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 significant public health concern. However, few investigations have distinguished 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 problematic 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 consider powder and crack cocaine as diagnostically and clinically equivalent. As such, researchers may wish to distinguish explicitly between powder and crack cocaine when assessing the characteristics and patterns 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;8: 264–270)
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 Humanities Research Council (MJS). The authors declare no conflicts of interest. Send correspondence and reprint requests to Sean P. Barrett, PhD, Department of Psychology & Neuroscience, Dalhousie University, Life Sciences Centre, 1355 Oxford St, Halifax, NS B3H 4R2, Canada. E-mail: [email protected]. C 2014 American Society of Addiction Medicine Copyright ISSN: 1932-0620/14/0804-0264 DOI: 10.1097/ADM.0000000000000047
264
P
roblematic cocaine use is a significant public health concern (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 example, 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 revealed distinct patterns of cocaine use, particularly in relation to polysubstance use and routes of administration. For example, 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 J Addict Med r Volume 8, Number 4, July/August 2014
Copyright © 2014 American Society of Addiction Medicine. Unauthorized reproduction of this article is prohibited.
J Addict Med r Volume 8, Number 4, July/August 2014
associated with cocaine use (Guindalini et al., 2006), research has yet to assess the patterns of use of these 2 forms of cocaine among opioid users, a clinical population in which problematic cocaine use is increasingly prevalent (Leri et al., 2003; Maremmani et al., 2007). Indeed, cocaine use has been reported as the most frequently abused substance among clients in methadone maintenance treatment (MMT) programs (eg, Peles et al., 2006), with treatment onset prevalence rates ranging between 40% and 80% and in-treatment rates ranging between 20% and 65% (Kosten et al., 1987, 1988; Hartel et al., 1995; Levin et al., 1996; Grella et al., 1997; Magura et al., 1998). Moreover, cocaine use has been found to complicate MMT program outcomes by increasing the incidence of treatment discontinuation and relapse (Stark and Campbell, 1991; Kreek, 1997). Despite the high incidence of cocaine use among opioid users and its adverse impact on MMT program outcomes, little is known about how powder and crack cocaine are used by opioid users and whether differences exist in the patterns of use of these 2 forms of cocaine. In this study, individuals enrolled in a low-threshold MMT program who reported the use of both powder and crack cocaine provided details about their lifetime use of these 2 forms of cocaine during confidential, face-toface interviews to address this gap in the literature. Using a within-subjects design, the goal of this study was to examine whether opioids users enrolled in a low-threshold MMT program reported distinct patterns and features of powder and crack cocaine use, including differences in age of initial and peak age, recent and lifetime use, routes of administration, and coadministration of other substances. In addition, this study aimed to assess whether the use of powder and crack cocaine was associated with distinct consequences of use, particularly in relation to criminal activity associated with cocaine use.
Powder and Crack Cocaine Use Among Opioid Users
TABLE 1. Demographic Information Reported by Sample Participants (N = 73) Characteristic Age, yrs Sex Male Female Ethnicity White Nonwhite/multiple ethnicities Marital status Single Married Separated/divorced Widowed Education Less than high school/equivalent Completed high school/equivalent Income $10,000 or less per year More than $10,000 per year Living status Renting Community shelter Other Current MMT program use Years enrolled before study interview Daily methadone dose (mg) Days/past 30 methadone used % enrolled in previous MMT programs Psychiatric medication Prescribed antidepressant (eg, citalopram) Prescribed antipsychotic (eg, quetiapine) Prescribed any psychiatric medication
% (n) of Sample or [M (SD)] [39.7 (8.9)] 61.6 (45) 38.4 (28) 82.2 (60) 17.8 (13) 53.4 (39) 23.3 (17) 17.8 (13) 5.5 (4) 52.1 (38) 47.9 (35) 69.5 (50) 31.5 (23) 82.2 (60) 15.1 (11) 1.4 (1) [3.0]* [109.1 (42.3)] [28.6 (3.8)] 45.2 (33) 34.3 (25) 24.7 (18) 64.4 (47)
*Median is reported because of the large standard deviation for this variable: M (SD) = 3.6 (3.1). MMT, methadone maintenance treatment.
