Journal of Substance Abuse, 5, 117-130 (1993)
Nicotine and Caffeine Use in Cocaine-Dependent Individuals Alan I. Budney, Stephen T. Higgins, John R. Hughes, Warren K. Bickel University of Vermont
Nicotine and caffeine use in 87 cocaine-dependent persons seeking treatment at an outpatient clinic were compared to use of those substances in a matched general population sample (n = 78). The prevalence of cigarette smoking was significantly greater in the cocaine-dependent sample (75% vs. 22%). Within the cocainedependent sample, smokers were younger, less educated, employed in lesser skilled jobs, and reported an earlier onset and more frequent use of cocaine. The prevalence of caffeine use was significantly less in the cocaine-dependent group (68% vs. 83%), although, among caffeine users, the cocaine group drank significantly more caffeinated beverages per day than matched controls (4.9 vs. 3.3). Interestingly, regular caffeine use was associated with less frequent cocaine use within the cocainedependent sample. To our knowledge, this study is the first to report on prevalence of smoking and caffeine use among cocaine-dependent individuals, and suggests that use of these other substances may influence the onset and pattern of cocaine use.
Cocaine-dependent individuals frequently abuse multiple substances (Higgins et al., 1991; Miller, G o o d , B e l k i n , & K l a h r , 1989; S c h n o l l , D a g h e s t a n i , K a r r i g a n , K i t c h e n , & H a n s e n , 1985; Weiss, M i r i n , G r i f f i n , & Michael, 1988). S u c h c o n c u r r e n t d r u g u s e m a y p r o d u c e a d v e r s e b e h a v i o r a l o r m e d i c a l e f f e c t s via d r u g i n t e r a c t i o n s ( K r e e k , 1987). M o r e o v e r , m u l t i p l e d r u g u s e m a y i n f l u e n c e c o c a i n e t r e a t m e n t o u t c o m e , a n d c o n s e q u e n t l y , r e q u i r e s c o n s i d e r a t i o n in t h e d e v e l o p m e n t of treatment interventions. The prevalence of marijuana and alcohol dependence a m o n g c o c a i n e - d e p e n d e n t i n d i v i d u a l s r a n g e s f r o m 2 5 - 8 9 % , a n d t h u s , it is n o t s u r p r i s i n g t h a t t h e l i t e r a t u r e a d d r e s s i n g o t h e r d r u g u s e in t h e c o c a i n e - d e p e n d e n t p o p u l a t i o n h a s f o c u s e d o n u s e o f t h e s e two s u b s t a n c e s ( B u d n e y , H i g g i n s , D e l a n e y , This article was presented, in part, at the annual conference of the American Psychological Association, August, 1991, San Francisco, CA. This work was conducted at the Human Behavioral Pharmacology Laboratory, Department of Psychiatry, University of Vermont. It was supported by the National Institute on Drug Abuse research grants R18DA06113 and R29DA04545, R01DA04843 and K02DA00109 (Dr. Hughes), T32DA07242 and R18DA06969, and National Institute of Mental Health grant MH-4720. Correspondence and requests for reprints should be sent to Stephen T. Higgins, University of Vermont, 38 Fletcher Place-lra Allen School, Burlington, VT 05401. 117
118
A.I. Budney, S.T. Higgins, I.R. Hughes, and W.K. Bickel
Kent, & Bickel, 1991 ; Higgins et al., 1991 ; Miller et al., 1989; Schnoll et al., 1985; Weiss et al., 1988). Yet, nicotine (tobacco) and caffeine use are also likely to be prevalent within the cocaine-dependent population, but to our knowledge, have not been systematically examined. Nicotine and Cocaine
High rates of cigarette smoking have been reported among drug abusers in general, but specific data for cocaine abusers has not been reported (Burling & Ziff, 1988). One might expect high rates of smoking among cocaine-dependent persons considering that the majority are also alcohol dependent or have other psychiatric disorders (Gawin & Kleber, 1990; Weiss et al., 1988). Each of those disorders is associated with a high prevalence of smoking (Bobo, 1991; Hughes, Hatsukami, Mitchell, & Dahlgren, 1986). The effects of nicotine-cocaine interactions have not been well studied. Both produce several similar adverse, behavioral, and stimulant-like mood effects (Cregler & Mark, 1986; Ettinger & Albin, 1989; Foltin & Fischman, 1991; Henningfield & Griffiths, 1981; Higgins, Bickel, Hughes, Lynn, & Capeless, 1990; USPHS, 1979; Wesnes & Warburton, 1983). Thus, concurrent use of the two may produce additive or synergistic effects. Whether these similar effects suggest that nicotine use would prompt, and thus increase, cocaine use, or would substitute for, and thus decrease, cocaine use is unclear. Although many believe nicotine effects are too subtle to influence cocaine use, nicotine use is strongly associated with illicit drug use (Henningfield, Clayton, & Pollin, 1990). Moreover, laboratory studies indicate that stimulants such as d-amphetamine and cocaine can increase smoking (Henningfield & Griffiths, 1981; Low, Jones, Carte, & Cadoret, 1984; Nemeth-Coslet, Henningfield, Katz, & Goldberg, 1986). Thus, prior reports document potentially important interactions among these substances. C a f f e i n e and C o c a i n e
