Participant screening was initially conducted by a phone interview assessing alcohol use/dependence, use/dependence of other drugs, medical history, and mental health history. All participants were fully informed of the study’s procedures and aims and signed a consent form prior to their participation. Participation consisted of four sessions that lasted between 1.5 to 3 hours and included clinical, neuropsychological, electrophysiological, and neuroimaging assessments. All of the cognitive measures were administered during one session and were completed by all subjects in our sample. Over 95% of subjects completed all four sessions, most within two to three weeks. In rare cases, where scheduling was especially difficult, sessions were spread out up to six weeks. NAC subjects were asked to abstain from consuming alcohol for at least 24 hours prior to any lab visit. A Breathalyzer (Intoximeters, Inc., St. Louis, MO) test was administered to all subjects. A 0.000 alcohol concentration was required of all participants in all sessions. Subjects were compensated for time and travel expenses upon completion of each session. Subjects who completed the entire study were also given a completion bonus.
