Phase 1: Patients with SUD who were either newly admitted (abstinent for <1 week) or in treatment in the RTF (abstinent <3 months) were administered the Adult ADHD Self-Report Scale Symptom Checklist (ASRS) v. 1.1 Screener. Patients who screened positive(>= 4 out 6 significant items) were then administered the Adult Clinician Diagnostic Scale (ACDS) v.1.2 to establish a diagnosis of ADHD and the Predictive Value Positive (PVP) in this population.