- Email: [email protected]
Behavioral and economic perspectives in drug abuse research
Drug and Alcohol Dependence 90S (2007) S1–S3
Editorial
Behavioral and economic perspectives in drug abuse research
Keyword: Economics
We are pleased to introduce this supplemental issue of Drug and Alcohol Dependence entitled Behavioral and Economic Perspectives in Drug Abuse Research, which resulted from a workshop on this topic developed by the U.S. National Institute on Drug Abuse. Three divisions within the Institute1 developed this meeting to facilitate an interdisciplinary dialogue regarding the conceptual and methodological issues involved in analyzing drug markets. We believed the field would be enriched by a sharing of perspectives, challenges and solutions among behavioral, sociological, and economic researchers. We found that broad inclusion of many disciplines, including cognitive and consumer psychology, neuroscience and epidemiology, provided invaluable insight into the dynamics of street-level drug markets. The meeting also served the goals of the National Institutes of Health Roadmap Initiative which mandates a speedy translation of research results to practice. As such, this supplement seeks to highlight the importance of understanding and promoting integrated approaches to research, elucidating the interactions between individuals and environments that contribute to the continuum of problems related to drug abuse, and developing scientific knowledge with clear application to practice and public policy. Research increasingly suggests the importance of studying drug abuse2 from the perspective of the behavior of individuals within the context of environments. Drug markets are a critical component of this context, one that has not received due research attention. Previous work has focused on the community, contextual, and individual level environmental factors that influence drug abuse and its consequences such as educational 1 Sponsoring NIDA divisions: the Division of Epidemiology, Services, and Prevention Research, the Division of Basic Neuroscience and Behavioral Research, and the Division of Clinical Neuroscience, Development, and Behavioral Research. 2 The term “drug abuse” as used in this introduction refers broadly to several different but related concepts including drug abuse and dependence as defined by diagnostic criteria, as well as drug involvement, hazardous drug use, drug seeking behavior, drug use as an adverse health behavior, and the like. While it is recognized that these concepts may not be interchangeable, the term drug abuse is used for the purposes of fluency.
0376-8716/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.drugalcdep.2007.05.002
and occupational problems, crime and violence and co-morbid conditions. Less attention has been given to social environmental phenomena such as drug trafficking and distribution, gang activities, family disruption and neighborhood structure and dysfunction. A focus on drug using behavior within the context of drug distribution activities could also generate new knowledge and hypotheses regarding drug types and quantities used, the adulterants, diluents, and contaminants present in retail drugs, and patterns of use of drug classes, including polydrug use. For example, a better understanding of the composition of retail street drugs could provide insights regarding distribution networks and drug price purity. Although data are available on the frequency of drug use, a deficit exists regarding estimates of drug price and purity and other drug consumption data. Research in this area could thus add to our empirical knowledge of streetlevel drug use and/or our understanding of market and other mechanisms that shape and are shaped by these patterns of use. In addition, a comprehensive understanding of patterns of drug acquisition and use must account for changes over time as new drugs, new modes of administration, and new population groups become prominent. Principles of behavior derived from economics, sociology and other macro-environmental disciplines have great potential for expanding our knowledge of these phenomena, providing a more comprehensive understanding of the influences that impact drug abuse. To better understand drug markets, researchers must consider the entire range of factors that affect the decisions of sellers and drug users. Economic explanations may help elucidate decisions made by users to enter and stay in treatment. Although traditional econometric analyses of existing databases have contributed to our knowledge and continue to be supported, there is a deficit of new data. New and more adequate models are needed to better assess the use, desistance and substitution of drugs. Small-scale epidemiologic studies could better characterize price, demand, and consequence at the level of a city or other small geographic areas. Ethnographic studies could describe price and availability effects on the behavior of different types of drug consumers, evaluating, for example, whether and how the elasticity of demand varies with the severity of drug
S2
Editorial / Drug and Alcohol Dependence 90S (2007) S1–S3