Caffeine is used daily by approximately 85% of Americans and is receiving increased attention as a drug of abuse (Gilbert, 1976; Griffiths & Woodsen, 1989; Hughes et al., 1991; Hughes et al., 1993; Schreiber, Maffeo, Robins, Masters, & Bond, 1988). Caffeine use in cocaine-dependent persons has not been studied. However, a positive relationship between cigarette smoking and caffeine use has been documented (Istvan & Matarazzo, 1984), suggesting that if a high prevalence of smoking exists among cocaine-dependent individuals, high rates of caffeine use are likely as well. The prevalence of alcohol dependence is high among cocaine-dependent individuals (Higgins et al., 1991; Miller et al., 1989; Schnoll et al., 1985), but the relationship between caffeine and alcohol use is not clear (Ayers, Ruff, & Templer, 1976; Doucette & Willoughby, 1980; Istvan & Matarazzo, 1984; Klatsky, Friedman, Siegelaub, & Gerard, 1977; Verinis, 1986). Thus, it is difficult to predict how the prevalence of alcohol dependence might influence caffeine use in cocaine abusers. As with nicotine, caffeine and cocaine produce several similar behavioral and
Nicotine and Caffeine Use in Cocaine Dependence
119
stimulant-like cardiovascular effects (Foltin & Fischman, 1991; Gilbert, 1976; Higgins, Rush, Bickel, Hughes, & Capeless, 1992; James, 1991; Rush, Higgins, Bickel, & Hughes, 1992). Research with nonhumans indicates that combining caffeine and cocaine can offset behavioral effects observed with either drug alone, or can result in additive or supraadditive effects (Derlet, Tseng, & Albertson, 1992; Evans & Wenger, 1990; Logan, Carney, Holloway, & Seale, 1988; Misra, Vadlamani, & Pontani, 1986; Schenk, Horger, & Snow, 1990). Moreover, of potential importance to cocaine-dependence treatment is the research with nonhumans that suggests caffeine use may influence cocaine use. For example, caffeine partially substitutes for cocaine in drug-discrimination paradigms (Gauvin, Criado, Moore, & Holloway, 1990; Harland et al., 1989). As another example, caffeine pretreatment may enhance the acquisition of cocaine self-administration in rats (Horger, WeUman, Morien, Davies, & Schenk, 1991). Although it is difficult to predict how caffeine may influence cocaine use in humans, investigating possible interactions of these substances seems prudent. The purpose of this study was to estimate nicotine and caffeine use in cocainedependent persons, compare it to a general population sample, and determine if use of those substances was associated with different patterns of cocaine use. METHOD
Subjects Data were collected between January 1990 and July 1991 from 87 consecutive, cocaine-dependent individuals seeking treatment in a university-based outpatient clinic for treatment of cocaine dependence located in Burlington, Vermont. Only persons who completed an intake interview and who met DSMIII-R diagnostic criteria for current cocaine dependence were included in this study. Other comorbid substance-dependence disorders were diagnosed, but these were not classified as primary or secondary disorders. Subject characteristics are presented in Table 1 (p. 120). For use as a comparison group, data were collected from a general population sample in the same geographic area as the cocaine-dependent sample (Hale et al., 1993; Hughes et al., 1993). A random-digit-dial telephone survey of the greater Burlington, VT metropolitan area was conducted as part of the DSM-IV field trial. O f the 202 persons surveyed, 78 persons matched on sex and age with the cocaine sample were used as the comparison group. Slightly fewer subjects comprised the general population group used in this study because of difficulties matching men according to age. Only age and sex were employed as matching variables because use of other available variables such as education would have greatly reduced the size of the comparison group. Control subjects were queried about caffeine and nicotine, but not cocaine use, which was assumed to be rare. The majority of subjects in both groups were white men between the ages of 20 to 42 years. Approximately half were married, although a higher percentage of the cocaine-dependent sample were currently separated or divorced. The cocaine-dependent group averaged 10 to 14 years of education, whereas the general population group generally had at least some college education (Table 1).
120 T a b l e 1.
A.J. Budney, S.T. Higgins, J.R. Hughes, and W.K. Bickel Subject Characteristics Cocaine Dependent (n = 87)
Males (%) A g e (years) Race (% Caucasian) E d u c a t i o n (%) < 12 years 1 2 - 1 5 years -> 16 years Marital Status (%) married sep)div not m a r r i e d O c c u p a t i o n (Hollingshead Scale) Income (S/month)
General Population (n = 78)
76 (n = 66) 30.1 (5.4) • 100
73 (n = 57) 30.3 (6.7) a 95*
29 (n = 25) 59 (n = 51) 12 (n = 10)
04 (n = 3)* 45 (n = 35) 50 (n = 39)
24 (n = 21) 26 (n = 23) 49 (n = 43) 5.2 (2.6)a 935 (966) ~
45 (n = 35)*
9 (n = 7) 46 (n = 36)
Cocaine Years o f r e g u l a r use Days/week g/occasion g/week A g e at first use (years) No. prior t r e a t m e n t s for d r u g a b u s e
5.6 2.9 1.7 5.1 19.7 0.8
(4.6) ~ ( 1.9) ~ (1.3) ~ (4.1)" (5.2)~ (1.2) a
Route of Administration (%) Intranasal Intravenous Smoked Oral
49 36 14 2
(n (n (n (n
= = = =
43) 30) 12) 2)
55 33 7 5
(n (n (n (n
= = = =
48) 28) 6) 4)
m
m
Other Drug Dependence (%) Alcohol Cannabis Opioids Sedatives
m
m
m
~Standard deviation. *p < .01.
