Methamphetamine-Quetiapine Interactions in Humans

Inclusion Criteria: 1. Must be between the ages of 18-50. 2. Must have experience with IV methamphetamine use, with self-reported recent history of weekly use being greater than the total administered in the study. Recent use will be confirmed by a urine toxicology screen positive for amphetamines. We will recruit moderate to frequent users of methamphetamine. Moderate use is defined as use from once or twice every six weeks to weekly. Frequent users are defined as individuals who use greater than weekly. 3. Must have recent use confirmed by a urine toxicology screen positive for amphetamines. 4. Must not be seeking treatment for methamphetamine abuse/dependence. Exclusion Criteria: 1. Ill health (major cardiovascular, renal, endocrine, hepatic disorder). 2. Current diagnosis of other drug or alcohol physical dependence (other than nicotine or caffeine). 3. History of major organic psychiatric disorder (psychosis, schizophrenia, bipolar, mania) or significant psychiatric symptoms at the time of evaluation for study participation, including suicidal ideation. 4. Pregnancy, plans to become pregnant or fertile women without adequate means of contraception. 5. Present or recent use of over-the-counter or prescription psychoactive drug or drugs that would have major interaction with drugs to be tested. 6. Medical contraindication to or prior serious adverse effects from methamphetamine or stimulants (i.e., seizures, cardiac arrest) or medical contraindication to test agents (see risks section). Significant physical or psychiatric illness which might impair the ability to safely complete the study or that might be complicated by the study drugs, including prior seizures (after age 8) or other active neurological disease or clinically significant abnormalities on physical examination or screening laboratory values. 7. Current enrollment in a methamphetamine, alcohol, or other drug treatment program or current legal problems relating to methamphetamine, alcohol, or other drug use, including awaiting trial or supervision by a parole or probation officer 8. Body Mass Index \>30 or \<18 9. Currently trying to quit methamphetamine use or seeking treatment for methamphetamine use 10. History of serious adverse event or hypersensitivity to methamphetamine or other study drugs 11. Currently taking any medication (including highly active antiretroviral therapy (HAART) for HIV) other than over-the-counter nonsteroidal anti-inflammatory medications, topical medications, inhaled asthma therapy, and over-the-counter nonsedating antihistamines 12. Use within the last month of the Vicks Nasal Inhaler or medications that are metabolized to methamphetamine (e.g. selegiline) \-