出典:Wiktionary
出典:『Wiktionary』 (2009/10/25 17:12 UTC 版)
attention-deficit hyperactivity disorder (uncountable)
出典:Wikipedia
出典:『Wikipedia』 (2011/08/10 15:32 UTC 版)
Attention deficit hyperactivity disorder (ADHD or AD/HD or ADD) is a developmental disorder. It is primarily characterized by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age.