Why, it is fair to ask, is a member of the clergy so interested in drugs? This interest might be unremarkable if the purpose of my writing was to condemn drug users and to warn the young and impressionable away from the evil snares of any (or at least most) forms of chemical intoxication. My interest, instead, is rooted in a firm belief that drugs are deeply misunderstood. It is in this misunderstanding, both the belief in demon drugs and the hope for miraculous ones, that we have created a cultural falsehood that is perfectly tailored to maximize drug related harm and diminish possible benefits. Whether a drug is a tool for human flourishing or becomes known for its powers of destruction is not just based on physical or chemical properties, but what we believe to be true about the drug.
A drug is not so much a thing as a relationship. Fire results from a chemical reaction inside the proper atmosphere, and drugs are only drugs because of the reactions they produce in organisms. Toxic and intoxicating are not inherent molecular properties but describe interactions between a chemical and a living thing. For a drug to be a drug, it needs to cause a reaction in a creature, and these reactions aren’t consistent across organisms. The same chemical might be inert for one being, a poison for the next, and a pleasurable but risky treat for another.
Drugs are challenging to define, but a broad starting point is to understand drugs as chemicals that affect biological function. But even drinking water has characteristics we associate with drug use: the ingestion of a chemical that may provide pleasure and is deadly at a high enough dose. If a person doesn’t have access to water, it may affect their mood, behavior, and cognitive ability and cause substantial pain, all results that we would commonly associate with withdrawal from a drug.
For this reason, many definitions of a drug explicitly exclude what we ingest for the purpose of hydration and nutrition. This exclusion, however, is still fraught with difficulties. Bhang, a cannabis-infused drink in India consumed for thousands of years, is both hydrating and nutritious and will give the user a buzz. Flour made from the coca leaf contains cocaine and is rich in calcium, potassium, phosphorous, and vitamin C. It may be added to bread baked in various regions of the Andes Mountains for extra energy and stamina. Cacao, from which we make chocolate, is used in some ritual ceremonies to alter consciousness and contains theobromine, a drug.
Sugar creates feelings of pleasure and affects mood and behavior. Ceasing processed sugar consumption can cause withdrawal symptoms and, when consumed in excess, has significant negative health effects. Labeling sugar consumed as food as a drug is a controversial stance. However, the debate gets messier when considering those who have used glucose injections for performance enhancement. Today’s grocery store shelves are packed with foods with chemical additives designed in laboratories for the specific purpose of affecting our central nervous systems in ways that encourage ongoing, repeated use, even at great detriment to our health. While some argue that the categories should remain distinct, it is clear that many companies manufacturing hyperpalatable foods are doing their best to blur any functional distinction.
The food-versus-drug debate is far from new. Some scholars use the term food-drug to describe the dual purpose many substances have served throughout history. Ale and other forms of beer, for example, served as both an important alternative to unsafe water and a significant source of daily calories. Even our modern-day spice cabinets would have doubled as medicine cabinets a century ago. Cloves contain an oil that was used for toothaches and a version of that oil is still used in modern dentistry. Black pepper is a stimulant and was a target of some Prohibitionists, who wanted to curtail its use along with alcohol and morphine. Saffron is an exhilarant and antidepressant; it may speed the absorption of other drugs and has a long-standing role in traditional Islamic medicine. Nutmeg has psychedelic qualities when taken in sufficient quantities (although the effects are often quite unpleasant) and even had brief popularity among some early jazz musicians. The psychoactive nature of spices today is so ubiquitous it has led some researchers to wonder if the reason why we find their taste pleasant is the small, mostly imperceptible alterations of mood and perception they provide. While not the greatest problem facing us today, psychiatry journals publish articles on identifying and addressing the harmful use of culinary spices. For primates and some other mammals today, an estimated 15–25 percent of the total diet consists of medicinal foods or foods that also contain potentially beneficial drugs. As previously noted, the rise in use of GLP-1 drugs for weight loss and to address addictions has demonstrated that chemicals we used to believe only had to do with digestion or blood sugar regulation are associated with what we have long considered a moral issue of self-control. Research continues to explore the role of the bidirectional communication between our gut and our brain and to demonstrate how chemical signals from nonhuman cells inside our bodies can change how we think and behave.