Data Collection
At the intake interview with the cocaine-dependent individuals, the specific questions concerning nicotine and caffeine use were: (1) Do you regularly smoke cigarettes? (2) How many cigarettes per day do you smoke? (3) How many cigarettes do you smoke on days you use cocaine? (4) How many cigarettes do you smoke on days you drink alcohol? (5) Do you drink caffeinated beverages on a regular basis (coffee, tea, or soda)? (6) How many caffeinated beverages per day do you drink (number of cups of coffee or tea/day, or number of sodas/day)? The questions used with the general population sample were similar, except more detailed, plus the number of cigarettes and caffeinated beverages were requested by week rather than by day.
Nicotine and Caffeine Use in Cocaine Dependence
121
Data A n a l y s i s
For both cigarette and caffeine use, subjects were considered regular smokers or caffeine users only if they reported current use of those substances (i.e., at least weekly use during the prior 30 days). Two sample t tests, chi-soeuare analyses, and Fischer's exact tests were performed to test for differences in subject characteristic variables and prevalence of smoking and caffeine use between the cocaine-dependent and general population samples, and among subgroups of the cocaine sample. A Wilcoxon rank-sum test was used to test for differences between groups on number of caffeinated beverages consumed per day; this nonparametric test was used because the dependent measure failed to satisfy the assumptions of parametric tests. A one-way repeated-measures analysis of variance (ANOVA) was conducted to test for differences in self-reported number of cigarettes smoked on days cocaine versus alcohol versus neither drug was used (data for this analysis was available on only 23 persons in the cocaine-dependent group). Newman-Keuls' multiple range tests were used in post-hoc comparisons among those conditions. RESULTS Cigarette U s e
Sixty-five (75%) cocaine-dependent persons reported regular cigarette use and smoked an average of 25.0 (SD = 12.4) cigarettes per day. Prevalence rates did not differ between men (73%) and women (81%). The prevalence of smoking among the cocaine-dependent sample was 3.4 times greater than that of the general population sample (75% vs. 22%), ×2(1, N = 165) = 46.1, p < .001 (Figure 1). Among smokers, the rate of heavy smoking (>- 25 cigarettes/day) tended to be greater in the cocaine-dependent than the general population sample (40% vs. 24%), but this difference was not statistically significant, ×2(1, N = 82) = 1.6, p = .21. An additional analysis was performed to determine if the difference in prevalence of smoking between the cocaine and general population groups was a function of differences in education. Education was collapsed into three categories (i.e., < 12 years, 12-15 years, -> 16 years), and the Mantel-Haenszel chisquare test was used to control for these education strata. Significant differences in prevalence between the cocaine-dependent and general population groups emerged, ×2(1, N = 165) = 22.34, p < .01, indicating that differences in education did not account for the greater prevalence of smoking observed in the cocaine-dependent group. This difference in smoking prevalence was observed across all three education strata (< 12 years: 92% vs. 33%,p < .01; 12-15 years: 69% vs. 37%, p < .01; -> 16 years: 60% vs. 8%, p < .01). Within the cocaine sample, smokers reported using significantly more grams of cocaine per week (5.8 vs. 3.1, p < .01), and nonsignificant trends emerged indicating smokers used cocaine more days per week and initiated cocaine use at an earlier age (Table 2, p. 122). Smokers also were younger, less educated, employed in lower level positions (Hollingshead Scale), and earned less income
PREVALENCE OF C I G A R E T T E S M O K I N G A N D C A F F E I N E USE 100
Z C~
[]
COCAINE DEPENDENT
[]
GENERAL POPULATION
(N--87) (N=78)
80
.< 60 eL C~ eL
40
'~ Z
[
20 r~ eL
CAFFEINE CIGARETTE DRINKERS b SMOKERS a •Significant difference between cocaine-dependent and general population samples (p < .001). I'Significant difference between cocaine-dependent and general population samples (p < .02). F i g u r e 1. Prevalence o f s m o k i n g and caffeine use in the cocaine-dependent versus general population sample.
Table 2.
Cocaine-Dependent Smokers versus Nonsmokers
Age (years) Education (years) Occupation (Hollingshead Scale) Income (S/month)
Smokers (n = 65)
Nonsmokers (n = 22)
29.4 (4.7) 11.8 (1.9) 5.5 (1.3) 744 (707)
32.3 (6.2)** 13.2 (2.6)** 4.2 (1.8)** 1483 (1353)**
Cocaine Years of regular use Days/week g/occasion g/week Age at first use (years) No. prior treatments for drug abuse
6.2 3.1 1.7 5.8 19.1 0.8
Route of Administration Intranasal Intravenous Smoked Oral
% (n) 46 (30) 37 (24) 15 (10) 2 (1)
59 27 9 5
Other Drug Dependence Alcohol Cannabis
57 (37) 29 (19)
46 (10) 41 (9)
(5.0) (2.0) (1.3) (6.8) (4.8) (1.3)
5.0 2.4 1.5 3.1 21.5 0.7
(3.2) (1.5)* (1.4) (2.3)*** (5.9)* (1.1)
% (n) (13) (6) (2) (1)
*p < .10, **p < .05, ***p < .01, for difference between smokers and nonsmokers. 122
Nicotine and Caffeine Use in Cocaine Dependence
123
Table 3. Correlations Between Subject Characteristics and Cocaine Use Variables That Differ Between Smokers and Nonsmokers
Age Education Occupation Income
Grams/Week
Days Used/Week
Age at First Use
-.08 - . 11 .14 -.13
-.09 .06 .07 -.15
.57* -.04 -.29" .12
*p < .01.