use and logic of dependence. Epidemiological, ethnographic or survey data could be used to guide laboratory-based simulation research using behavioral economic approaches to elucidate the relationship between the price and availability of alternative commodities on individual demand which, in turn, could be associated with neurophysiologic changes. The perspectives of behavioral economics, consumer psychology, drug availability market factors, the role of norms and institutional rules, and other related areas, may identify important but understudied pieces of the drug markets puzzle. Cognitive psychology and neuroscience provide insights into the decision-making processes of both drug users and drug sellers. Research areas include the origins, development, structure, and operation of drug markets, the informational aspects of the drug trade, as well as the complex cognitive process of delay discounting among drug abusers. People, on average, discount gains more than losses, but drugdependent individuals demonstrate varying effect magnitudes in discounting future drug-consumption. Bickel et al. (2004) and Johnson et al. (2004) found that heroin addicts discounted future money more deeply than heroin and that the difference is greater than fifty percent, whereas needle sharers discount money and needles by the same amount and cigarette smokers discount cigarettes more than money. Even research examining macro-level environmental constructs can be informed by findings from cognitive and neuroscience approaches. Social cognitive neuroscience and neuro-economics are emerging disciplines that seek to explain social behavior and decision making in terms of underlying information processing and neurobiological mechanisms. These disciplines recognize that drug abuse is a complex phenomenon that is affected by variables operating at many levels of functioning from the neurobiological (e.g., variation in receptor function, neural circuit interactions) to the social (e.g., peer influences on decision making, drug markets). Whereas neurobiological variables have been well represented in the scientific literature of drug abuse, social context variables have only recently begun to appear in well-controlled studies. Yet, variations in social context are important in the decisions that lead to the initiation, maintenance, and relapse to drug abuse and addiction. Social context is both a risk factor for drug abuse and addiction and a protective factor against it. Effective prevention and treatment of drug abuse and addiction rely on recruiting and harnessing a host of social variables. For example, group- and family-based therapies for substance abuse disorders capitalize on social factors in reducing drug use and preventing relapse. Understanding how brain function, decision making and social behavior are reciprocally interrelated under these and related conditions will lead to a detailed and integrated understanding of brain function in a social context, and, perhaps, a more complete understanding of how the combined influence of these factors contributes to drug abuse and the treatment of drug addiction. Collaborative research that links epidemiologists, sociologists, economists, psychologists, neuroscientists and other drug researchers from different disciplines will enhance our perspectives. Specifically, economic analyses of factors involved in street-level drug markets such as price and purity, consumption, and cross-elasticities can be paired with research about
drug availability and accessibility, patterns of use, and trajectories of use within certain populations. In addition, the use of nested case control studies within larger epidemiologic studies could enhance laboratory-based behavioral economic analysis of defined populations, including environmental influences on behavioral economic measures such as delay discounting functions, impulsivity and risk taking. For instance, the effects of impulsivity on juvenile drug abuse and dependence in certain neighborhoods or the relationship of occupational, educational, and other opportunity structures to drug use and desistance within defined segments of the population. The significance of this supplemental issue is that it brings together multiple areas of inquiry including behavioral science, economics, and neuroscience, provides a critical review of existing research, identifies gaps and discusses priority areas for future research. In particular, the authors in this issue link macroand micro-environmental factors such as drug markets and their contextual and market dynamics such as availability, price, and initiation to drug use, as well as articulating conceptual and methodological issues of importance when linking economics and psychology in addiction research. For example, Galea et al. (2007) link neighborhood disadvantage to drug use, finding a clear association of neighborhood-level distribution of education attainment with alcohol and marijuana use, signifying the importance of understanding the role that broader environmental concepts play in drug-using behavior. Johnson and Golub (2007) explore the link between the structure of drug markets and individual user behavior. Harrison et al. (2007) examine and compare drug