In Forces of Habit: Drugs and the Making of the Modern World (Cambridge, Mass., 2001), David Courtwright argued that a number of highly popular intoxicants (caffeine, tobacco, alcohol, opium, coca/cocaine, and cannabis) in combination with an emerging and gradually accelerating global trade triggered a “psychoactive revolution” in the early modern era. “Psychoactive revolution” may well be the most influential single phrase ever put to paper in the historiography of drugs, elegantly summing up how six intoxicants had become so important to the modern world, and why states eventually declared “war” on half of them. Forces of Habit was also unusual for being a creditable drug history, footnotes and all, written for a popular audience by a historian who already had a pedigree for serious, fine-grained research on drugs. Although Courtwright was not the first drug scholar to recognize the significance of the early modern era (Schivelbusch preceded him), he certainly broadened the horizons of drug historians working in the much more familiar terrain of the nineteenth and twentieth centuries.1

Andreas, a historically minded political scientist who, like Courtwright, has a long resume of excellent and highly influential scholarly work, is clearly aiming toward a more popular audience. Much like Forces of Habit, or his own Smuggler Nation: How Illicit Trade Made America (New York, 2014), Andreas clearly seeks to split the difference between popular appeal and serious scholarship. History buffs will surely devour this book. Breen’s study, however, is more scholarly and rigorous, drilling down deeply into Courtwright’s notion of “psychoactive revolution.” Andreas relies almost completely on secondary sources, many of them popular histories of the six drugs central to his story, but Breen delves into materials from eleven different archives in five countries (Brazil, Portugal, Italy, England, and the United States).

Breen maintains that our present approach to drugs was born in the early modern era, a product of the global drug trade, which he calls, “an emergent property, born of a ferment of different beliefs, practices, and conflicts, following a course that was neither planned nor expected” (3). This concoction resulted in the bifurcation of drug markets into licit and illicit branches during what Breen calls the “Age of Intoxication” (he fears that a reference to “ages” might now be out of scholarly fashion, though Courtwright, who just published The Age of Addiction: How Bad Habits Became Big Business [Cambridge, Mass., 2019)] might disagree). The label is a bit misleading because Breen actually emphasizes that both psychoactive and purely medicinal drugs were important to the story. Nonetheless, he suggests that drugs had “impacts on global health, material culture, and intellectual life that were arguably even more transformative than the unevenly distributed intellectual currents of the Enlightenment” (3).

Breen offers much that is new. His focus on the British and Portuguese Empires makes for a novel but well-chosen pairing. Notwithstanding that most of the literature identifies the roots of drug prohibition in the nineteenth and twentieth centuries, Breen argues that “the assumptions underlying drug criminalization include concerns about bodily and mental purity and the trope of intoxication as an enemy of civilization.…[T]hese associations arose out of early modern conceptions of racial difference, fears of non-Christian spirituality, and the commercial imperatives of merchants, slavers, and medical professionals…. Drugs became illegal not because of the arbitrary decisions of government leaders in the nineteenth and twentieth centuries but because of deep-seated epistemological, commercial, and social structures that emerged during an earlier age of globalization on the plantation, on the slave ship, and on the surgeon’s table” (7).

To make this argument, Breen splits the story into two parts. The first focuses on his view of the Portuguese Empire as pioneering both the search for new drugs and global commodification. The second part highlights how the British eventually “cannibalized” these networks and how, “by the eighteenth century a new, more global understanding of intoxication emerged, one guided by both empiricism and orientalism. The division between drugs and pharmaceuticals sprouted in this racialized soil of Enlightenment-era debates about intoxication, science, and empire” (11). Though not the first to locate the roots of modern drug prohibitions in the early modern era, Breen’s argument along these lines is the most comprehensive and nuanced to date.