than nonsmokers. Correlational analyses were performed to examine the relationship between the cocaine use and sociodemographic variables that differentiated smokers from nonsmokers (Table 3). Age and occupational status (Hollingshead Scale) were significantly correlated with age when cocaine use was initiated. No other significant relationships between sociodemographic and cocaine use variables emerged. Thus, aside from age of initiation of cocaine use, differences in cocaine use observed between smokers and nonsmokers were not accounted for by differences in SES. The prevalence of smoking within the cocaine-dependent sample did not differ between those who were and were not alcohol dependent (79% vs. 70%), ×2(1, N = 87) = 0.87, n.s.; yet, among smokers, a nonsignificant trend emerged suggesting that alcohol-dependent persons were more likely to be heavy smokers than those not alcohol dependent (49% vs. 29%), X2(1, N = 65) = 2.7, p = .10. Within the subsample of 23 cocaine-dependent smokers queried about smoking rates while under the influence of cocaine, alcohol, and sober, subjects reported smoking more cigarettes per day while using cocaine (M = 50.0, SD = 18.2) than alcohol (M = 38.1, SD = 14.5), and more while using either of these substances than sober (M = 24.0, SD = 14.5), F(2, 42) = 41.9, p < .01.
Caffeine Use
Fifty-nine (68%) cocaine-dependent persons reported regular caffeine use and, on the average, drank approximately 4.9 (SD = 3.1) caffeinated beverages per day. Prevalence rates between men (68%) and women (67%) did not differ. The prevalence of caffeine use was less among the cocaine-dependent than the general population sample (68% vs. 83%), ×~(1, N = 165) = 5.3, p < .02 (Figure I). Among caffeine users, those in the cocaine-dependent sample reported drinking significantly more caffeinated beverages per day (M = 4.9, SD = 3.1) than the general population sample (M = 3.3, SD = 2.5), ×2(1,N = 124) = 11.4,p < .001. A Mantel-Haenszel chi-square test controlling for education strata was used to determine if the difference in prevalence of caffeine use between groups was a function of differences in education. A significant difference between the cocaine-dependent and general population group emerged, X2(1, N = 165) =
124
A.I. Budne¥, S.T. Higgins, I.R. Hughes, and W.K. Bickel Table 4.
C o c a i n e - D e p e n d e n t Caffeine Versus N o n u s e r s
Age (years) Education (years) Occupation (Hollingshead Scale) Income (S/month)
Caffeine (n = 59) M (SD)
No Caffeine (n = 28) M (SD)
29.8 (5.2) 12.0 (2.2) 5.2 (1.4) 879 (801)
30.7 (5.7) 12.5 (2.2) 5.1 (1.8) 1057 (1259)
Cocaine
Years of regular use Days/week g/occasion g/week Age at first use No. prior treatments for drug abuse Route of Administration
Intranasal Intravenous Smoked Oral
5.8 (4.3) 2.6 (1.6) 1.8 ( 1.5) 4.6 (5.3) 19.9 (5.3) 0.8 (1.2)
6.1 (4.6) 3.7 (2.2)* 1.4 ( 1.0) 6.3 (7.5) 19.4 (5.0) 0.8 (1.2)
% (n)
% (n)
48 (28) 36 (21) 15 (9) 2 (1)
54 (15) 32 (9) 11 (3) 4 (1)
44 (26) 36 (21 )
75 (21)** 25 (7)
Other Drug Dependence
Alcohol Cannabis *p < .05.
**p < .01, for difference between caffeine users and nonusers.
4.40, p < .04, indicating educational level did not account for the g r e a t e r prevalence o f r e g u l a r caffeine use o b s e r v e d in the general p o p u l a t i o n . Within the c o c a i n e - d e p e n d e n t sample, caffeine users r e p o r t e d using cocaine on fewer days p e r week (M = 2.6, SD = 1.6) than n o n u s e r s (M = 3.7, SD = 2.2; p < .05; Table 4). Caffeine users a n d n o n u s e r s did not differ on any d e m o g r a p h i c variables. However, r e g u l a r caffeine users were less likely to be alcohol d e p e n d e n t t h a n n o n u s e r s (44% vs. 75%), ×2(1, N = 87) = 7.3, p < .01. Nicotine and Caffeine Use
I n the c o c a i n e - d e p e n d e n t sample, the prevalence o f both cigarette s m o k i n g a n d r e g u l a r caffeine use was 51% (n = 44). S m o k e r s (68%) a n d n o n s m o k e r s (68%) were equally likely to be r e g u l a r caffeine users a n d did not differ in the n u m b e r o f caffeinated beverages they d r a n k p e r day (M = 5.0 vs. M = 4.7). In the general p o p u l a t i o n sample, the prevalence o f both s m o k i n g a n d caffeine use was 22% (n = 17), which was significantly lower than the prevalence in the c o c a i n e - d e p e n d e n t sample, X2(1, N = 165) = 14.6, p < .01, reflecting the m u c h lower prevalence o f s m o k e r s in the general population. S m o k e r s (100%), however, were m o r e likely to be r e g u l a r caffeine users t h a n n o n s m o k e r s (79%), ×2(1, N = 78) = 4.34, p < .04, a n d d r a n k a g r e a t e r n u m b e r o f c a f f e i n a t e d beverages p e r day (M = 4.9 vs. M = 2.7, p < .01).