As drugs emerged from an evolutionary perspective as poisons, the difference between a drug and a poison is blurry. The sixteenth-century physician Paracelsus is often credited as the founder of modern toxicology and with saying, “What is there that is not poison? All things are poison and nothing is without poison. Solely the dose determines that a thing is not a poison.” Warfarin sodium is a common rat poison and the most widely used human blood thinner in the world. Plants like mandrake, henbane, and datura are widely classified as poisonous today as they are highly potent and at even fairly low doses can be fatal. However, just a few centuries ago, they would have also been considered important medicines. Even something as deadly as cobra venom can be and is used as a drug for its reportedly euphoric effects at the proper dosage.
Difference in effects based on dosage or intensity of exposure is not an anomaly but a common phenomenon for organisms and even individual cells called hormesis. Low to moderate levels of stress, like what might be induced during exercise, have positive effects for humans. Keep going for too long, however, and those prolonged activities start to create short and long-term problems. Drugs, when ingested, can have two, if not three, different waves of effects. This is how the same drug, alcohol, can be stimulating for many people after a drink or two and sedative when more is consumed. Drug use doesn’t involve simple calculations of cause and effect but complex interactions between a host of factors with results described through norms and averages, not always definitive results.
Drug as a category is not a natural taxonomy or dictated by clear scientific laws. Psilocybin, for example, is by some definitions not a drug but what is called a prodrug. This means that psilocybin does not directly alter human consciousness; instead, psilocybin is reliably transformed by enzymes in our bodies into the chemical psilocyn, which does affect our consciousness. Even the understanding of drugs as chemicals or even substances has been disputed. The rogue chemist and drug researcher Alexander Shulgin took an especially expansive definition of a drug to include “something that modifies the expected state of a living thing.” For him, this included everything from radiation to ideas. The only things he didn’t think were drugs were food, sleep, and sex, and he said even then, he wasn’t sure he was right to exclude those. While this expansive definition runs the danger of leaving the word drug devoid of meaning, the idea is far from new and is an important provocation.
Drugs have been primarily thought of as highly intimate chemical technologies absorbed into our bodies in a way that is distinctive from other forms of primarily external technologies. This line is blurring. Now, other forms of technology, like our smartphones, feel and function as if they were a part of ourselves. Sudden cessation of a digital activity, like online gaming, has been shown to produce physical withdrawal symptoms. We are only beginning to understand the ways these intimate technologies change the brain and manipulate levels of neurotransmitters in ways analogous to drugs. Increasingly, various drugs are combined with other forms of biotechnology for the purpose of sustained low dose administration of a pharmacological agent. Early forms of electric shock therapy to manipulate brain responses were often barbaric and cruel, but newer forms of this kind of therapy have become increasingly sophisticated and effective. Eye movement desensitization and reprocessing is a widely used therapeutic technology, and transcranial magnetic stimulation is an emerging field with promising results for treating depression. Flicker light stimulation can be used to induce altered states of consciousness as well as sensory deprivation tanks. These are all nonpharmacological technologies with effects often associated with pharmacology. Lines drawn today are already porous and will only become more blurred in the years and decades to come.
While drug might be challenging to define, neuroscientist Judith Grisel provides a few principles concerning drugs that are helpful to keep in mind, her “three laws of psychopharmacology.” The first is that “drugs can’t do anything new, which is because they only work at all by interacting with existing brain structures. It follows that drugs can either speed up or slow down ongoing neural activity—and that’s it.” A drug is only a drug because there is a chemical sufficiently similar to something already in the body: A drug needs a place to go, something to interact with. While drugs make us feel or see things in a new way, that is only possible because our bodies are capable of something similar without the drug. We feel the specific effects of opioids because they so closely resemble endorphins and can bind to the same receptors as our endorphins. A drug like alcohol has more wide-ranging effects as it engages the main inhibitory neurotransmitter in the brain, gamma-aminobutyric acid (GABA).
Grisel’s second axiom is that “all drugs have side effects.” While our naturally occurring neurotransmitters are often highly targeted, when we ingest an external chemical, it binds everywhere it can all at once, often producing a wider spectrum of interactions. Our nervous system acts with precision; the chemicals we ingest, with a blunt force. Side effects might be mild or severe, pleasant or unpleasant. But what constitutes a side effect is also a matter of perspective. Opium was often used to treat dysentery because it has a constipating effect. When opium is used to treat pain, the same constipation is an unwanted side effect. While drugs need to be similar enough to engage existing systems, they also tend to have enough difference that the potential for negative or unintended consequences is always part of the deal.