markets involving youth in school, youth in the criminal justice system, and youth who have dropped out of school. Sifaneck et al. (2007) compare the markets for commercial marijuana with the market for designer marijuana and the extent to which these differences may be based upon different THC potencies. Brownstein and Taylor (2007) compare and contrast the disruption of methamphetamine markets in 10 cities and explore how markets with different patterns of stability exhibit different patterns of drug using and treatment participation. Caulkins (2007) provides an important conceptual overview and review of the arguments for understanding how price affects use and how supply disruptions affect price and purity, and why an understanding of how these are measured is critical to drug market research. Chandra (2007) demonstrates the utility of historical consumption data in understanding the interaction of drug using behavior based on varying levels of intensity of consumption with price elasticities. Bickel et al. (2007) explore the link between temporal discounting and the development and maintenance of drug addiction and how this approach can inform novel approaches to designing effective prevention and treatment programs. Rachlin (2007) compares and contrasts the behavioral economic conceptualization of rationality versus the addict’s notion of rationality and how an understanding of the differences and similarities in meaning can inform interventions. Monterosso and Ainslie (2007) provide a conceptual discussion of how an understanding of hyperbolic discounting and choice bundling among drug users can inform interventions. The editors believe that this broad range of topics reflects the importance of a multidisciplinary
Editorial / Drug and Alcohol Dependence 90S (2007) S1–S3
approach to understanding behavior dynamics associated with person–environment interaction in the link between drug using behavior and drug distribution and manipulation. The proposal for this supplemental issue of the journal was developed by us, as the Guest Editors. After approval by the journal editor and publisher, we invited the authors to prepare the papers. Each of the papers went through a rigorous blinded peer review process which we managed in consultation with the journal editor, Dr. Robert Balster. After we approved author revisions, the papers were released to the journal editorial office where they were again assessed for scientific merit by the editor. Financial support for the publication of this supplemental issue was provided by the National Institute on Drug Abuse. Finally, we wish to acknowledge the thought and effort devoted to planning the workshop, to presenting at the workshop, and to writing the papers for this supplemental issue. We also wish to thank the reviewers for their incisive comments on the manuscripts. It is our expectation that this volume will serve as a resource for the field and will encourage and stimulate collaborations that make use of innovative, cutting-edge methodologies and models that collect or assemble original datasets, adopt multi-method approaches, and/or incorporate additional measures in ongoing studies. References Bickel, W.K., Giordano, L.A., Badger, G.J., 2004. Risk-sensitive foraging theory elucidates risky choices made by heroin addicts. Addiction 99, 855–8561. Bickel, W.K., Miller, M.L., Yi, R., Kowal, B.P., Lindquist, D.M., Pitcock, J.A., 2007. Behavioral and neuroeconomics of drug addiction: competing neural systems and temporal discounting processes. Drug Alcohol Depend. 90, S85–S91. Brownstein, H.H., Taylor, B.G., 2007. Measuring the stability of illicit drug markets: why does it matter? Drug Alcohol Depend. 90, S52–S60. Caulkins, J.P., 2007. Price and purity analysis for illicit drug: data and conceptual issues. Drug Alcohol Depend. 90, S61–S68. Chandra, S., 2007. Economic manifestations of opiate addiction: evidence from historical data from colonial Indonesia. Drug Alcohol Depend. 90, S69–S84. Galea, S., Ahern, J., Tracy, M., Rudenstine, S., Vlahov, D., 2007. Education inequality and use of cigarettes, alcohol, and marijuana. Drug Alcohol Depend. 90, S4–S15.
S3
Harrison, L.D., Erickson, P.G., Korf, D.J., Brochu, S., Benschop, A., 2007. How much for a dime bag? An exploration of youth drug markets. Drug Alcohol Depend. 90, S27–S39. Johnson, B.D., Golub, A., 2007. The potential for accurately measuring behavioral and economic dimensions of consumption, prices, and markets for illegal drugs. Drug Alcohol Depend. 90, S16–S26. Johnson, M.W., Bickel, W.K., Kirshenbaum, A.P., 2004. Substitutes for tobacco smoking: a behavioral economic analysis of nicotine gum, denicotinized cigarettes, and nicotine-containing cigarettes. Drug Alcohol Depend. 74, 253–264. Monterosso, J., Ainslie, G., 2007. The behavioral economics of will in recovery from addiction. Drug Alcohol Depend. 90, S100–S111. Rachlin, H., 2007. In what sense are addicts irrational? Drug Alcohol Depend. 90, S92–S99. Sifaneck, S.J., Ream, G.L., Johnson, B.D., Dunlap, E., 2007. Retail marijuana purchases in designer and commercial markets in New York City: sales units, weights, and prices per gram. Drug Alcohol Depend. 90, S40–S51.
