143
Drug and Alcohol Dependence, 30 (1992) 143- 149 Elsevier Scientific Publishers Ireland Ltd.
The scientific/clinical response to the cocaine epidemic: MEDLINE search of the literature
a
Alan J. Budney, Stephen T. Higgins, John R. Hughes and Warren K. Bickel Human Behavioral Pharmacology Labwatory, Department of Psychiatry University of Vermont, Burlington, VT
05401
(U.S.A.)
(Accepted January 7, 1992)
Index Medicus (1966 - 1990) was searched to quantify and characterize the scientific/clinical community’s response to the cocaine epidemic. The rate of growth in the cocaine literature was compared with the rate of growth in the heroin and marijuana literatures in the 1960s and 1970s. Articles on cocaine increased dramatically over the past 7 years suggesting a clear response from the scientific/clinical community to the public health problems presented by the cocaine epidemic. That literature spans a wide range of areas addressing many scientific and health-care issues. This increase in cocaine citations is similar to that which occurred previously in response to use of heroin and marijuana. Key woro!s: cocaine; heroin; marijuana; review; treatment;
Introduction One to two million persons in the United States are dependent on cocaine (National Institute on Drug Abuse (NIDA), 1990a; Committee on the Judiciary, 1990). Although recent data indicate a trend toward a reduction in recreational use, the number of persons using cocaine once a week or more increased 33% from 1985 to 1988 (MDA, 1989). This information suggests that cocaine dependence will remain a major public health problem during the 1990s. Some have voiced concern that the scientific community in general and the clinical community in particular have not responded adequately to the cocaine epidemic (e.g. Congressional General Accounting Office, 1990; Lerner, 1989). Those concerns, however, may result from
Correspondace to: S.T. Higgins, Human Behavioral Pharmacology Laboratory, Department of Psychiatry, University of Vermont, 38 Fletcher Place-Ira Allen School, Burlington, VT 05401, U.S.A. 0376-8716/92/$05.00 0 1992 Elsevier Scientific Publishers Printed and Published in Ireland
perinatal effects; cardiac effects
frustration caused by the lack of clear demonstrations of effective treatments for cocaine dependence (Gawin and Kleber, 1987), rather than an inadequate response to the problem (Higgins, 1990). The obvious importance of scientific information concerning cocaine dependence and attendant problems to making educated decisions concerning treatment, medical care, research development, and allocation of funding, calls for an evaluation of those concerns. Federal funding for cocaine research certainly reflects an increased concern for the problems associated with the growing cocaine problem (MDA, 1990b). The purpose of the present paper is to quantify and characterize the scientific community’s response to the cocaine epidemic in general, with particular attention given to selected clinical and medical issues. We wanted to determine how the medical literature changed in relation to increased cocaine use in the United States during the 1980s. In order to have a reference against which to compare the rate of growth of the cocaine literature, the growth in Ireland Ltd.
144
the literature that occurred in response to the heroin and marijuana ‘epidemics’ of the late 1960s and the early-mid 1970s was also assessed, That comparison also provides information that may be helpful in predicting the future course of growth of the cocaine literature. Method
Year by year MEDLINE (the computerized Index Medicus) searches from 1966 (the first year it was available on-line) to 1990 were conducted. The first search used the index term ‘cocaine’, which provides information on all articles dealing with cocaine including those on ‘crack’. ‘Cocaine’ was cross-referenced with four categories to provide a broad overview of current cocaine research. Those categories were: (1) treatment (index terms: ‘therapy’, ‘drug therapy’, or ‘rehabilitation’), (2) ‘review’, (3) ‘human’ and (4) ‘non-human.’ Two categories concerning important medical consequences of cocaine use were also cross-referenced with cocaine. Those categories were: (1) perinatal effects (index term: ‘pregnancy’) and (2) cardiac effects (index term: ‘heart disease’). Finally, for 1990 only, the cocaine treatment category was cross-referenced with research studies (index terms: ‘comparative study’ and ‘clinical trials’) to provide an indicator of how many treatment citations were research reports. A second set of MEDLlNE searches was conducted on heroin (index terms: ‘heroin dependence’ or ‘diacetylmorphine’) and marijuana (index terms: ‘marijuana abuse’, ‘marijuana smoking’, or ‘cannabis’). Those index terms were used for heroin and marijuana because the unitary terms ‘marijuana’ and ‘heroin’, unlike ‘cocaine’, are not available as search terms in MEDLINE. These searches, however, provide an equivalent subset of articles across drugs and permit a direct comparison of total citations. We cross-referenced those heroin and marijuana terms with the treatment category using the same index terms cross-referenced with cocaine. A subset of the cocaine citations (i.e., citations on reviews, cardiac effects, and perinatal
effects) were subjected to a content analysis by reviewing the title (and abstract if necessary) of each article (Budney et al., 1990). All of those citations (n = 708) were verified indicating that the citations were categorized accurately. A number of citations appeared in more than one category, and the articles varied in quality within and across categories. Results
Cocaine citations The MEDLINE search revealed a total of 5410 cocaine citations from 1966 to 1990. Total cocaine citations per year increased 4-fold between 1984 and 1990 (Fig. 1). The largest l-year increase in absolute number of total citations occurred between 1988 and 1989. A similar pattern emerged across all categories crossreferenced with cocaine, that is, treatment, cardiac effects, perinatal effects, reviews, human and non-human (Figs. 1 and 2). Increases across categories between 1984 and 1990 ranged 2.7 48.5-fold with an average increase of 12-fold. This period of rapid growth of cocaine citations lagged approximately 5-7 years behind the rapid increase in prevalence of cocaine use (Fig. 3). One noteworthy pattern was that of citations concerning humans vs. non-humans (Fig. 2). The number of cocaine citations concerning nonhumans was always greater than those with humans until 1985 when that pattern reversed and a growing discrepancy between the two has been evident since that time. The search of 1990 treatment citations revealed that only 11 of the 96 (11.4%) were research studies. Cocaine, heroin and marijuana In addition to cocaine citations, Fig. 1 also shows total citations and treatment citations for heroin and marijuana between 1966 and 1990. Citations increased dramatically for each drug during certain 7 -g-year periods (cocaine: 1984 - 90; heroin: 1968 - 75; marijuana 1966 75). To compare the rate of increase during those time periods, regression analyses were
145
TREATMENT
TOTAL COCAINE 7Wr
g
HEROIN
7w
600
600
F
Gf k
500
3
400
3
300
3w
2W
2w
loo
loo
$ 2
0
86
70
74
76
62
66
0
90
66
70
74
76
62
66
90
MARIJUANA
7M)-
700 r
1
6W
-
600
500
-
500
400-
400 I
300
-
300
200
-
200 1
loo
-
100 t
Ol 66
70
OS 66
90
70
74
76
62
66
YEARS Fig. 1. The number
of total citations
and treatment
citations
for cocaine,
heroin and marijuana
as a function
of year.
90
146
CARDIAC EFFECTS 120
PERINATAL EFFECTS
COCAINE
r
60
0
66
70
74
78
82
86
-
0
90
66
70
74
78
82
86
HUMAN VS. NONHUMAN
REVIEWS COCAINE
7
r
HUMAN
66
70
74
78
90
82
86
90
70
74
70
82
86
90
YEARS Fig. 2. The number of cocaine citations in four categories as a function of year. Note the different range on the y axis for the human-non-human panel.
conducted on citations during those specific years for each drug. Equality of slopes was tested using t-tests and Bonferroni adjustments to control for type I error rates due to multiple comparison tests. No differences between drugs in the slopes for total citations emerged, indicating that the rate of increase was comparable across them. The slope for heroin treatment citations (mean increase = 47.3 articles/year) was greater than the slopes for cocaine treatment citations (mean increase = 13.5 articles/year) (P < 0.05) and marijuana treatment citations (mean increase = 3.7 artitles/year) (P < 0.05). The slope for cocaine treatment citations was greater than the slope for marijuana citations (P < 0.05).
