We aim to recruit 30 children with a combined type of attention deficit/hyperactivity-disorder (ADHD) and 30 controls aged 9-12 years. The children will go through a careful clinical characterization, neuropsychological testing, MR scanning and measuring of ERP's. The participants will receive treatment as usual and both groups will be rescanned and retested after 2 years in order to follow-up their development of ADHD and affective symptoms, their level of cognitive control and their ability to regulate emotions. Clinical and neuropsychological measures will allow to test whether a subgroup of children with ADHD and affective problems specifically displays problems in emotion regulation and abnormal patterns of neuronal activation during the fMRI image a cquisitions and in the ERP measures. Moreover, the study design allows for contrasting regional neuronal activations during a pure cognitive task (Flanker Task) with activations during a task that involves the evaluation of emotional arousing stimuli (neu tral faces and faces with emotional content). Children with ADHD and controls alike will activate different regions of the prefrontal cortex (PFC) when presented a task that elicits emotions (ventromedial PFC, orbitofrontal PFC) or a cognitive task (dorso lateral PFC). Both groups will increase their ability of prefrontally mediated emotional regulation during the 2 year period, although children with ADHD will show a delay of maturation of fronto-limbic connections during baseline and also after 2 years. The high level of parametric phenotypic characterization in both groups will allow to search for specific underlying genotypic constellations in the group of children with ADHD in relation to affective symptoms, probably involving alterations of the serot onergic metabolism. We will also explore whether a subgroup of children with ADHD and anxiety problems possibly displays a different pattern of development of their fronto-limbic interactions.