The purpose of the study is to determine if citicoline (a nutritional supplement) is effective in helping people reduce their dependence on methamphetamine. The investigators will use neuroimaging to look at the structure and chemical make up of the brain at the start of the study and after 8-9 weeks of treatment of citicoline or placebo.

This is a prospective, randomized, double-blind, placebo-controlled study, in which we will systematically evaluate the therapeutic effects of citicoline, which may both increase dopamine and normalize cognitive and structural deficits in the brains of methamphetamine dependent subjects. Methamphetamine dependent subjects will undergo baseline and repeat cognitive assessments after 8-9 weeks of placebo or oral citicoline as a nutritional supplement. We will also evaluate the chemical and structural changes in brain regions identified by magnetic resonance spectroscopy (MRS), diffusion tension imaging (DTI) and cortical thickness, which in turn are expected to recover after 8-9 weeks of citicoline treatment. Specific brain regions of interest include the prefrontal cortices, temporal cortex, and the caudate/putamen all of which are known to be involved in the pathophysiology of methamphetamine dependence.

Methamphetamine Dependent Subject Eligibility:

Inclusion Criteria:

• Subjects who use methamphetamine as their preferred drug of abuse.
• Subjects must be between the ages of 18 and 45 years.
• Subjects must have recent methamphetamine use (within 6 months of screening).
• Subjects must have an established residence and phone.
• Subjects must be able to give informed consent.

Exclusion Criteria:

• Significant current or past medical, neurological, or psychiatric co-morbidity including cardiovascular, renal, and endocrine disorder, as identified by medical history.
• Pregnant subjects - due to the unknown effects of MRI on a fetus. In addition, women of childbearing potential who will not practice a medically accepted method of contraception will be excluded. Female subjects who are of child-bearing potential will have to pass a urine pregnancy test before each visit.
• Subjects who, in the investigator's judgment, pose a current serious homicidal or suicidal risk.
• Subjects who will not likely be able to comply with the study protocol.
• Subjects who have any contraindication to an MR scan.
• Hypersensitivity to any of the study drugs or excipients
• Subjects with current DSM-IV diagnosis of a major mental illness. Major illness will be defined as Major Depression, Manic Depression, Schizophrenia, Dissociative Disorder, other psychotic illnesses, Attention-Deficit Hyperactivity Disorder, Post Traumatic Stress Disorder, Borderline Personality Disorder, Reactive Attachment Disorder, and Panic Disorder.
• Predominant alcohol or other substance dependence as preferred drug of abuse.
• Positive HIV test result.
• An individual having any pending legal or criminal charge or action, or who has pending or a reasonable potential for court involvement, or a person who is incarcerated or is in detention, or who is pending or having completed a competency evaluation or commitment procedure.

Healthy Control Subject Eligibility:

Inclusion Criteria:

• Subjects must be between the ages of 18 and 45 years.
• Subjects must be able to give informed consent.
• To have an established residence and phone.

Exclusion Criteria:

• Significant medical, neurological, or psychiatric disorders
• Pregnant subjects - due to the unknown effects of MRI on a fetus. In addition, women of childbearing potential who will not practice a medically accepted method of contraception will be excluded. Female subjects who are of child-bearing potential will have to pass a urine pregnancy test before each visit.
• Subjects who have any contraindication to an MR scan.
• Subjects unable to comply with protocol.
• Positive HIV test result.
• Positive urine drug screen.