"Although no stereotypical withdrawal syndrome occurs when amphetamines are stopped, EEG changes occur, considered by some experts to fulfill the physical criteria for dependence. Abruptly stopping use may uncover or exacerbate underlying depression or precipitate a serious depressive reaction. Withdrawal is often followed by 2 or 3 days of intense fatigue or sleepiness and depression."

Source

"Amphetamine," The Merck Manual for Health Care Professionals, Special Subjects: Drug Use and Dependence: Amphetamines, Merck & Co. Inc., Revised: July 2008.
http://www.merckmanuals.com/p…