Thirty-nine subjects, including 20 controls (14 women/ 6men, 33 SD 11 yrs old) and 19 substance-dependent individuals (SDI) (9 women/10 men, 35 SD 7 yrs old) participated in this study. SDI were recruited from the University of Colorado School of Medicine Addiction Research and Treatment Service (ARTS), a long-term residential treatment service. Inclusion criteria included dependence on one or more illicit substances, using DSM-IV criteria. Inclusion criteria for the controls were no diagnosis of substance abuse or dependence. Exclusion criteria for all participants included neurological illness, schizophrenia or bipolar disorder, prior significant head trauma, positive HIV status, diabetes, Hepatitis C, or other major medical illness, and IQ less than 80. All participants provided written informed consent approved by the Colorado Multiple Institutional Review Board.