Nicotine and Caffeine Use in Cocaine Dependence
125
DISCUSSION
Nicotine and caffeine use in a sample of cocaine-dependent individuals was compared to use of those substances in a general population sample matched on age and sex. Higher prevalence and daily rates of cigarette smoking were observed in the cocaine-dependent sample. The more than threefold greater prevalence of smoking in this group was not due to the difference in education observed between groups, for this magnitude of difference remained when prevalence was compared across education levels. The' high rate of smoking observed in the cocaine-dependent sample in this study is similar to that reported previously in the alcohol-dependent and other drug-dependent populations (Bobo, 1991; Burling & Ziff, 1988; Kozlowski, Jellinek, & Pope, 1986). Although alcohol dependence within the cocainedependent sample was common (55%), it did not solely account for the high prevalence of smoking, as prevalence did not differ between those who were and were not alcohol dependent. Alcohol dependence among cocaine-dependent persons, however, was associated with heavier smoking, which is consistent with prior reports of heavy smoking in alcoholics (Kozlowski et al., 1986). As has been demonstrated in other drug-dependent populations, cocaine abusers are likely to be at increased risk for smoking-related medical consequences and the medical problems associated with the combination of smoking and heavy alcohol use (e.g., USPHS, 1979). Within the cocaine-dependent group in this study, smoking was associated with diminished SES, that is, smokers tended to be less educated, employed in lesser skilled jobs, and earned less income than nonsmokers. These demographic differences are similar to those observed between smokers and nonsmokers in general population surveys (Marcus, Shopland, Crane, & Lynn, 1989; NIDA, 1990; Pierce, Fiore, Novomy, Hatziandreu, & Davis, 1989). This is an interesting observation suggesting that whatever variables are associated with rates of smoking prevalence among SES groups, that relationship is not obfuscated by cocaine dependence. The greater quantity and more frequent use of cocaine seen in cigarette smokers in this study merits further study as it could have implications for the etiology and treatment of cocaine dependence. SES factors generally were not related to cocaine-use variables, suggesting that the heavier cocaine use observed in the smokers was not accounted for by the SES differences between groups. The finding that smoking was related to an earlier onset of cocaine use is consistent with the notion that cigarettes are a "gateway" substance (Henningfield et al., 1990). This relationship is underscored by the findings that earlier onset is a robust marker of severity of drug dependence and high rates of depressive disorders (Kleinman et al., 1990; Robins & Przybeck, 1985). Age of subject and occupational status were positively correlated with age of onset of cocaine use suggesting that the difference in age of onset between groups may be partially accounted for by the demographic factors that differed between smokers and nonsmokers. Evidence suggesting that cocaine use directly impacts rates of cigarette smok-
126
A.I. Budney, $.T. I-li~ins, I.R. Hughes, and W.K. Bickel
ing was observed in this study. Cocaine-dependent subjects reported using almost threefold more cigarettes on days they used cocaine and almost twofold more on days they used alcohol as compared to days they were sober. Although these data are correlational, and causality cannot be assessed, the increase in smoking is consistent with laboratory studies indicating that acute administration of cocaine, d-amphetamine, and alcohol increase smoking rates (Griffiths, Bigelow, & Liebson, 1976; Henningfield & Griffiths, 1981; Low et al., 1984; Nemeth-Coslet et al., 1986). In terms of treatment, it is only recently that the high prevalence and adverse implications of cigarette smoking in drug- and alcohol-dependent individuals has begun to be addressed (Bobo & Gilchrist, 1983; Burling, Marshall, & Seidner, 1991; Hughes, in press; Kozlowski, Skinner, Kent, & Pope, 1989). Although no empirical evidence indicates that smoking cessation negatively affects drug or alcohol treatment, few clinicians offer assistance or even suggest smoking cessation (Bobo & Gilchrist, 1983)..Clinical trials are needed to determine the most effective time to intervene on cigarette smoking with persons seeking treatment for other drug use, including cocaine, and whether such interventions influence treatment outcome. Caffeine use among the cocaine-dependent sample was less prevalent than the general population sample, but daily rates of caffeine consumption were greater. Moreover, among the cocaine-dependent group, caffeine use was less prevalent in those who also were alcohol dependent, and no differences in caffeine use were observed between smokers and nonsmokers. These findings are difficult to interpret in light of previous research examining the use of caffeine and