Andreas’ subject matter—the relationship between drugs and warfare—is narrower than Breen’s, but it covers a longer chronology (all recorded history, in fact) across many regions, though mostly Europe, the United States, China, and Japan. Like Forces of Habit, Andreas’ book focuses on alcohol, caffeine, opium, cocaine, and tobacco. Instead of including cannabis, however, he studies amphetamine, a relative latecomer to the drug scene (1927), but probably the drug with the most direct relationship to actual warfare. Andreas emphasizes that there were five ways that these drugs were connected to combat—“war while on drugs (drug consumption by combatants and civilians during wartime), war through drugs (the use of drugs to finance war or to weaken the enemy), war for drugs (the use of war to secure drug markets), war against drugs (the use of military means to suppress drugs or to attack or discredit military rivals in the name of drug suppression), and drugs after war (different drugs as winners or losers in the aftermath of war)” (7).

Despite its ostensibly narrow focus, Andreas’ survey of the relationship between war and drugs has an obvious breadth. Since both drugs and conflict are everywhere in history, the potential connections are boundless. This ubiquity makes for entertaining but, from an academic perspective, sometimes frustrating reading. Unlike his Smuggler Nation, which depicts the United States as a country built on smuggling, this book lacks a provocative overarching thesis. His musings in the conclusion of Killer High, however, are thought-provoking. To wit: “The term ‘narco-state’ is typically used today to describe places such as Afghanistan that are deeply enmeshed in the illicit drug trade. Yet viewed from a longer historical perspective, all the major powers can actually be labeled ‘narco-states’ in the sense that they have, at various times, in various ways, and to varying degrees, relied on drugs and drug revenue to carry out their state-making and war-making objectives” (254). Nonetheless, much of the book covers territory that will be familiar to drug scholars. Courtwright and others have already shown how dependent governments can become on taxing drugs, especially during wartime. Moreover, at this point, drug scholars are well versed in the war against cocaine and in soldiers’ propensity for coffee and cigarettes. Hence, Andreas’ book might have more appeal for a popular rather than a scholarly audience.

Andreas’ book is also suspect in its quoting of dubious contemporary sources, with the effect of vague or conflicting assertions. In the coffee discussion, for example, one source claims that by the end of World War I, the U.S. government had to provide 750,000 pounds of coffee per day to the army. The number is jaw-dropping. How many U.S. personnel were involved in World War I? The answer of 3 million, which emerges a few sentences later (from another source), establishes an individual’s average consumption of coffee as a quarter pound per day. Could it be accurate? The next quotation, which suggests 2 million American soldiers instead, yields more than one-third a pound per person per day. The internet, however, estimates the total number of U.S. personnel involved in the war as closer to 5 million (the first quotation mentioned only the “army”). A few sentences below, Andreas informs us that, during World War II, which he calls “an even more caffeinated conflict,” the U.S. military provided as much 250,000 pounds of coffee to its personnel per day. A quick internet search finds an estimated 12 million U.S. personnel in World War II, which amounts to about one-third an ounce of coffee per person per day, which would make World War II significantly less, not more, caffeinated than World War I (120-121). Which version is correct?

Other, more subtle flaws perpetuate outdated notions. For example, scholarship has strongly challenged the notion that China was overrun by opium addiction in the nineteenth century. Current research, as well as many sources from the period in question, indicates that the vast majority of opium users had only a moderate intake of the drug, but the lobbying and propaganda of reformers, both Western missionaries and Chinese nationalists, effectively overwhelmed the facts.2 Andreas conveys the traditional story of the Chinese being “hooked” on opium, its fighting capacity diminished by the drug and so forth.

These criticisms aside, the scope of Andreas’ book ensures that every reader will learn something new. Breen’s book might not be read as widely, but it will surely be widely cited in the various fields to which it speaks (drug history, the history of medicine, early modern globalization, and the Portuguese and British Empires).



Wolfgang Schivelbusch, Tastes of Paradise: A Social History of Spices, Stimulants, and Intoxicants (New York, 1992).


Frank Dikötter, Lars Laamann, and Zhou Zun, Narcotic Culture: A History of Drugs in China (Chicago, 2004). Rollo K. Newman, “Opium Smoking in Late Imperial China: A Reconsideration,” Modern Asian Studies, XXIX (1995), 765–794.