Yonette F. Thomas a,∗ Paul Schnur b a Division of Epidemiology, Services, and Prevention Research, National Institute on Drug Abuse, Department of Health and Human Services, Bethesda, MD 20852, USA b Division of Basic Neuroscience and Behavioral Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20852, USA a
Martin Y. Iguchi a,b RAND, Drug Policy Research Center, Santa Monica, CA 90407, USA b UCLA School of Public Health, Los Angeles, CA 90005, USA
∗ Corresponding
at: Epidemiology Research Branch, Division of Epidemiology, Services, and Prevention Research, National Institute on Drug Abuse, 6001 Executive Blvd., Room 5185, MSC 9589, Bethesda, MD 20892-9589; (for FedEx) Rockville, MD 20852, USA. Tel.: +1 301 402 1910; fax: +1 301 443 2636. E-mail address: [email protected] (Y.F. Thomas) 11 April 2007
Editorial
Behavioral and economic perspectives in drug abuse research
Keyword: Economics
We are pleased to introduce this supplemental issue of Drug and Alcohol Dependence entitled Behavioral and Economic Perspectives in Drug Abuse Research, which resulted from a workshop on this topic developed by the U.S. National Institute on Drug Abuse. Three divisions within the Institute1 developed this meeting to facilitate an interdisciplinary dialogue regarding the conceptual and methodological issues involved in analyzing drug markets. We believed the field would be enriched by a sharing of perspectives, challenges and solutions among behavioral, sociological, and economic researchers. We found that broad inclusion of many disciplines, including cognitive and consumer psychology, neuroscience and epidemiology, provided invaluable insight into the dynamics of street-level drug markets. The meeting also served the goals of the National Institutes of Health Roadmap Initiative which mandates a speedy translation of research results to practice. As such, this supplement seeks to highlight the importance of understanding and promoting integrated approaches to research, elucidating the interactions between individuals and environments that contribute to the continuum of problems related to drug abuse, and developing scientific knowledge with clear application to practice and public policy. Research increasingly suggests the importance of studying drug abuse2 from the perspective of the behavior of individuals within the context of environments. Drug markets are a critical component of this context, one that has not received due research attention. Previous work has focused on the community, contextual, and individual level environmental factors that influence drug abuse and its consequences such as educational 1 Sponsoring NIDA divisions: the Division of Epidemiology, Services, and Prevention Research, the Division of Basic Neuroscience and Behavioral Research, and the Division of Clinical Neuroscience, Development, and Behavioral Research. 2 The term “drug abuse” as used in this introduction refers broadly to several different but related concepts including drug abuse and dependence as defined by diagnostic criteria, as well as drug involvement, hazardous drug use, drug seeking behavior, drug use as an adverse health behavior, and the like. While it is recognized that these concepts may not be interchangeable, the term drug abuse is used for the purposes of fluency.
0376-8716/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.drugalcdep.2007.05.002
and occupational problems, crime and violence and co-morbid conditions. Less attention has been given to social environmental phenomena such as drug trafficking and distribution, gang activities, family disruption and neighborhood structure and dysfunction. A focus on drug using behavior within the context of drug distribution activities could also generate new knowledge and hypotheses regarding drug types and quantities used, the adulterants, diluents, and contaminants present in retail drugs, and patterns of use of drug classes, including polydrug use. For example, a better understanding of the composition of retail street drugs could provide insights regarding distribution networks and drug price purity. Although data are available on the frequency of drug use, a deficit exists regarding estimates of drug price and purity and other drug consumption data. Research in this area could thus add to our empirical knowledge of streetlevel drug use and/or our understanding of market and other mechanisms that shape and are shaped by these patterns of use. In addition, a comprehensive understanding of patterns of drug acquisition and use must account for changes over time as new drugs, new modes of administration, and new population groups become prominent. Principles of behavior derived from economics, sociology and other macro-environmental disciplines have great potential for expanding our knowledge of these phenomena, providing a more comprehensive understanding of the influences that impact drug abuse. To better understand drug markets, researchers must consider the entire range of factors that affect the decisions of sellers and drug users. Economic explanations may help elucidate decisions made by users to enter and stay in treatment. Although traditional econometric analyses of existing databases have contributed to our knowledge and continue to be supported, there is a deficit of new data. New and more adequate models are needed to better assess the use, desistance and substitution of drugs. Small-scale epidemiologic studies could better characterize price, demand, and consequence at the level of a city or other small geographic areas. Ethnographic studies could describe price and availability effects on the behavior of different types of drug consumers, evaluating, for example, whether and how the elasticity of demand varies with the severity of drug
