Based on findings of neurocognitive decrements in adolescent substance users (Tapert & Brown, 1999; Tapert et al., 2002), including users with primary marijuana and alcohol use (Brown et al., 2000; Medina et al., 2007; Tapert & Brown, 2000), we examined indices from measures that previously differentiated users from controls: Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) Digit Symbol total scaled score, Digit Span backward score and Digit Span total scaled score (Wechsler, 1997b); Paced Auditory Serial Addition Test (PASAT) 2-second and 3-second trial total scores (Gronwall, 1974); Delis-Kaplan Executive Function System (D-KEFS) TMT Number Sequencing, Letter Sequencing, and Switching scaled scores and TMT total errors (Delis, Kaplan, & Kramer, 2001); California Verbal Learning Test-II (CVLT-II) List A Trial 1 standard score (Delis, Kramer, Kaplan, & Ober, 2000); and Wechsler Memory Scale-Third Edition (WMS-III) Logical Memory first, immediate and delayed recall scaled scores and recognition total score (Wechsler, 1997a). Wechsler Abbreviated Scale of Intelligence (WASI) Vocabulary (Wechsler, 1999) and Wide Range Achievement Test – 3 (WRAT-3) Reading (Wilkinson, 1993) provided estimates of premorbid intellectual functioning.
