Finally, we established and characterized the zebrafish dbh mutant, a useful tool for studying other processes that are thought to involve NE, including the fight-or-flight response (Colwill and Creton, 2011), congestive heart failure (Thomas and Marks, 1978), cognitive disorders such as Alzheimer's (Chalermpalanupap et al., 2013) and Parkinson's diseases (Rommelfanger et al., 2007), and neuropsychiatric disorders including depression and ADHD (Chamberlain and Robbins, 2013). Here, DBH is linked to attention deficit-hyperactivity disorder.