other abused substances. Research on the relationship between alcohol dependence and caffeine use suggests that alcoholics in recovery consume larger quantities of caffeine than the general or psychiatric population, but it is not clear whether caffeine consumption differs between active alcoholics and the general population (Ayers et al., 1976; Doucette & Willoughby, 1980; Istvan & Matarazzo, 1984; Klatsky et al., 1977; Verinis, 1986). Caffeine use in this study was measured during active cocaine dependence. Although any hypotheses for the observed relationship between caffeine and cocaine use must be considered highly speculative given these data, we offer some possibilities. One explanation for the lower prevalence of caffeine use among cocaine abusers is that some abusers seek to counter cocaine's stimulant effects following a period of use, and thus would be more likely to use a drug with depressant effects, such as alcohol, rather than another stimulant like caffeine. This hypothesis would be consistent with the greater prevalence of alcohol dependence observed in the group that did not use caffeine. Another possibility is that cocaine abusers are less likely to use caffeine because they have an alternative stimulant to use (i.e., cocaine), which would be consistent with the aforementioned drug-discrimination research in nonhumans showing that caffeine can substitute for cocaine (Gauvin et al., 1990; Harland et al., 1989). A third hypothesis is that caffeine use may be associated with a relatively more stable life style (e.g., drink prior to work, during coffee break or lunch, after dinner, etc.), which would suggest greater prevalence of use in the general population sample. Although no differences in SES factors included in
Nicoline and Caffeine Use in Cocaine Dependence
127
this study were found to support this notion, the greater rate of alcohol dependence in noncaffeine users may be associated with a more chaotic life style. Among those who use caffeine, the greater daily rate of caffeine use observed in cocaine abusers compared to the general population may simply indicate their tendency to abuse substances, stimulants in particular. Interestingly, within the cocaine-dependent sample, caffeine users reported using cocaine on fewer days per week. As discussed before, these findings suggest that caffeine may substitute for cocaine in some individuals. If such a relationship could be substantiated in prospective studies in humans (e.g., caffeine use decreased the frequency of cocaine use), it would have important treatment implications. Considering the positive relationship observed between caffeine and cigarette smoking in the matched controls in this study and other populations in prior studies (Istvan & Matarazzo, 1984), the lack of a relationship between caffeine use and cigarette smoking within the cocaine-dependent sample was surprising. Data on caffeine use in abusers of substances other than alcohol or cigarettes, to our knowledge, has not been reported. Thus, whether the caffeine use pattern observed in this cocaine-dependent sample is consistent with patterns observed in other drug-dependent populations is unknown. The findings from this study should be interpreted cautiously considering its retrospective nature, the reliance on self-reports (e.g., cup size for caffeine use was not reported), and the variability in the method of data collection between the cocaine-dependent and general population samples (e.g., in-person interview vs. phone interview; James, Bruce, Lader, & Scott, 1989; Kennedy, yon Molte, Harmatz, Engelhardt, & Greenblatt, 1991; Lelo, Miners, Robson, & Birkett, 1986; Schreiber et al., 1988). Additional prospective studies using more standardized methods of data collection are needed to further our understanding of the relationships among nicotine, caffeine, and cocaine use. In summary, the high prevalence of nicotine use (i.e., cigarette smoking) and moderate prevalence of caffeine use among cocaine-dependent persons, and the significant relationship between use of those substances and patterns of cocaine use observed in this study warrant further examination. The observed relationships among the uses of these substances have implications not only for increased risk for adverse medical consequences, but may be important to issues such as initiation and maintenance of cocaine use, severity or patterns of use, response to treatment, and probability for relapse. Although this study did not directly examine the influence of nicotine and caffeine on cocaine use, these results suggest that uni- and bidirectional interactions among these drugs may occur. REFERENCES
Ayers, J., Ruff, C.F., & Templer, D.I. (1976). Alcoholism, cigarette smoking, coffee drinking and extroversion.Journal of Studies on Alcohol, 37, 983-985. Bobo, J.K. (1991). Nicotine dependence and alcoholism epidemiology and treatment. Journal of Psychoactive Drugs, 21, 323-328. Bobo,J.K., & Gilchrist, L.D. (1983). Urging the alcoholicto quit smoking cigarettes. Addictive Behaviors, 8, 297-305.
