Characterization of [11C]Flumazenil to Image GABA Transmission in Healthy Adult Subjects and Subjects With Alcohol Dependence

Inclusion Criteria: Healthy Control Subjects: 1. Males or Females 18-45 2. Absence of present or past psychiatric conditions (including alcohol or drug dependence) 3. A negative urine drug screen 4. Medically Healthy Subjects with alcohol dependence: 1. Males or Females 18-45 2. Fulfill DSM-IV Diagnosis for Alcohol Dependence 3. Negative Urine Drug Screen 4. Negative Urine ETG/ETS 5. Medically Healthy 6. Abstinent from alcohol for a minimum of 1 month prior to scanning procedures Exclusion Criteria: Healthy Control Subjects: 1. Pregnancy or lactation, lack of effective birth control during 15 days before the scans 2. Presence or positive history of serious medical or neurological illness, including low hemoglobin. 3. Any use (within recent past 6 weeks) of amphetamines, opiates, cocaine, ecstasy PCP. 4. Metal implants or paramagnetic objects contained within the body which may interfere with the MRI scan (but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant. Dental fillings do not present a risk for MRI), as determined in consultation with a neuroradiologist and according to the guidelines set forth in the following reference book commonly used by neuroradiologists. 5. Currently employed as radiation worker; or participation in radioactive drug research protocols within the previous year such that the total cumulative annual radiation dose (i.e., from participation in the previous research studies and this study) would exceed the radiation dose limits specified in the FDA regulations at 21 CFR 361.1, Radioactive Drugs Considered Generally Safe and Effective (i.e. annual cumulative radiation dose limit = 5 rems to gonads, blood-forming organs, lens of eye, whole body; 15 rems to other organs). 6. Subjects with known hypersensitivity to flumazenil or benzodiazepines; subjects who have been given a benzodiazepine for control of a potentially life-threatening condition (e.g., control of intracranial pressure or status epilepticus or in patient who are showing signs of serious cyclic antidepressant overdose) Subjects with alcohol dependence: 1. Pregnancy or lactation, lack of effective birth control during 15 days before the scans 2. Presence or positive history of serious medical or neurological illness or any cardiovascular disease, low hemoglobin 3. Any other current major axis I psychiatric diagnosis except alcohol dependence (subjects with nicotine dependence will not be excluded) 4. Metal implants or paramagnetic objects contained within the body which may interfere with the MRI scan (but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant. Dental fillings do not present a risk for MRI), as determined in consultation with a neuroradiologist and according to the guidelines set forth in the following reference book commonly used by neuroradiologists. 5. Currently employed as radiation worker; or participation in radioactive drug research protocols within the previous year such that the total cumulative annual radiation dose (i.e., from participation in the previous research studies and this study) would exceed the radiation dose limits specified in the FDA regulations at 21 CFR 361.1, Radioactive Drugs Considered Generally Safe and Effective (i.e. annual cumulative radiation dose limit = 5 rems to gonads, blood-forming organs, lens of eye, whole body; 15 rems to other organs). 6. Subjects with known hypersensitivity to flumazenil or benzodiazepines; subjects who have been given a benzodiazepine for control of a potentially life-threatening condition (e.g., control of intracranial pressure or status epilepticus or in patient who are showing signs of serious cyclic antidepressant overdose)