Measures METHODS Participants Participants consisted of 73 clients enrolled in a lowthreshold MMT program in Halifax, Nova Scotia, Canada, who reported lifetime use of powder and crack cocaine and participated in a larger research project that examined various substance use behaviors and psychosocial variables. Compared with more traditional or “high-threshold” MMT programs, “low-threshold” programs do not require abstinence from all other substances in order for clients to remain in treatment (Royal College of Psychiatrists, 2000). The majority of clients enrolled in this MMT program (approximately 85%) are self-referred. No clients are mandated to treatment, and participation in the program is voluntary. All clients enrolled in the MMT program were eligible to participate in the larger research project; there were no exclusion criteria. However, given that this study focused on assessing powder and crack cocaine use among opioid users, only those participants in the larger research project who reported the use of both forms of cocaine were included in the analyses. This resulted in the exclusion of 2 participants who did not report lifetime use of powder cocaine. Demographic information on participants is displayed in Table 1. C
As the current data were part of a larger research project, only measures relevant to the present analyses are described herein. All measures were administered verbally so that no participant was excluded because of low literacy levels. Using a semistructured interview, participants were interviewed regarding demographics, methadone treatment (Table 1), and current and lifetime use of powder and crack cocaine, along with features and patterns of lifetime use. Specifically, a measure adapted from the Addiction Severity Index (McLellan et al., 1985) was used to assess lifetime use of powder and crack cocaine. On this measure, participants were asked to report if they ever used powder and crack cocaine, and, if relevant, their age of first and peak use for both forms of cocaine, and whether they had used either form of cocaine in the past 30 days, along with how many days in their life they have used powder and crack cocaine. Features and patterns of lifetime powder and crack cocaine use were assessed by asking participants how they have used the 2 forms of cocaine (ie, routes of administration), and whether they have ever deliberately used any other drugs or alcohol together with powder and crack cocaine and, if relevant, the substances coadministered. Furthermore, participants’ engagement in criminal activity to obtain powder and crack cocaine was assessed by asking participants whether
2014 American Society of Addiction Medicine
Copyright © 2014 American Society of Addiction Medicine. Unauthorized reproduction of this article is prohibited.
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Stewart et al.
they have ever obtained these forms of cocaine through illegal methods.
Procedure All clients enrolled in the MMT program were informed of their eligibility to participate in this study during client group meetings and through conversations with study personnel. Face-to-face, semistructured interviews were conducted by bachelor- and PhD-level psychology students who were trained and supervised by a registered PhD-level clinical psychologist. Potential participants were informed by study personnel that they were conducting a research study on substance abuse. They were informed that participation was voluntary and their decision to participate would not impact their treatment, and that all information gained from the study would be kept confidential. Clients who indicated their willingness to participate gave written informed consent and were compensated $20 at completion of the interview. All sampling, procedures, and materials were reviewed and approved by the Dalhousie University and Capital Health Research Ethics Boards.
RESULTS Statistical Analyses In a small percentage of cases, data were missing for some variables (eg, participant responded, “I don’t know”). Given that data were not missing for more than 10% of the sample, statistical analyses were not considered biased (Bennet, 2001), and no imputation was computed. McNemar tests were used to evaluate within-participant categorical variables, and paired-samples Student t tests were used to compare withinparticipant continuous variables.
Powder and Crack Cocaine Use Lifetime History The vast majority of participants reported using powder (83.6%; n = 61/73) and crack (86.3%; n = 63/73) cocaine more than 20 times over the course of their life. Results revealed that participants initiated powder cocaine use at a significantly younger age (M = 19.24 [SD = 6.13] years) than crack cocaine
use (M = 25.10 [SD = 9.19] years; t [72] = 6.53; P < 0.001). Similarly, participants’ peak use of powder cocaine occurred at a significantly younger age (M = 26.01 [SD = 7.67] years) than their peak use of crack cocaine (M = 33.68 [SD = 9.15] years; t [72] = 8.55; P < 0.001). In terms of recent cocaine use, participants were significantly more likely to report using crack cocaine (53.4%; n = 39/73) than powder cocaine (11%; n = 8/73) in the 30 days before taking part in the study (χ 2 [72] = 29.12; P < 0.001).