128
A.I. Budney, S.T. Higgins, I.R. Hughes, and W.K. Bickel
Budney, A.J., Higgins, S.T., Delaney, D.D., Kent, L., & Bickel, W.K. (1991). Contingent reinforcement of abstinence with individuals abusing cocaine and marijuana.Journal of Applied Behavior Analysis, 24, 657-665. Burling, T.A., Marshall, G.D., & Seidner, A.L. (1991). Smoking cessation for substance abuse inpatients. Journal of Substance Abuse, 3, 269-276. Burling, T.A., &, Ziff, D.C. (1988). Tobacco smoking: A comparison between alcohol and drug abuse inpatients. Addictive Behaviors, 13, 185-190. Cregler, L.L., & Mark, H. (1986). Cardiovascular dangers of cocaine abuse. American Journal of Cardiology, 57, 1185-1186. Derlet, R.W., Tseng, J.C., & Albertson, T.E. (1992). Potentiation of cocaine and d-amphetamine toxicity with caffeine. American Journal of Emergency Medicine, 10, 211-216. Doucette, S.R., & Willoughby, A. (1980). Relevance of caffeine symptomatology to alcohol rehabilitation efforts. US Navy Medicine, 71, 6-13. Ettinger, N.A., & Albin, R.J. (1989). A review of the respiratory effects of smoking cocaine. American Journal of Medicine, 87, 664-668. Evans, E.B., & Wenger, G.R. (1990). The effects of cocaine in combination with other drugs of abuse on schedule-controlled behavior in the pigeon. Pharmacology, Biochemistry, & Behavior, 37, 349357. Foltin, R.W., & Fischman, M.W. (1991). Smoked and intravenous cocaine in humans: Acute tolerance, cardiovascular and subjective effects. Journal of Pharmacology and Experimental Therapeutics, 257, 247-261. Gauvin, D.V., Criado, J.R., Moore, K.R., & Holloway, F.A. (1990). Potentiation of cocaine's discriminative effects by caffeine: A time-effect analysis. Pharmacology, Biochemistry, & Behavior, 36, 195-197. Gawin, F.H., & Kleber, H.D. (1990). Abstinence symptomatology and psychiatric diagnosis in cocaine abusers: Clinical observations. Archives of General Psychiatry, 43, 107-113. Gilbert, R.M. (1976). Caffeine as a drug of abuse. In R.J. Gibbons, Y. Israel, H. Kalant, R.E. Popham, W. Schmidt, & R.G. Smart (Eds.), Research advances in alcohol and drug problems (Vol. 3). New York: Wiley. Griffiths, R.R., Bigelow, G.E., & Liebson, I. (1976). Facilitation of human tobacco self-administration by ethanol: A behavioral analysis.Journal of the Experimental Analysis of Behavior, 25, 279-292. Griffiths, R.R., & Woodsen, P.P. (1989). Reinforcing effects of caffeine in humans.Journal of Phar-
macology and Experimental Therapeutics, 246, 1-8. Hale, K.L., Hughes, J.R., Oliveto, A.H., Helzer, J.E., Higgins, S.T., Bickel, W.K., & Cottler, L.B. (1993). Nicotine dependence in a population-based sample. In L. Harris (Ed.), Problems of drug dependence 1992 NIDA researchmonograph (No. 132, p. 181). Washington, DC: U.S. Government Printing Office. Harland, R.D., Gauvin, D.V., Michaelis, R.C., Carney, J.M., Seale, T.W., & Holloway, F.A. (1989). Behavioral interaction between cocaine and caffeine: A drug discrimination analysis in rats. Pharmacology, Biochemistry, & Behavior, 32, 1017-1023. Henningfield,J.E., Clayton, R., & Pollin, W. (1990). Involvement of tobacco in alcoholism and illicit drug use. British Journal of Addiction, 85, 279-292. Henningfield, J.E., & Griffiths, R.R. (1981). Cigarette smoking and subjective response: Effects of d-amphetamine. Clinical Pharmacology and Therapeutics, 30, 497-505. Higgins, S.T., Bickel, W.K., Hughes, J.R., Lynn, M., & Capeless, M.A. (1990). Effects of intranasal cocaine on human learning, performance, and physiology. Psychopharmacology, 102, 451-458. Higgins, S.T., Delaney, D.D., Budney, A.J., Bickel, W.K., Hughes, J, Foerg, F., & Fenwick, J. (1991). A behavioral approach to achieving initial cocaine abstinence. American Journal of Psychiatry, 148, 1218-1224. Higgins, S.T., Rush, C.R., Bickel, W.K., Hughes, J.R., & Capeless, M.A. (1992). The effects of cocaine and alcohol alone and in combination on human learning and performance. Journal of the Experimental Analysis of Behavior, 58, 87-105. Horger, B.A., Wellman, P.J., Morien, A., Davies, B.T., & Schenk, S. (1991). Caffeine exposure sensitizes rats to the reinforcing effects of cocaine. NeuroReport, 2, 53-56. Hughes, J.R. (in press). Treatment of smoking cessation in smokers with past alcohol/drug problems.
Journal of Substance Abuse Treatment.
