ORIGINAL RESEARCH Powder and Crack Cocaine Use Among Opioid Users: Is All Cocaine the Same? Melissa J. Stewart, MA, Heather G. Fulton, PhD, and Sean P. Barrett, PhD Objectives: Problematic cocaine use is highly prevalent and is a sig- nificant public health concern. However, few investigations have dis- tinguished between the 2 formulations of cocaine (ie, powder and crack cocaine) when examining the characteristics of cocaine use. Moreover, research has yet to assess the patterns of powder and crack cocaine use among opioid users, a clinical population in which prob- lematic cocaine use is increasingly common. Using a within-subjects design, this study examined whether opioid users reported different patterns and features of powder and crack cocaine use, along with distinct trajectories and consequences of use. Methods: Seventy-three clients enrolled in a low-threshold methadone maintenance treatment were interviewed regarding their lifetime use of powder and crack cocaine. Results: Compared with crack cocaine, initiation and peak use of powder cocaine occurred at a significantly younger age. In relation to recent cocaine use, participants were significantly more likely to report using crack cocaine than using powder cocaine. Differences in routes of administration, polysubstance use, and criminal activity associated with cocaine use were also found between the 2 forms of cocaine. Conclusions: Results suggest that it may not be appropriate to con- sider powder and crack cocaine as diagnostically and clinically equiv- alent. As such, researchers may wish to distinguish explicitly between powder and crack cocaine when assessing the characteristics and pat- terns of cocaine use among substance users and treat these 2 forms of cocaine separately in analyses. Key Words: abuse, crack cocaine, opioid users, powder cocaine (J Addict Med 2014;00: 1–7) From the Department of Psychology & Neuroscience (MJS, SPB), Dalhousie University, Halifax, Nova Scotia, Canada; and Burnaby Centre for Mental Health and Addiction (HGF), Burnaby, British Columbia, Canada. Received for publication September 23, 2013; accepted April 14, 2014. Supported by the Canadian Institutes of Health Research (SPB, HGF), Killam Doctoral Research Award (MJS, HGF), and Social Sciences and Human- ities Research Council (MJS). The authors declare no conflicts of interest. Send correspondence and reprint requests to Sean P. Barrett, PhD, Depart- ment of Psychology & Neuroscience, Dalhousie University, Life Sci- ences Centre, 1355 Oxford St, Halifax, NS B3H 4R2, Canada. E-mail: sean.barrett@dal.ca. Copyright C  2014 American Society of Addiction Medicine ISSN: 1932-0620/14/000000-0001 DOI: 10.1097/ADM.0000000000000047 P roblematic cocaine use is a significant public health con- cern (United Nations Office on Drugs and Crime, 2011). In the substance use literature, research has tended to treat cocaine as a single drug despite the fact that it is available in 2 distinct forms—cocaine hydrochloride (ie, powder cocaine) and crack cocaine. Whereas cocaine hydrochloride is typically purchased in powdered form, crack cocaine is prepared from cocaine hydrochloride and is purchased as “rocks.” There is evidence suggesting that these different forms of cocaine have distinct subjective effects and may be used in a polysubstance context in different ways (Gossop et al., 2006a, 2006b). For ex- ample, different patterns of combined cocaine and alcohol use have been reported by powder and crack cocaine users such that powder cocaine users report more frequent and heavy drinking than crack cocaine users. Moreover, whereas powder cocaine users tend to use cocaine and alcohol concurrently, crack cocaine users tend to use alcohol at the end of their session of drug use (Gossop et al., 2006a, 2006b). There is also preliminary evidence suggesting that powder and crack cocaine users, and dual users of these 2 forms of cocaine, report unique characteristics of cocaine use (Guindalini et al., 2006). An examination of these subgroups of cocaine users in treatment for cocaine-related problems re- vealed distinct patterns of cocaine use, particularly in relation to polysubstance use and routes of administration. For exam- ple, whereas intranasal administration was the most common route of administration among powder and dual cocaine users, smoking was the most common route among crack cocaine users. Furthermore, dual use of powder and crack cocaine was found to be associated with more problematic behaviors, such as increased polysubstance use and involvement in criminal behavior (Guindalini et al., 2006). Although such findings, along with those reported by Gossop and colleagues (2006a, 2006b), have increased our understanding of the distinct patterns of powder and crack cocaine use, it remains unclear as to whether such results relate to different formulations of cocaine or to individual difference effects because of the between-subjects designs used in these studies. To provide insight into these questions, it is essential that research allow for within-subject comparisons of individuals who report concurrent use of powder and crack cocaine. However, to date, no investigations have used within-subject designs when examining the patterns of powder and crack cocaine use. Moreover, although previous research has shed light on the different patterns of powder and crack cocaine use among individuals who concurrently consume alcohol (eg, Gossop et al., 2006a, 2006b), and individuals in treatment for problems Copyright © 2014 American Society of Addiction Medicine. Unauthorized reproduction of this article is prohibited. J Addict Med  Volume 00, Number 00, 00 2014 1