: The Behaviour and the Neurobiology   Prof. Terje Sagvolden (University of Oslo, Norway.) Prof. Bob Oades (University Clinic of Child and Adolescent Psychiatry, Essen, Germany.)

Recently interdisciplinary investigations involving collaboration between clinical research and the basic neurosciences have thrown new light on the widespread developmental dysfunctions grouped together as childhood attention-deficit/hyperactivity disorder (ADHD). The high heritability of the disorder has been related to a number of features defining monoaminergic function. In turn the success of catecholaminergic medications and animal models of various symptoms (e.g. in the spontaneously hypertensive rat) point not only to the neurochemical bases underlying deficient attentional control and impulsivity in ‘hyperactive children’, but crucially to their altered responsiveness to reinforcement (e.g. delay aversion). In parallel, indices of monoaminergic function have been related in neuroimaging studies to the activation (or lack thereof) in patients’ brain regions (e.g. the frontal lobes) involved in important executive and reward functions. The addition of neurophysiological measures to such investigations has helped illustrate the nature of the delayed developmental processes of potential etiological importance. Illustrating the interactions beween these levels of analysis, an explanation of the underachievement of children with ADHD in terms of their high intra-individual variability of response organization will be proposed: this is a theory based on neuron-glia interactions. But we emphasize that recent and ongoing studies of these inter-disciplinary interactions will be illustrated in each of the four presentations. Heidi Aase: From the model to practice – experimental studies of the characteristics of children with ADHD. Terje Sagvolden: Anomalous perception of reinforcement and a dynamic developmental theory of ADHD: implications of hypodopaminergic function. Katya Rubia: Neuroimaging studies of ADHD: regional function and relationships to transmitter function. Bob Oades: Energy supply: a neuro-physiological interpretation for intra-individual variability, poor attention control, and maturation delays in ADHD.