Attention Deficit Hyperactivity Disorder,or ADHD, is the most common behavioraldisorder in children.
注意力不足多动症，或ADHD，是孩子中最常见的行为异常症。
It's usually first diagnosed in childhoodand often lasts into adulthood.
它通常是在孩童时期被发现，持续到成年期。
A child with ADHD might have troublepaying attention, daydream a lot, forgetor lose things often, talk too much, or actwithout thinking about the consequences.
患有ADHD的孩子可能很难集中注意力、经常做白日梦，经常丢三落四、说话太多或者做事不考虑后果。
Most children have trouble focusing orbehaving at some time or another, butkids with ADHD have these symptomsmuch longer than other kids, and thesymptoms cause serious problems athome, at school, and with friends.
There are many risk factors for ADHDand no single cause.
ADHD有很多风险因素，但没有直接原因。
Scientists believe that genetics play animportant role.
科学家认为基因在多动症中是一个很大的因素。
Researchers do not believe that ADHD iscaused by eating too much sugar orwatching too much TV.
研究人员不相信ADHD是因为吃了太多糖或看了太多电视导致的。
However, chaotic environments orinconsistent parenting can make ADHDsymptoms worse.
但是，混乱的环境或前后矛盾的养育会让ADHD恶化。
There is no single test to diagnose ADHD,and many other problems can havesimilar symptoms, including sleepdisorders, anxiety, depression, andcertain types of learning disabilities.