The Efficacy and Neurobehavioural Mechanism of N-acetyl Cysteine (NAC) for Alcohol Dependence

Inclusion Criteria: * Male and female patients between the ages of 18 and 65 meeting DSM-IV criteria for current alcohol use disorder (this is an exclusion for the healthy control sample) * Able to understand and sign written informed consent * Must have a stable residence and be able to identify an individual who could locate subject if needed * Admitted for medical detoxification from alcohol (withdrawal study only) * Blood alcohol concentration of 0.00 (if completing brain imaging session) * Express a desire to achieve abstinence or to greatly reduce alcohol consumption (relapse prevention study only) Exclusion Criteria: * Clinically significant comorbidities or medical disease that might interfere with the evaluation of the study medication or present a safety concern. * Pregnant women and women of childbearing potential who do not practice a medically acceptable form of birth control * Women who are breastfeeding * Dependence on any substance other than nicotine * Court-mandated participation in alcohol treatment or pending incarceration (relapse prevention study only) * Treatment/ingestion during the previous week of benzodiazepines or other sedative-hypnotic medications or history of recent chronic treatment with sedative-hypnotic medications (withdrawal study only) * Dependence on any substance other than nicotine The following exclusion criteria are only applicable to participants undergoing the brain imaging session: * Extreme obesity * Pregnant or have any reason to believe they are pregnant; * Previous brain surgery; * Ever employed as a machinist, a welder or a metal worker; * Epilepsy * Metal items such as pacemakers; aneurysm clips in the brain; metal dental implants; metallic fragments in the eye or anywhere else; insulin pump; metal implants; hearing aid or a prosthetic device.