Grisel’s third law is that “the brain adapts to all drugs that affect it by counteracting the drug’s effects.” With the mood-boosting effects of alcohol can come the crash. The more consistent and repeated the administration of a substance, the more significant the adaptations. Grisel describes how she used to wake up and begin to feel energized by the natural circadian rhythms of her body. But when she began drinking coffee, it didn’t take long for a change to occur. She writes, “Rather than feel normal before coffee and wide awake after, I now feel lethargic before I get it and only begin to approach normalcy with the second cup.” While opioids initially made me feel euphoric, after extended use, I needed a baseline level to make me feel normal, and with the absence of opioids, I felt the pains of withdrawal and depleted levels of the endorphins my body had stopped making.
A final consideration is that only a part of a drug’s effects is due to the drugs themselves. Both the mindset we approach drug use with, as well as the setting of the use, can profoundly change the experience of the drug. This phenomenon is often referred to in the shorthand of “set and setting”. While we can reliably describe the chemical effects of alcohol in most people, how they experience the effects of alcohol and what they decide to do with those feelings, varies widely. One might experience warm intimacy over a cocktail with one’s partner, a sense of joy at a wedding with a few glasses of wine, camaraderie with coworkers at a happy hour, or a sense of unity with strangers while drinking beer at a concert or sports event. The chemical reactions that allow for these experiences also increase the likelihood of embarrassing behavior, questionable judgment, unnecessary physical risks, and significant acts of anger and violence.
Our beliefs, contexts, and expectations are not just ethereal subjective aspects of our experience but can have direct chemical corollaries. Over time, a person who comes home after work each day and makes themselves a cocktail will train their body to expect a certain chemical process to begin based on specific cues and habituated expectations, just as Pavlov famously demonstrated with his salivating dogs. The body will prepare chemically for the effects of alcohol based on those cues before the alcohol has been consumed. So, if that person one day decides not to follow that routine, they are likely to not only miss the relaxing effects of that drink but experience a heightened state of anxiety as the body has prepared to balance out the anticipated effects of the alcohol.
In one case study, the setting of drug use was the difference between life and death. A couple who had been using heroin daily together at home both decided to quit the next day. However, the husband on his way to work decided to stop at his dealer’s and buy his normal dose of heroin. But instead of using it at home in a familiar context, he used it in a public bathroom and was later found dead. The difference between life and death was not the dose but the context. In clinical settings, a person who self-administers a drug will experience diminished effects as to someone who is administered the same dose but by another person when they don’t expect it. The anticipation and preparation for taking a drug triggers physiological changes that shift how the drug is experienced.
A drug is in the eye of the beholder. Griffiths Edwards notes, “Drugs are chemicals but they are potently symbols. . . . Whatever the chemical, it is likely to find itself dressed up by society with symbolic meanings, packaged as a social construct, and made into a good and cherished, or evil and hated, object.” A drug, then, is not just about the relationship between a chemical and an organism but also about the power of the symbol created by society. A significant portion of how we experience the chemical reaction is social understanding and personal experience. In fact, drugs like cannabis and nicotine are often only experienced as pleasurable after a period of social learning and physical familiarity. The initial effects might be unpleasant or disorienting, but with repeated administration and positive social reinforcement, one can learn how to both navigate and enjoy the experience quickly.
In this way, the origin stories we tell about drugs, mythic, religious, and scientific, are a part of the creation of the drugs themselves. To understand drugs, we need to look not just at biology and chemistry but at culture and religion, those things that shape what we believe to be true about ourselves and the world. This swirling interaction between what we ingest, what we think and the alteration of our consciousness is so ancient and deep that even Plato understood the very practice as a kind of pharmakon, a drug that could understood as either poison or medicine—sometimes both.
The distinctions we make have been and will continue to be blurry, as we are in a near-constant state of ingesting various chemicals that speed up or slow down existing neural processes. Our very breath involves a chemical interchange with our environment developed over time through natural selection, and how we breathe can create mild to profound alterations of consciousness, from a sense of calm to psychedelic-like effects through practices like holotropic breathing. A drug user is not a description of a discrete subcategory of humans defined by a distinctive behavior—it’s a description of what it means to be human.
Excerpted from What Drugs are For: An Exploration of Stolen Fire Copyright ©2026 by Timothy McMahan King. Used with permission of the publisher, Fortress Press. All rights reserved.