Patterns and Features of Lifetime Powder and Crack Cocaine Use On the basis of examination of Table 2, differences in routes of administration can be observed between participants’ lifetime use of powder and crack cocaine. Although almost all participants reported using powder cocaine via intranasal administration, a significantly smaller proportion of participants reported using crack cocaine in this manner (P < 0.001). Injecting cocaine was found to be a common route of administration for both forms of cocaine, although significantly more prevalent when using powder cocaine (P = 0.005). Furthermore, whereas a small majority of participants reported smoking powder cocaine (eg, mixing powder cocaine with tobacco or marijuana and smoking it), a significantly higher proportion of participants administered crack cocaine in this manner (eg, smoking crack cocaine through a pipe; P < 0.001). Finally, oral administration of powder and crack cocaine was not common among participants, and no significant differences were observed between participants’ use of the 2 forms of cocaine via oral administration (P = 1.00). Polysubstance use was prevalent for both forms of lifetime cocaine use, with 86.6% (n = 58/67) of powder cocaine and 87% (n = 60/69) of crack cocaine users reporting coadministration of other substances. As displayed in Table 2, a large proportion of participants coadministered alcohol, cannabis, prescription opioids (excluding methadone), and sedatives/tranquilizers with powder and crack cocaine. Although participants did not significantly differ in their use of alcohol (P = 0.439) or cannabis (P = 0.109) with powder
TABLE 2. Within-Participant Comparisons Between Patterns of Lifetime Use of Powder and Crack Cocaine Use Characteristic Method of cocaine administration* Intranasal Injection Smoking Oral Polysubstance use† Alcohol Cannabis Heroin Prescription opioids‡ Sedatives/tranquilizers Cocaine obtained through criminal activity§
% of Sample (n) Using Powder Cocaine
% of Sample (n) Using Crack Cocaine
McNemar χ 2 (df = 1) Test (P) Between Powder and Crack Cocaine
95.6 (64) 80.6 (54) 58.2 (39) 10.5 (7)
4.4 (3) 62.3 (43) 100 (69) 10.1 (7)
61.00 (
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 significant public health concern. However, few investigations have distinguished 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 problematic 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 consider powder and crack cocaine as diagnostically and clinically equivalent. As such, researchers may wish to distinguish explicitly between powder and crack cocaine when assessing the characteristics and patterns 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;8: 264–270)
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 Humanities Research Council (MJS). The authors declare no conflicts of interest. Send correspondence and reprint requests to Sean P. Barrett, PhD, Department of Psychology & Neuroscience, Dalhousie University, Life Sciences Centre, 1355 Oxford St, Halifax, NS B3H 4R2, Canada. E-mail: [email protected]. C 2014 American Society of Addiction Medicine Copyright ISSN: 1932-0620/14/0804-0264 DOI: 10.1097/ADM.0000000000000047
264
P
roblematic cocaine use is a significant public health concern (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 example, 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 revealed distinct patterns of cocaine use, particularly in relation to polysubstance use and routes of administration. For example, 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 J Addict Med r Volume 8, Number 4, July/August 2014
Copyright © 2014 American Society of Addiction Medicine. Unauthorized reproduction of this article is prohibited.
J Addict Med r Volume 8, Number 4, July/August 2014
associated with cocaine use (Guindalini et al., 2006), research has yet to assess the patterns of use of these 2 forms of cocaine among opioid users, a clinical population in which problematic cocaine use is increasingly prevalent (Leri et al., 2003; Maremmani et al., 2007). Indeed, cocaine use has been reported as the most frequently abused substance among clients in methadone maintenance treatment (MMT) programs (eg, Peles et al., 2006), with treatment onset prevalence rates ranging between 40% and 80% and in-treatment rates ranging between 20% and 65% (Kosten et al., 1987, 1988; Hartel et al., 1995; Levin et al., 1996; Grella et al., 1997; Magura et al., 1998). Moreover, cocaine use has been found to complicate MMT program outcomes by increasing the incidence of treatment discontinuation and relapse (Stark and Campbell, 1991; Kreek, 1997). Despite the high incidence of cocaine use among opioid users and its adverse impact on MMT program outcomes, little is known about how powder and crack cocaine are used by opioid users and whether differences exist in the patterns of use of these 2 forms of cocaine. In this study, individuals enrolled in a low-threshold MMT program who reported the use of both powder and crack cocaine provided details about their lifetime use of these 2 forms of cocaine during confidential, face-toface interviews to address this gap in the literature. Using a within-subjects design, the goal of this study was to examine whether opioids users enrolled in a low-threshold MMT program reported distinct patterns and features of powder and crack cocaine use, including differences in age of initial and peak age, recent and lifetime use, routes of administration, and coadministration of other substances. In addition, this study aimed to assess whether the use of powder and crack cocaine was associated with distinct consequences of use, particularly in relation to criminal activity associated with cocaine use.
