Although there are limited reports directly investigating the effects of captopril on the function of these neurotransmitters, there is considerable indirect evidence to suggest that ACE inhibition would affect all three of these systems: neuropeptides that are metabolised by ACE affect the function of serotonin (Jenkins, 2008), dopamine (Prus et al., 2007) and noradrenaline (Sumners and Phillips, 1983) in neuronal networks implicated in ADHD. The gene discussed is ACE; the disease is attention deficit-hyperactivity disorder.