Discussion The MEDLlNE search on cocaine clearly documents that the scientific/clinical literature on this topic is growing, particularly over the past ‘7 years. The extant literature spans a wide range of areas addressing many basic science, health-care, and treatment issues related to coCaine use. The escalation of cocaine use and cocaine-related adverse consequences beginning in the late 1970s has been documented by various sources (e.g., Cocaine client admissions (NIDA, 1987); Drug Abuse Warning Network (NIDA, 199Oc); NIDA Household Surveys (NIDA, 1988,199Oa)). Given that publication of research results is expected to lag a number of
147
8-
COCAINE PREVALENCE
RATE
CITATIONS
n
Y4
I
I
I
I
I
I
I
76
78
80
82
84
86
88
n
90”
YEARS Fig. 3. The prevalence of cocaine use and the number of total cocaine citations as a function of year. The prevalence estimates were taken from NIDA (1991), and represent estimates of the percentage of persons age 18 - 25 in the general population who reported cocaine use during the 30 days prior to the survey.
years behind the recognition of a problem (i.e., funding must be allocated, funding proposals submitted and evaluated, research conducted, articles submitted and reviewed for publication), the present results suggest that the increase in cocaine articles temporally followed the cocaine epidemic in a relatively timely fashion. Furthermore, a comparison of the number of cocaine citations during this time period with citations concerning heroin and marijuana during the same time period (Fig. 1) indicates that the increase in cocaine articles was not merely a function of a general increase in drug abuse research. Cocaine citations increased dramatically, while heroin and marijuana citations increased only slightly over this time period. This data suggests that a substantial proportion of the increased funding available for drug abuse research since 1985 (NIDA, 1990b) was allocated to cocaine research projects and that the increase in cocaine citations was a function of that funding. Indeed, from 1986 to 1991, NIDA increased extramural funding for cocaine
research more than 11-fold (3.4 -39.5 million dollars), reflecting a change from cocaine research accounting for 6% of the NIDA’s research budget in 1986 to 17% in 1990 (NIDA, 1990b; NIDA 1991, pers. commun.). Therefore, the increase in scientific attention to cocaine could be interpreted as the scientific community responding to increased cocaine use by influencing federal funding agencies, or conversely, the scientific community being influenced by funding agencies. The initiation of increased funding for cocaine research in 1985 could be considered a lack of responsivity by funding agencies given that peak cocaine prevalence rates occurred in 1979. NIDA’s research budget, however, was relatively small until 1985 when funding for drug abuse research in general began to increase substantially (NIDA, 1990b). Thus, when funding became available, it was expediently allocated for cocaine research, and a rapid escalation of scientific publications followed. Comparisons of the increases observed in
148
cocaine citations during the past 7 years with the increases observed in heroin and marijuana citations in the late 1960s and early-mid 1970s indicate the response to the current cocaine epidemic is consistent with the historic response to other drug epidemics in the United States. The rate of increase in total citations did not differ among drugs during those comparison years. Some differences in rate and absolute number of treatment citations across drugs emerged. Heroin treatment citations appeared at a greater rate and number than cocaine or marijuana treatment citations; this likely reflects research conducted on methadone treatment for heroin dependence. For instance, the large increase in heroin citations observed in 1975 (Fig. 1) resulted from 216 citations entered into Index Medicus from a single conference on the use of methadone in the treatment of heroin dependence. Unlike heroin dependence, an agreed upon pharmacotherapy (methadone) does not exist for cocaine or marijuana dependence. Also noteworthy, the rate of increase and absolute number of marijuana treatment citations was lower than cocaine or heroin, suggesting that scientific attention to a drug is influenced by the severity of consequences associated with abusing the drug. Moreover, total and treatment citations for marijuana peaked in 1976 prior to the peak use years of 1977 to 1979 (NIDA, 199Oa). In contrast, cocaine citations peaked following peak prevalence years (accurate data on peak prevalence of heroin use was unavailable). These findings suggest that scientific attention to a drug is influenced by factors other than prevalence alone. The rapid growth periods for heroin and marijuana citations lasted approximately 8 and 10 years, respectively, after which the number of citations for both drugs plateaued, declined, and then stabilized at that lower level (Fig. 1). This pattern suggests that a similar trend may occur with cocaine citations, and that the plateau period may occur during the next few years. A number of limitations of this computer search exist. First, MEDLlNE does not cover all journals devoted to drug abuse and certainly not all articles on this topic. Therefore, the number