Powder and Crack Cocaine Use Among Opioid Users
TABLE 1. Demographic Information Reported by Sample Participants (N = 73) Characteristic Age, yrs Sex Male Female Ethnicity White Nonwhite/multiple ethnicities Marital status Single Married Separated/divorced Widowed Education Less than high school/equivalent Completed high school/equivalent Income $10,000 or less per year More than $10,000 per year Living status Renting Community shelter Other Current MMT program use Years enrolled before study interview Daily methadone dose (mg) Days/past 30 methadone used % enrolled in previous MMT programs Psychiatric medication Prescribed antidepressant (eg, citalopram) Prescribed antipsychotic (eg, quetiapine) Prescribed any psychiatric medication
% (n) of Sample or [M (SD)] [39.7 (8.9)] 61.6 (45) 38.4 (28) 82.2 (60) 17.8 (13) 53.4 (39) 23.3 (17) 17.8 (13) 5.5 (4) 52.1 (38) 47.9 (35) 69.5 (50) 31.5 (23) 82.2 (60) 15.1 (11) 1.4 (1) [3.0]* [109.1 (42.3)] [28.6 (3.8)] 45.2 (33) 34.3 (25) 24.7 (18) 64.4 (47)
*Median is reported because of the large standard deviation for this variable: M (SD) = 3.6 (3.1). MMT, methadone maintenance treatment.
Measures METHODS Participants Participants consisted of 73 clients enrolled in a lowthreshold MMT program in Halifax, Nova Scotia, Canada, who reported lifetime use of powder and crack cocaine and participated in a larger research project that examined various substance use behaviors and psychosocial variables. Compared with more traditional or “high-threshold” MMT programs, “low-threshold” programs do not require abstinence from all other substances in order for clients to remain in treatment (Royal College of Psychiatrists, 2000). The majority of clients enrolled in this MMT program (approximately 85%) are self-referred. No clients are mandated to treatment, and participation in the program is voluntary. All clients enrolled in the MMT program were eligible to participate in the larger research project; there were no exclusion criteria. However, given that this study focused on assessing powder and crack cocaine use among opioid users, only those participants in the larger research project who reported the use of both forms of cocaine were included in the analyses. This resulted in the exclusion of 2 participants who did not report lifetime use of powder cocaine. Demographic information on participants is displayed in Table 1. C
As the current data were part of a larger research project, only measures relevant to the present analyses are described herein. All measures were administered verbally so that no participant was excluded because of low literacy levels. Using a semistructured interview, participants were interviewed regarding demographics, methadone treatment (Table 1), and current and lifetime use of powder and crack cocaine, along with features and patterns of lifetime use. Specifically, a measure adapted from the Addiction Severity Index (McLellan et al., 1985) was used to assess lifetime use of powder and crack cocaine. On this measure, participants were asked to report if they ever used powder and crack cocaine, and, if relevant, their age of first and peak use for both forms of cocaine, and whether they had used either form of cocaine in the past 30 days, along with how many days in their life they have used powder and crack cocaine. Features and patterns of lifetime powder and crack cocaine use were assessed by asking participants how they have used the 2 forms of cocaine (ie, routes of administration), and whether they have ever deliberately used any other drugs or alcohol together with powder and crack cocaine and, if relevant, the substances coadministered. Furthermore, participants’ engagement in criminal activity to obtain powder and crack cocaine was assessed by asking participants whether
2014 American Society of Addiction Medicine
Copyright © 2014 American Society of Addiction Medicine. Unauthorized reproduction of this article is prohibited.