Nicotine and Caffeine Use in Cocaine Dependence
129
Hughes, J.R., Hatsukami, D.K., Mitchell, J.E., & Dahlgren, L.A. (1986). Prevalence of smoking among psychiatric outpatients. AmericanJournal of Psychiatry, 143, 993-997. Hughes, J.R., Higgins, S.T., Bickel, W,K., Hunt, W.K., Fenwick,J.W., Gulliver, S.B., & Mireauh, G.C. (1991). Caffeine self-administration, withdrawal, and adverse effects among coffee'drinkers. Archives of General Psychiatry, 48, 611-617. Hughes, J.R., Oliveto, A.H., Bickel, W.K., Helzer, J.E., Higgins, S.T., & Cottler, L.B. (1993). Indicators of caffeine dependence in a population-based sample. In L. Harris (Ed.), Problemsof drug dependence 1992. NIDA research monograph (No. 132, p. 194). Washington, DC: U.S. Government Printing Office. Istvan, J., & Matarazzo, J.D. (1984). Tobacco, alcohol, and caffeine use: A review of their relationships. PsychologicalBulletin, 95, 301-326. James, J.E. (1991). Caffeine and health. London: Academic. James, J.E., Bruce, M.S., Lader, M.H., & Scott, N.R. (1989). Self-report reliability and symptomatology of habitual caffeine consumption. British Journal of Clinical Pharmacology, 27, 507-514. Kennedy, J.S., yon Molte, L.L., Harmatz, J.S., Engelhardt, N., & Greenblatt, D.J. (1991). Validity of self-reports of caffeine use. Journal of Clinical Pharmacology, 31,677-680. Klatsky, A.L., Friedman, G.D., Siegelauh, A.B., & Gerard, M.J. (1977). Alcohol consumption among white, black, or Oriental men and women: Kaiser-Permanente muhiphasic health examination data. AmericanJournal of Epidemiology, 105, 311-323. Kleinman, P.H., Miller, A.B., Millman, R.B., Woody, G.E., Todd, T., Kemp, J , & Lipton, D.S. (1990). Psychopathology among cocaine abusers entering treatment. Journal of Nervous and Mental Disease, 178, 442-447. Kozlowski, L.T., Jellinek, L.C., & Pope, M.A. (1986). Cigarette smoking among alcohol abusers: A continuing and neglected problem. CanadianJournal of Public Health, 77, 205-207. Kozlowski, L.T., Skinner, W., Kent, C., & Pope, M.A. (1989). Prospects for smoking treatment in individuals seeking treatment for alcohol and other drug problems. Addictive Behaviors, 14, 273-278. Kreek, M.J. (1987). Multiple drug abuse patterns and medical consequences. In H.Y. Meltzer (Ed.), Psychopharmacology: The third generation of progress. New York: Raven. Lelo, A., Miners, J.O., Robson, R., & Birkett, D.J. (1986). Assessment of caffeine exposure: Caffeine content of beverages, caffeine intake, and plasma concentrations of methylxanthines. Clinical Pharmacology and Therapeutics, 39, 54-59. Logan, L., Carney, J.M., Holloway,F.A., &Seale, T.W. (1988). Effects of caffeine, cocaine, and their combination on fixed-interval behavior in rats. Pharmacology, Biochemistry, & Behavior, 33, 99-104. Low, R.B., Jones, M., Carte, B., & Cadoret, R.J. (1984). The effect of d-amphetamine and ephedrine on smoking attitude and behavior. Addictive Behaviors, 9, 335-345. Marcus, A.C., Shopland, D.R., Crane, L.A., & Lynn, W.R. (1989). Prevalence of cigarette smoking in the United States: Estimates from the 1985 current population survey.Journal of the National Cancer Institute, 6, 409-414. Miller, N.S., Gold, M.S., Belkin, B.M., & Klahr, A.L. (1989). Family history and diagnosis of alcohol depSn ence in cocaine dependence. Psychiatry Research, 29, 113-121. Misra, A.L., ~ l l a m a n i , N.L., & Pontani, R.B. (1986). Effect of caffeine on cocaine locomotor stimulant activity in rats. Pharmacology, Biochemistry, & Behavior, 24, 761-764. National Institute on Drug Abuse (NIDA). (1990). National household survey: Main findings 1988. Rockville, MD: U.S. Government Printing Office. Nemeth-Coslet, R., Henningfield, J., Katz, J., & Goldberg, S. (1986). Effect of cocaine on rate of cigarette smoking. Pharmacology, Biochemistry & Behavior, 25, 300. Pierce, J.P., Fiore, M.C., Novotny, T.E., Hatziandreu, E.J., & Davis, R.M. (1989). Trends in cigarette smoking in the United States: Educational differences are increasing. Journal of the American Medical Association, 261, 56-60. Robins, L.N., & Przybeck, T.R. (1985). Age of onset of drug use as a factor in drug and other disorders. In C.L. Jones & R.J. Battjes (Eds.), Etiology of drug abuse: Implicationsfor prevention. Washington, DC: U.S. Government Printing Office. Rush, C.R., Higgins, S.T., Bickel, W.K., & Hughes, J.R. (1992). The effects of caffeine and alcoholalone, and in combination, on human learning and performance. Unpublished manuscript, University of Vermont, Department of Psychiatry, Burlington.
130
A.J. Budney, S.T. Higgins, J.R. Hughes, and W.K. Bickel
Schenk, S., Horger, B.A., & Snow, S. (1990). Caffeine preexposure sensitizes rats to the motor activating effects of cocaine. Behavioural Pharmacology, 1,447-451. Schnoll, S.H., Daghestani, A.N., Karrigan, J., Kitchen, S.B., & Hansen, T. (1985). Characteristics of cocaine users in treatment. In L.S. Harris (Ed.), Problems of drug dependence, 1985, NIDA research monograph 67. Washington, DC: U.S. Government Printing Office. Schreiber, G.B., Maffeo, C.E., Robins, M., Masters, M.N., & Bond, A.P. (1988). Measurement of coffee and caffeine intake: Implications for epidemiologic research. Preventive Medicine, 17, 280-294. U.S. Public Health Service (USPHS). (1979). Smoking supplement of the national health interview survey. Washington, DC: U.S. Government Printing Office. Verinis, J.S. (1986). Caffeine use in the recovering alcoholic. Alcohol Health and Research World, 2, 6479. Weiss, R.D., Mirin, S.M., Griffin, M.L., & Michael, J.L. (1988). Psychopathology in cocaine abusers. Journal of Nervous and Mental Disease, 176, 719-725. Wesnes, K., & Warburton, D.M. (1983). Smoking, nicotine and human performance. Pharmacological Therapeutics, 21, 189-208.