Attention deficit hyperactivity disorder (ADHD) may be well known, but there is still a great deal that scientists don't know about it.

One of the more difficult forms of drug abuse to control among teens is prescription drug abuse. Prescription drugs, like stimulants prescribed for attention deficit hyperactivity disorder, can be abused for recreational purposes. 

Though the past decade has seen increases in prescription drugs used among adults, the use of doctor-prescribed medications among children has actually declined - with some exceptions.