of citations and rates of growth reported in this review should be considered conservative estimates. Second, MEDLINE adds journals to its search list periodically. Increases in citations across years can be influenced by those additions. The comparison of cocaine citations to heroin and marijuana citations during the same time periods, however, illustrates that the increase in cocaine citations was not simply a byproduct of the inclusion of new journals on drug abuse. Third, although specific areas were searched, (e.g., treatment), this search did not provide information concerning what types of articles exist within each area. This could be misleading. For example, although treatment articles appear plentiful, the search of treatment-research citations conducted in the present study and a careful review of the cocaine treatment literature (Budney and Higgins, in press) indicates that only a few controlled treatment studies have been reported. The reader is referred to Johanson and Fischman (1989) for a comprehensive review and evaluation of specific areas of cocaine research. In summary, it is apparent that cocaine and its attendant problems have received an increasing amount of attention in the scientific/clinical literature over the past two decades, with the most dramatic escalation occurring over the past 7 years. Although there is firm evidence that the scientific/clinical community has responded to the current cocaine epidemic, a great deal more needs to be done in many cocaine-related problem areas. For example, research on the development of treatments for cocaine dependence is sorely needed. Those needs not withstanding, this increase in attention to cocaine is similar to what occurred during prior epidemics with other abused drugs. It is important that the work that has already been done is not overlooked and that this knowledge base be used to guide future research and clinical interventions. Acknowledgements Supported by the National Institute on Drug Abuse grant R18DA06113 awarded to the second author (Dr. Higgins) and National Insti-
149
tute on Drug Abuse training grant T32DA07242. We thank Catherine Goddard, Dana Medical Library, for help with the literature searches. References Budney, A.J., Delaney, D.D. and Higgins, S.T. (1990) Trends in the scientific literature on cocaine: 1966 - 1989. Paper presented at the meeting of the American Psychological Association, Boston, MA. Budney A.J. and Higgins, S.T. Psychological treatments for cocaine dependence. In: Encyclopedia of Drugs and Alcohol (Jaffe, J., ed.) in press. Committee on the Judiciary, United States Senate (1990) Hard-core cocaine addicts: Measuring and fighting the epidemic. (Publication No. 552 - 070 - 08156 - 9) U.S. Government Printing Office, Washington, DC. Congressional General Accounting Office (1990) Drug abuse: Research on treatment may not address current needs (HRD-90-114). U.S. General Accounting Office, Washington DC. Gawin, F.H. and KIeber, H. (1987) Issues in cocaine abuse treatment research. In Cocaine: Clinical and Biobehavioral Aspects (Fisher, S., Raskin, A. and Uhlenhuth, E.H., eds.), pp. 174- 192. Oxford University Press, New York. Higgins, S.T. (1990) Trends in the scientific literature on cocaine. Am. J. Med. 89, p. 544. Johanson, C.E. and Fischman, M.W. (1989) The pharmacology of cocaine related to its abuse. Pharmacol. Rev. 41, 3-52. Lerner, W.D. (1989) Cocaine abuse and acquired im-
munodeficiency syndrome: A tale of two epidemics. Am. J. Med. 87, 661-663. National Institute on Drug Abuse (1991) Statistics from the National Household Survey on Drug Abuse. In: NIDA Notes, Vol. 6 (National Institute on Drug Abuse, Ed.), pp. 31. (DHHS Publications No. ADM 90-1488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1990a) National household survey on drug abuse: Main findings 1988 (DHHS Publications No. ADM 90-1682), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (199Ob) NIDA’s response to the GAO report. In: NIDA Notes, V.5 (National Institute on Drug Abuse, Ed.), pp. 3-4. (DHHS Publications No. ADM 90 - 1488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (199Oc) Data from the Drug Abuse Warning Network (DAWN) Semiannual report, trend data through January-June 1989. (DHHS Publications No. ADM 90 - 1664), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1989) Household survey. In: NIDA Notes, V.4 (National Institute on Drug Abuse, Ed.), pp. 42-43. (DHHS Publications No. ADM 891488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1987) Cocaine client admissions 1976-1985. (DHHS Publications No. ADM 87 - 1528) U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1988) National household survey on drug abuse: Main findings 1985 (DHHS Publications No. ADM 88 - 1586) U.S. Government Printing Office, Washington, DC.