S2
Editorial / Drug and Alcohol Dependence 90S (2007) S1–S3
use and logic of dependence. Epidemiological, ethnographic or survey data could be used to guide laboratory-based simulation research using behavioral economic approaches to elucidate the relationship between the price and availability of alternative commodities on individual demand which, in turn, could be associated with neurophysiologic changes. The perspectives of behavioral economics, consumer psychology, drug availability market factors, the role of norms and institutional rules, and other related areas, may identify important but understudied pieces of the drug markets puzzle. Cognitive psychology and neuroscience provide insights into the decision-making processes of both drug users and drug sellers. Research areas include the origins, development, structure, and operation of drug markets, the informational aspects of the drug trade, as well as the complex cognitive process of delay discounting among drug abusers. People, on average, discount gains more than losses, but drugdependent individuals demonstrate varying effect magnitudes in discounting future drug-consumption. Bickel et al. (2004) and Johnson et al. (2004) found that heroin addicts discounted future money more deeply than heroin and that the difference is greater than fifty percent, whereas needle sharers discount money and needles by the same amount and cigarette smokers discount cigarettes more than money. Even research examining macro-level environmental constructs can be informed by findings from cognitive and neuroscience approaches. Social cognitive neuroscience and neuro-economics are emerging disciplines that seek to explain social behavior and decision making in terms of underlying information processing and neurobiological mechanisms. These disciplines recognize that drug abuse is a complex phenomenon that is affected by variables operating at many levels of functioning from the neurobiological (e.g., variation in receptor function, neural circuit interactions) to the social (e.g., peer influences on decision making, drug markets). Whereas neurobiological variables have been well represented in the scientific literature of drug abuse, social context variables have only recently begun to appear in well-controlled studies. Yet, variations in social context are important in the decisions that lead to the initiation, maintenance, and relapse to drug abuse and addiction. Social context is both a risk factor for drug abuse and addiction and a protective factor against it. Effective prevention and treatment of drug abuse and addiction rely on recruiting and harnessing a host of social variables. For example, group- and family-based therapies for substance abuse disorders capitalize on social factors in reducing drug use and preventing relapse. Understanding how brain function, decision making and social behavior are reciprocally interrelated under these and related conditions will lead to a detailed and integrated understanding of brain function in a social context, and, perhaps, a more complete understanding of how the combined influence of these factors contributes to drug abuse and the treatment of drug addiction. Collaborative research that links epidemiologists, sociologists, economists, psychologists, neuroscientists and other drug researchers from different disciplines will enhance our perspectives. Specifically, economic analyses of factors involved in street-level drug markets such as price and purity, consumption, and cross-elasticities can be paired with research about
drug availability and accessibility, patterns of use, and trajectories of use within certain populations. In addition, the use of nested case control studies within larger epidemiologic studies could enhance laboratory-based behavioral economic analysis of defined populations, including environmental influences on behavioral economic measures such as delay discounting functions, impulsivity and risk taking. For instance, the effects of impulsivity on juvenile drug abuse and dependence in certain neighborhoods or the relationship of occupational, educational, and other opportunity structures to drug use and desistance within defined segments of the population. The significance of this supplemental issue is that it brings together multiple areas of inquiry including behavioral science, economics, and neuroscience, provides a critical review of existing research, identifies gaps and discusses priority areas for future research. In particular, the authors in this issue link macroand micro-environmental factors such as drug markets and their contextual and market dynamics such as availability, price, and initiation to drug use, as well as articulating conceptual and methodological issues of importance when linking economics and psychology in addiction research. For example, Galea et al. (2007) link neighborhood disadvantage to drug use, finding a clear association of neighborhood-level distribution of education attainment with alcohol and marijuana use, signifying the importance of understanding the role that broader environmental concepts play in drug-using behavior. Johnson and Golub (2007) explore the link between the structure of drug markets and individual user behavior. Harrison et al. (2007) examine and compare drug markets involving youth in school, youth in the criminal justice system, and youth who have dropped out of school. Sifaneck et al. (2007) compare the markets for commercial marijuana with the market for designer marijuana and the extent to which these differences may be based upon different THC potencies. Brownstein