The Food and Drug Administration on Wednesday confirmed what many Americans had already discovered the hard way: The country is experiencing a nationwide shortage of Adderall, the drug used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy.  

The FDA said the shortage of "amphetamine mixed salts" -- the drug behind the brand name -- is driven in large part by manufacturing delays at the largest manufacturer: Israel-based Teva Pharmaceuticals. 

Teva said the problems arose out of labor shortages that have been resolved. However, the shortage persists, and the end isn't imminent: A Teva spokesperson told NBC News that patients should expect "inventory recovery in the coming months" and "intermittent delays through end of year."