Drug and Alcohol Dependence, 30 (1992) 143- 149 Elsevier Scientific Publishers Ireland Ltd.
The scientific/clinical response to the cocaine epidemic: MEDLINE search of the literature
a
Alan J. Budney, Stephen T. Higgins, John R. Hughes and Warren K. Bickel Human Behavioral Pharmacology Labwatory, Department of Psychiatry University of Vermont, Burlington, VT
05401
(U.S.A.)
(Accepted January 7, 1992)
Index Medicus (1966 - 1990) was searched to quantify and characterize the scientific/clinical community’s response to the cocaine epidemic. The rate of growth in the cocaine literature was compared with the rate of growth in the heroin and marijuana literatures in the 1960s and 1970s. Articles on cocaine increased dramatically over the past 7 years suggesting a clear response from the scientific/clinical community to the public health problems presented by the cocaine epidemic. That literature spans a wide range of areas addressing many scientific and health-care issues. This increase in cocaine citations is similar to that which occurred previously in response to use of heroin and marijuana. Key woro!s: cocaine; heroin; marijuana; review; treatment;
Introduction One to two million persons in the United States are dependent on cocaine (National Institute on Drug Abuse (NIDA), 1990a; Committee on the Judiciary, 1990). Although recent data indicate a trend toward a reduction in recreational use, the number of persons using cocaine once a week or more increased 33% from 1985 to 1988 (MDA, 1989). This information suggests that cocaine dependence will remain a major public health problem during the 1990s. Some have voiced concern that the scientific community in general and the clinical community in particular have not responded adequately to the cocaine epidemic (e.g. Congressional General Accounting Office, 1990; Lerner, 1989). Those concerns, however, may result from
Correspondace to: S.T. Higgins, Human Behavioral Pharmacology Laboratory, Department of Psychiatry, University of Vermont, 38 Fletcher Place-Ira Allen School, Burlington, VT 05401, U.S.A. 0376-8716/92/$05.00 0 1992 Elsevier Scientific Publishers Printed and Published in Ireland
perinatal effects; cardiac effects
frustration caused by the lack of clear demonstrations of effective treatments for cocaine dependence (Gawin and Kleber, 1987), rather than an inadequate response to the problem (Higgins, 1990). The obvious importance of scientific information concerning cocaine dependence and attendant problems to making educated decisions concerning treatment, medical care, research development, and allocation of funding, calls for an evaluation of those concerns. Federal funding for cocaine research certainly reflects an increased concern for the problems associated with the growing cocaine problem (MDA, 1990b). The purpose of the present paper is to quantify and characterize the scientific community’s response to the cocaine epidemic in general, with particular attention given to selected clinical and medical issues. We wanted to determine how the medical literature changed in relation to increased cocaine use in the United States during the 1980s. In order to have a reference against which to compare the rate of growth of the cocaine literature, the growth in Ireland Ltd.
144
the literature that occurred in response to the heroin and marijuana ‘epidemics’ of the late 1960s and the early-mid 1970s was also assessed, That comparison also provides information that may be helpful in predicting the future course of growth of the cocaine literature. Method
Year by year MEDLINE (the computerized Index Medicus) searches from 1966 (the first year it was available on-line) to 1990 were conducted. The first search used the index term ‘cocaine’, which provides information on all articles dealing with cocaine including those on ‘crack’. ‘Cocaine’ was cross-referenced with four categories to provide a broad overview of current cocaine research. Those categories were: (1) treatment (index terms: ‘therapy’, ‘drug therapy’, or ‘rehabilitation’), (2) ‘review’, (3) ‘human’ and (4) ‘non-human.’ Two categories concerning important medical consequences of cocaine use were also cross-referenced with cocaine. Those categories were: (1) perinatal effects (index term: ‘pregnancy’) and (2) cardiac effects (index term: ‘heart disease’). Finally, for 1990 only, the cocaine treatment category was cross-referenced with research studies (index terms: ‘comparative study’ and ‘clinical trials’) to provide an indicator of how many treatment citations were research reports. A second set of MEDLlNE searches was conducted on heroin (index terms: ‘heroin dependence’ or ‘diacetylmorphine’) and marijuana (index terms: ‘marijuana abuse’, ‘marijuana smoking’, or ‘cannabis’). Those index terms were used for heroin and marijuana because the unitary terms ‘marijuana’ and ‘heroin’, unlike ‘cocaine’, are not available as search terms in MEDLINE. These searches, however, provide an equivalent subset of articles across drugs and permit a direct comparison of total citations. We cross-referenced those heroin and marijuana terms with the treatment category using the same index terms cross-referenced with cocaine. A subset of the cocaine citations (i.e., citations on reviews, cardiac effects, and perinatal
effects) were subjected to a content analysis by reviewing the title (and abstract if necessary) of each article (Budney et al., 1990). All of those citations (n = 708) were verified indicating that the citations were categorized accurately. A number of citations appeared in more than one category, and the articles varied in quality within and across categories. Results
Cocaine citations The MEDLINE search revealed a total of 5410 cocaine citations from 1966 to 1990. Total cocaine citations per year increased 4-fold between 1984 and 1990 (Fig. 1). The largest l-year increase in absolute number of total citations occurred between 1988 and 1989. A similar pattern emerged across all categories crossreferenced with cocaine, that is, treatment, cardiac effects, perinatal effects, reviews, human and non-human (Figs. 1 and 2). Increases across categories between 1984 and 1990 ranged 2.7 48.5-fold with an average increase of 12-fold. This period of rapid growth of cocaine citations lagged approximately 5-7 years behind the rapid increase in prevalence of cocaine use (Fig. 3). One noteworthy pattern was that of citations concerning humans vs. non-humans (Fig. 2). The number of cocaine citations concerning nonhumans was always greater than those with humans until 1985 when that pattern reversed and a growing discrepancy between the two has been evident since that time. The search of 1990 treatment citations revealed that only 11 of the 96 (11.4%) were research studies. Cocaine, heroin and marijuana In addition to cocaine citations, Fig. 1 also shows total citations and treatment citations for heroin and marijuana between 1966 and 1990. Citations increased dramatically for each drug during certain 7 -g-year periods (cocaine: 1984 - 90; heroin: 1968 - 75; marijuana 1966 75). To compare the rate of increase during those time periods, regression analyses were
145
TREATMENT
TOTAL COCAINE 7Wr
g
HEROIN
7w
600
600
F
Gf k
500
3
400
3
300
3w
2W
2w
loo
loo
$ 2
0
86
70
74
76
62
66
0
90
66
70
74
76
62
66
90
MARIJUANA
7M)-
700 r
1
6W
-
600
500
-
500
400-
400 I
300
-
300
200
-
200 1
loo
-
100 t
Ol 66
70
OS 66
90
70
74
76
62
66
YEARS Fig. 1. The number
of total citations
and treatment
citations
for cocaine,
heroin and marijuana
as a function
of year.
90
146
CARDIAC EFFECTS 120
PERINATAL EFFECTS
COCAINE
r
60
0
66
70
74
78
82
86
-
0
90
66
70
74
78
82
86
HUMAN VS. NONHUMAN
REVIEWS COCAINE
7
r
HUMAN
66
70
74
78
90
82
86
90
70
74
70
82
86
90
YEARS Fig. 2. The number of cocaine citations in four categories as a function of year. Note the different range on the y axis for the human-non-human panel.
conducted on citations during those specific years for each drug. Equality of slopes was tested using t-tests and Bonferroni adjustments to control for type I error rates due to multiple comparison tests. No differences between drugs in the slopes for total citations emerged, indicating that the rate of increase was comparable across them. The slope for heroin treatment citations (mean increase = 47.3 articles/year) was greater than the slopes for cocaine treatment citations (mean increase = 13.5 articles/year) (P < 0.05) and marijuana treatment citations (mean increase = 3.7 artitles/year) (P < 0.05). The slope for cocaine treatment citations was greater than the slope for marijuana citations (P < 0.05).
