The DUS is a single item screening tool to be used by clinicians rating the drug use of their own patients with severe mental illness.
Drake RE, Mueser KT, McHugo GJ. Clinician rating scales: Alcohol Use Scale (AUS), Drug Use Scale (DUS), and Substance Abuse Treatment Scale (SATS). IN: Outcomes Assessment in Clinical Practice. Edited by Sederer, L, and Dickey, B. Baltimore, MD: Williams & Wilkins, 1996.
Long CG; Hollin CR. Assessing comorbid substance use in detained psychiatric patients: issues and instruments for evaluating treatment outcome. Substance Use and Misuse 2009; 44(11):1602-1641.