265
J Addict Med r Volume 8, Number 4, July/August 2014
Stewart et al.
they have ever obtained these forms of cocaine through illegal methods.
Procedure All clients enrolled in the MMT program were informed of their eligibility to participate in this study during client group meetings and through conversations with study personnel. Face-to-face, semistructured interviews were conducted by bachelor- and PhD-level psychology students who were trained and supervised by a registered PhD-level clinical psychologist. Potential participants were informed by study personnel that they were conducting a research study on substance abuse. They were informed that participation was voluntary and their decision to participate would not impact their treatment, and that all information gained from the study would be kept confidential. Clients who indicated their willingness to participate gave written informed consent and were compensated $20 at completion of the interview. All sampling, procedures, and materials were reviewed and approved by the Dalhousie University and Capital Health Research Ethics Boards.
RESULTS Statistical Analyses In a small percentage of cases, data were missing for some variables (eg, participant responded, “I don’t know”). Given that data were not missing for more than 10% of the sample, statistical analyses were not considered biased (Bennet, 2001), and no imputation was computed. McNemar tests were used to evaluate within-participant categorical variables, and paired-samples Student t tests were used to compare withinparticipant continuous variables.
Powder and Crack Cocaine Use Lifetime History The vast majority of participants reported using powder (83.6%; n = 61/73) and crack (86.3%; n = 63/73) cocaine more than 20 times over the course of their life. Results revealed that participants initiated powder cocaine use at a significantly younger age (M = 19.24 [SD = 6.13] years) than crack cocaine
use (M = 25.10 [SD = 9.19] years; t [72] = 6.53; P < 0.001). Similarly, participants’ peak use of powder cocaine occurred at a significantly younger age (M = 26.01 [SD = 7.67] years) than their peak use of crack cocaine (M = 33.68 [SD = 9.15] years; t [72] = 8.55; P < 0.001). In terms of recent cocaine use, participants were significantly more likely to report using crack cocaine (53.4%; n = 39/73) than powder cocaine (11%; n = 8/73) in the 30 days before taking part in the study (χ 2 [72] = 29.12; P < 0.001).
Patterns and Features of Lifetime Powder and Crack Cocaine Use On the basis of examination of Table 2, differences in routes of administration can be observed between participants’ lifetime use of powder and crack cocaine. Although almost all participants reported using powder cocaine via intranasal administration, a significantly smaller proportion of participants reported using crack cocaine in this manner (P < 0.001). Injecting cocaine was found to be a common route of administration for both forms of cocaine, although significantly more prevalent when using powder cocaine (P = 0.005). Furthermore, whereas a small majority of participants reported smoking powder cocaine (eg, mixing powder cocaine with tobacco or marijuana and smoking it), a significantly higher proportion of participants administered crack cocaine in this manner (eg, smoking crack cocaine through a pipe; P < 0.001). Finally, oral administration of powder and crack cocaine was not common among participants, and no significant differences were observed between participants’ use of the 2 forms of cocaine via oral administration (P = 1.00). Polysubstance use was prevalent for both forms of lifetime cocaine use, with 86.6% (n = 58/67) of powder cocaine and 87% (n = 60/69) of crack cocaine users reporting coadministration of other substances. As displayed in Table 2, a large proportion of participants coadministered alcohol, cannabis, prescription opioids (excluding methadone), and sedatives/tranquilizers with powder and crack cocaine. Although participants did not significantly differ in their use of alcohol (P = 0.439) or cannabis (P = 0.109) with powder
TABLE 2. Within-Participant Comparisons Between Patterns of Lifetime Use of Powder and Crack Cocaine Use Characteristic Method of cocaine administration* Intranasal Injection Smoking Oral Polysubstance use† Alcohol Cannabis Heroin Prescription opioids‡ Sedatives/tranquilizers Cocaine obtained through criminal activity§
% of Sample (n) Using Powder Cocaine
% of Sample (n) Using Crack Cocaine
McNemar χ 2 (df = 1) Test (P) Between Powder and Crack Cocaine
95.6 (64) 80.6 (54) 58.2 (39) 10.5 (7)
4.4 (3) 62.3 (43) 100 (69) 10.1 (7)
61.00 (
