Effects of Amphetamine and Methamphetamine Use
"A paranoid psychosis may result from long-term use; rarely, the psychosis is precipitated by a single high dose or by repeated moderate doses. Typical features include delusions of persecution, ideas of reference (notions that everyday occurrences have special meaning or significance personally meant for or directed to the patient), and feelings of omnipotence. Some users experience a prolonged depression, during which suicide is possible. Recovery from even prolonged amphetamine psychosis is usual but is slow. The more florid symptoms fade within a few days or weeks, but some confusion, memory loss, and delusional ideas commonly persist for months."
"Amphetamines," The Merck Manual for Health Care Professionals, Special Subjects: Drug Use and Dependence: Amphetamines, Merck & Co. Inc. (July 2008).