Clinical Textbook of Addictive Disorders 3rd ed - R. Frances, S. Miller, A. Mack (Guilford, 2005) WW

11. Polysubstance Use, Abuse, and Dependence 247denotes that the identified subject or sample has two or more formal SUD diagnoses,at least meeting criteria for substance abuse, or meets it by reasonableproxy, such as seeking treatment. “Multiple substance dependence” means thatthe identified subject or sample meets formal or reasonable proxy criteria fortwo or more substance dependence disorders.“Polysubstance Abuse”Although there was a diagnostic category of “mixed substance abuse” in DSM-III (American Psychiatric Association, 1980, p. 179), there is no diagnosisof polysubstance abuse in DSM-IV-TR (American Psychiatric Association,2000). There may not be many people who abuse multiple substances over timewith clinically significant impact, for whom no one substance is sufficient tomake formal abuse criteria. This is because one needs only to satisfy one of thefour DSM-IV criteria to pass the threshold for a substance abuse diagnosisrelated to that particular substance. However, it is conceivable that one couldmeet a criterion for substance abuse based on use of multiple substances, but noton one in particular. For example, a person could have two arrests for drivingunder the influence, one for alcohol and the other for cannabis, in the sameyear.Descriptive ApproachesPolydrug Use or Polysubstance UseMost broadly, the literature frequently describes “polydrug use” or “polysubstanceuse.” This nondiagnostic designation generally describes the use ofmultiple substances rather than framing the use and its effects in clinical terms,which is the intent of diagnosis. As such, polydrug use describes, at minimum,the use of multiple substances, whether licit or illicit. In the treatment researchliterature, “polydrug use” is often used to describe the lifetime number of drugsregularly used to a threshold SUD, in addition to the index substance (Ball,Carroll, Babor, & Rounsaville, 1995; Feingold, Ball, Kranzler, & Rounsaville,1996). However, in other than addiction or mental health treatment settings,the expressions “polysubstance use” or “polysubstance abuse” are frequentlymeant to describe the use by subjects of as few as two substances, such ascocaine and alcohol, alcohol and cannabis, or opiates and cocaine (Ross,Kohler, Grimley, & Bellis, 2003). In a more differentiated conceptualization,the use of multiple substances that cause impairment is frequently described as“polydrug abuse.”In an effort to further distinguish patterns of use, Grant and Hartford(1990) framed “polydrug use” either as simultaneous, which is the use of multipledrugs at the same occasion, or concurrent, which is the use of differentsubstances on different occasions. Use of different substances is common