Auswirkungen von Methylphenidat auf das präsynaptische dopaminerge System bei jungen, männlichen Erwachsenen mit Aufmerksamkeitsdefizit-Hyperaktivitätssyndrom: Eine 6-[18F]-Fluoro-L-Dihydroxyphenylalanin Positronen-Emissions-Tomography Studie

Abstract

Background: The dopaminergic system plays a key role in attention deficit hyperactivity disorder (ADHD). It was our aim to investigate the dopamine metabolism in young males with ADHD (medicated ones and ones who had never been treated) in comparison to healthy controls. Method: Dynamic [18F]L-DOPA PET scans were carried out on 8 ADHD patients who had never been treated with methylphenidate, on 17 treated ADHD patients and on 19 healthy controls. Results: Our results show a reduction of the dopamine turnover in ADHD patients who have been treated with methylphenidate. In comparison to untreated ADHD patients treated ADHD patients showed a decreased influx of Ki in bilateral putamen and bilateral amygdale. In comparison to healthy controls untreated patients showed a dysregulated dopaminergic system with increased and decreased uptake sites. Methylphenidate treatment was associated with a significantly lower Ki in the striatum and amygdale bilaterally in comparison to healthy controls. Conclusions: Untreated ADHD patients showed a dysregulation of presynaptic dopamine metabolism compared to controls. Methylphenidate treatment seems to downregulate dopamine turnover.