Methamphetamine use is very common in the US and is associated with serious medical and psychiatric problems. There has also been a significant increase in the number of patients entering treatment for methamphetamine dependence, however, no pharmacologic treatment has been identified as effective in treating methamphetamine addiction. Given that withdrawal from methamphetamine is thought to contribute to relapse to methamphetamine use during early treatment, it is important to examine potential pharmacologic agents for alleviating withdrawal. Thus, this study is designed to study methamphetamine withdrawal in humans. To this end, 30 methamphetamine dependent participants (ages 18-65 years) will be entered into a 4-week residential study. Urine samples will be obtained at baseline to ensure recent methamphetamine use. Intake assessments will include cognitive testing, standardized assessment of depression and anxiety, profile of mood states, methamphetamine selective severity assessment, methamphetamine withdrawal assessment, sleep quality and quantity, a pre-attentional measure and attentional measure. Upon admission to the residential facility, all study participants will be started on (20-30mg) long acting amphetamine/d-amphetamine and stabilized over the first 5 days. After stabilization participants will be randomized based on sex, amphetamine withdrawal questionnaire score, and methamphetamine selective severity assessment score to either continued treatment with amphetamine/d-amphetamine or placebo for 2 weeks. All subjects will then be placed on placebo for the last 7 days. The investigators hypothesis is that stopping amphetamine administration in methamphetamine dependent individuals will negatively impact mood, sleep and cognitive function in a time-limited fashion that may differ depending upon the measure and that attentional, but not pre-attentional, measures will be adversely affected in those receiving placebo compared to those maintained on amphetamine.

Inclusion Criteria:

• 21-65 years old
• not currently enrolled in a treatment program
• history of methamphetamine use with recent use confirmed by a positive urine toxicology screen for amphetamines during the month prior to study entry
• self-reported Methamphetamine use on at least 15 of the past 30 days
• use of at least one half gram of methamphetamine per week during the month prior to study entry
• women of childbearing age must have a negative pregnancy test to enroll in this study

Exclusion Criteria:

• current diagnosis of alcohol, opiate, or sedative physical dependence
• ill health (e.g., major cardiovascular, renal, endocrine, hepatic disorder)
• history of schizophrenia, or bipolar type I disorder
• present or recent use of over-the-counter or prescription psychoactive drug or drug(s) that would be expected to have major interaction with d-amphetamine
• medical contraindication to receiving study medications (e.g., previous adverse reaction to d-amphetamine)
• chronic pain condition (due to impact on neurophysiological responses
• current suicidality or psychosis
• liver function tests (i.e., liver enzymes) greater than three times normal levels
• pregnancy or breastfeeding
• children 18-20 will be excluded because the P50 potential is not fully developed in children and adolescents