and Taylor (2007) compare and contrast the disruption of methamphetamine markets in 10 cities and explore how markets with different patterns of stability exhibit different patterns of drug using and treatment participation. Caulkins (2007) provides an important conceptual overview and review of the arguments for understanding how price affects use and how supply disruptions affect price and purity, and why an understanding of how these are measured is critical to drug market research. Chandra (2007) demonstrates the utility of historical consumption data in understanding the interaction of drug using behavior based on varying levels of intensity of consumption with price elasticities. Bickel et al. (2007) explore the link between temporal discounting and the development and maintenance of drug addiction and how this approach can inform novel approaches to designing effective prevention and treatment programs. Rachlin (2007) compares and contrasts the behavioral economic conceptualization of rationality versus the addict’s notion of rationality and how an understanding of the differences and similarities in meaning can inform interventions. Monterosso and Ainslie (2007) provide a conceptual discussion of how an understanding of hyperbolic discounting and choice bundling among drug users can inform interventions. The editors believe that this broad range of topics reflects the importance of a multidisciplinary
Editorial / Drug and Alcohol Dependence 90S (2007) S1–S3
approach to understanding behavior dynamics associated with person–environment interaction in the link between drug using behavior and drug distribution and manipulation. The proposal for this supplemental issue of the journal was developed by us, as the Guest Editors. After approval by the journal editor and publisher, we invited the authors to prepare the papers. Each of the papers went through a rigorous blinded peer review process which we managed in consultation with the journal editor, Dr. Robert Balster. After we approved author revisions, the papers were released to the journal editorial office where they were again assessed for scientific merit by the editor. Financial support for the publication of this supplemental issue was provided by the National Institute on Drug Abuse. Finally, we wish to acknowledge the thought and effort devoted to planning the workshop, to presenting at the workshop, and to writing the papers for this supplemental issue. We also wish to thank the reviewers for their incisive comments on the manuscripts. It is our expectation that this volume will serve as a resource for the field and will encourage and stimulate collaborations that make use of innovative, cutting-edge methodologies and models that collect or assemble original datasets, adopt multi-method approaches, and/or incorporate additional measures in ongoing studies. References Bickel, W.K., Giordano, L.A., Badger, G.J., 2004. Risk-sensitive foraging theory elucidates risky choices made by heroin addicts. Addiction 99, 855–8561. Bickel, W.K., Miller, M.L., Yi, R., Kowal, B.P., Lindquist, D.M., Pitcock, J.A., 2007. Behavioral and neuroeconomics of drug addiction: competing neural systems and temporal discounting processes. Drug Alcohol Depend. 90, S85–S91. Brownstein, H.H., Taylor, B.G., 2007. Measuring the stability of illicit drug markets: why does it matter? Drug Alcohol Depend. 90, S52–S60. Caulkins, J.P., 2007. Price and purity analysis for illicit drug: data and conceptual issues. Drug Alcohol Depend. 90, S61–S68. Chandra, S., 2007. Economic manifestations of opiate addiction: evidence from historical data from colonial Indonesia. Drug Alcohol Depend. 90, S69–S84. Galea, S., Ahern, J., Tracy, M., Rudenstine, S., Vlahov, D., 2007. Education inequality and use of cigarettes, alcohol, and marijuana. Drug Alcohol Depend. 90, S4–S15.
S3
Harrison, L.D., Erickson, P.G., Korf, D.J., Brochu, S., Benschop, A., 2007. How much for a dime bag? An exploration of youth drug markets. Drug Alcohol Depend. 90, S27–S39. Johnson, B.D., Golub, A., 2007. The potential for accurately measuring behavioral and economic dimensions of consumption, prices, and markets for illegal drugs. Drug Alcohol Depend. 90, S16–S26. Johnson, M.W., Bickel, W.K., Kirshenbaum, A.P., 2004. Substitutes for tobacco smoking: a behavioral economic analysis of nicotine gum, denicotinized cigarettes, and nicotine-containing cigarettes. Drug Alcohol Depend. 74, 253–264. Monterosso, J., Ainslie, G., 2007. The behavioral economics of will in recovery from addiction. Drug Alcohol Depend. 90, S100–S111. Rachlin, H., 2007. In what sense are addicts irrational? Drug Alcohol Depend. 90, S92–S99. Sifaneck, S.J., Ream, G.L., Johnson, B.D., Dunlap, E., 2007. Retail marijuana purchases in designer and commercial markets in New York City: sales units, weights, and prices per gram. Drug Alcohol Depend. 90, S40–S51.
Yonette F. Thomas a,∗ Paul Schnur b a Division of Epidemiology, Services, and Prevention Research, National Institute on Drug Abuse, Department of Health and Human Services, Bethesda, MD 20852, USA b Division of Basic Neuroscience and Behavioral Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20852, USA a
Martin Y. Iguchi a,b RAND, Drug Policy Research Center, Santa Monica, CA 90407, USA b UCLA School of Public Health, Los Angeles, CA 90005, USA
∗ Corresponding
at: Epidemiology Research Branch, Division of Epidemiology, Services, and Prevention Research, National Institute on Drug Abuse, 6001 Executive Blvd., Room 5185, MSC 9589, Bethesda, MD 20892-9589; (for FedEx) Rockville, MD 20852, USA. Tel.: +1 301 402 1910; fax: +1 301 443 2636. E-mail address: [email protected] (Y.F. Thomas) 11 April 2007