Discussion The MEDLlNE search on cocaine clearly documents that the scientific/clinical literature on this topic is growing, particularly over the past ‘7 years. The extant literature spans a wide range of areas addressing many basic science, health-care, and treatment issues related to coCaine use. The escalation of cocaine use and cocaine-related adverse consequences beginning in the late 1970s has been documented by various sources (e.g., Cocaine client admissions (NIDA, 1987); Drug Abuse Warning Network (NIDA, 199Oc); NIDA Household Surveys (NIDA, 1988,199Oa)). Given that publication of research results is expected to lag a number of
147
8-
COCAINE PREVALENCE
RATE
CITATIONS
n
Y4
I
I
I
I
I
I
I
76
78
80
82
84
86
88
n
90”
YEARS Fig. 3. The prevalence of cocaine use and the number of total cocaine citations as a function of year. The prevalence estimates were taken from NIDA (1991), and represent estimates of the percentage of persons age 18 - 25 in the general population who reported cocaine use during the 30 days prior to the survey.
years behind the recognition of a problem (i.e., funding must be allocated, funding proposals submitted and evaluated, research conducted, articles submitted and reviewed for publication), the present results suggest that the increase in cocaine articles temporally followed the cocaine epidemic in a relatively timely fashion. Furthermore, a comparison of the number of cocaine citations during this time period with citations concerning heroin and marijuana during the same time period (Fig. 1) indicates that the increase in cocaine articles was not merely a function of a general increase in drug abuse research. Cocaine citations increased dramatically, while heroin and marijuana citations increased only slightly over this time period. This data suggests that a substantial proportion of the increased funding available for drug abuse research since 1985 (NIDA, 1990b) was allocated to cocaine research projects and that the increase in cocaine citations was a function of that funding. Indeed, from 1986 to 1991, NIDA increased extramural funding for cocaine
research more than 11-fold (3.4 -39.5 million dollars), reflecting a change from cocaine research accounting for 6% of the NIDA’s research budget in 1986 to 17% in 1990 (NIDA, 1990b; NIDA 1991, pers. commun.). Therefore, the increase in scientific attention to cocaine could be interpreted as the scientific community responding to increased cocaine use by influencing federal funding agencies, or conversely, the scientific community being influenced by funding agencies. The initiation of increased funding for cocaine research in 1985 could be considered a lack of responsivity by funding agencies given that peak cocaine prevalence rates occurred in 1979. NIDA’s research budget, however, was relatively small until 1985 when funding for drug abuse research in general began to increase substantially (NIDA, 1990b). Thus, when funding became available, it was expediently allocated for cocaine research, and a rapid escalation of scientific publications followed. Comparisons of the increases observed in
148
cocaine citations during the past 7 years with the increases observed in heroin and marijuana citations in the late 1960s and early-mid 1970s indicate the response to the current cocaine epidemic is consistent with the historic response to other drug epidemics in the United States. The rate of increase in total citations did not differ among drugs during those comparison years. Some differences in rate and absolute number of treatment citations across drugs emerged. Heroin treatment citations appeared at a greater rate and number than cocaine or marijuana treatment citations; this likely reflects research conducted on methadone treatment for heroin dependence. For instance, the large increase in heroin citations observed in 1975 (Fig. 1) resulted from 216 citations entered into Index Medicus from a single conference on the use of methadone in the treatment of heroin dependence. Unlike heroin dependence, an agreed upon pharmacotherapy (methadone) does not exist for cocaine or marijuana dependence. Also noteworthy, the rate of increase and absolute number of marijuana treatment citations was lower than cocaine or heroin, suggesting that scientific attention to a drug is influenced by the severity of consequences associated with abusing the drug. Moreover, total and treatment citations for marijuana peaked in 1976 prior to the peak use years of 1977 to 1979 (NIDA, 199Oa). In contrast, cocaine citations peaked following peak prevalence years (accurate data on peak prevalence of heroin use was unavailable). These findings suggest that scientific attention to a drug is influenced by factors other than prevalence alone. The rapid growth periods for heroin and marijuana citations lasted approximately 8 and 10 years, respectively, after which the number of citations for both drugs plateaued, declined, and then stabilized at that lower level (Fig. 1). This pattern suggests that a similar trend may occur with cocaine citations, and that the plateau period may occur during the next few years. A number of limitations of this computer search exist. First, MEDLlNE does not cover all journals devoted to drug abuse and certainly not all articles on this topic. Therefore, the number
of citations and rates of growth reported in this review should be considered conservative estimates. Second, MEDLINE adds journals to its search list periodically. Increases in citations across years can be influenced by those additions. The comparison of cocaine citations to heroin and marijuana citations during the same time periods, however, illustrates that the increase in cocaine citations was not simply a byproduct of the inclusion of new journals on drug abuse. Third, although specific areas were searched, (e.g., treatment), this search did not provide information concerning what types of articles exist within each area. This could be misleading. For example, although treatment articles appear plentiful, the search of treatment-research citations conducted in the present study and a careful review of the cocaine treatment literature (Budney and Higgins, in press) indicates that only a few controlled treatment studies have been reported. The reader is referred to Johanson and Fischman (1989) for a comprehensive review and evaluation of specific areas of cocaine research. In summary, it is apparent that cocaine and its attendant problems have received an increasing amount of attention in the scientific/clinical literature over the past two decades, with the most dramatic escalation occurring over the past 7 years. Although there is firm evidence that the scientific/clinical community has responded to the current cocaine epidemic, a great deal more needs to be done in many cocaine-related problem areas. For example, research on the development of treatments for cocaine dependence is sorely needed. Those needs not withstanding, this increase in attention to cocaine is similar to what occurred during prior epidemics with other abused drugs. It is important that the work that has already been done is not overlooked and that this knowledge base be used to guide future research and clinical interventions. Acknowledgements Supported by the National Institute on Drug Abuse grant R18DA06113 awarded to the second author (Dr. Higgins) and National Insti-
149
tute on Drug Abuse training grant T32DA07242. We thank Catherine Goddard, Dana Medical Library, for help with the literature searches. References Budney, A.J., Delaney, D.D. and Higgins, S.T. (1990) Trends in the scientific literature on cocaine: 1966 - 1989. Paper presented at the meeting of the American Psychological Association, Boston, MA. Budney A.J. and Higgins, S.T. Psychological treatments for cocaine dependence. In: Encyclopedia of Drugs and Alcohol (Jaffe, J., ed.) in press. Committee on the Judiciary, United States Senate (1990) Hard-core cocaine addicts: Measuring and fighting the epidemic. (Publication No. 552 - 070 - 08156 - 9) U.S. Government Printing Office, Washington, DC. Congressional General Accounting Office (1990) Drug abuse: Research on treatment may not address current needs (HRD-90-114). U.S. General Accounting Office, Washington DC. Gawin, F.H. and KIeber, H. (1987) Issues in cocaine abuse treatment research. In Cocaine: Clinical and Biobehavioral Aspects (Fisher, S., Raskin, A. and Uhlenhuth, E.H., eds.), pp. 174- 192. Oxford University Press, New York. Higgins, S.T. (1990) Trends in the scientific literature on cocaine. Am. J. Med. 89, p. 544. Johanson, C.E. and Fischman, M.W. (1989) The pharmacology of cocaine related to its abuse. Pharmacol. Rev. 41, 3-52. Lerner, W.D. (1989) Cocaine abuse and acquired im-
munodeficiency syndrome: A tale of two epidemics. Am. J. Med. 87, 661-663. National Institute on Drug Abuse (1991) Statistics from the National Household Survey on Drug Abuse. In: NIDA Notes, Vol. 6 (National Institute on Drug Abuse, Ed.), pp. 31. (DHHS Publications No. ADM 90-1488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1990a) National household survey on drug abuse: Main findings 1988 (DHHS Publications No. ADM 90-1682), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (199Ob) NIDA’s response to the GAO report. In: NIDA Notes, V.5 (National Institute on Drug Abuse, Ed.), pp. 3-4. (DHHS Publications No. ADM 90 - 1488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (199Oc) Data from the Drug Abuse Warning Network (DAWN) Semiannual report, trend data through January-June 1989. (DHHS Publications No. ADM 90 - 1664), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1989) Household survey. In: NIDA Notes, V.4 (National Institute on Drug Abuse, Ed.), pp. 42-43. (DHHS Publications No. ADM 891488), U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1987) Cocaine client admissions 1976-1985. (DHHS Publications No. ADM 87 - 1528) U.S. Government Printing Office, Washington, DC. National Institute on Drug Abuse (1988) National household survey on drug abuse: Main findings 1985 (DHHS Publications No. ADM 88 - 1586) U.S. Government Printing Office, Washington, DC.
