Glossary of drug classifications

Understanding the basics

Classifications of Drugs

Here’s your guide to the words scientists use to classify drugs based on how they affect the body and mind.

Why Substance Terminology Matters
Knowing the right words to describe substances—both scientific and everyday terms—can help reduce confusion, stigma, and misinformation.

Whether you're talking with friends, navigating online research, or having open conversations with family, clear terminology fosters understanding and promotes safer choices.

This glossary is designed as a practical tool to help you decode the language around substances, so you can approach these topics with confidence and clarity. Use it to bridge gaps between technical explanations and real-world conversations, ensuring you’re informed and able to communicate effectively in any setting.

In everyday conversations, people often use simpler terms—like “uppers” and “downers,” for example. These words aren’t scientific, but they make sense in casual discussions and offer a clear way to talk about a drug’s general effects. To dig deeper and understand a drug, and to truly use research as a part of an informed consent process, we can use the internet to find specific terms.

This is not to become a walking substance dictionary. It’s for our own inner understanding. I think we can all do with some conversations and reading to better understand and take responsibility for choosing which substances we put in our bodies—and which ones we will not.

Understanding both the technical and informal language around substances is valuable. It promotes personal safety, health literacy, and better decision-making.

It’s also important to note that some drugs don’t fit neatly into just one category. For example, cannabis can act as a stimulant, depressant, or psychedelic depending on factors like dose, the user’s physiology, or the setting. Similarly, terms like psychedelic, hallucinogenic, and entheogenic may be used interchangeably when describing substances like psilocybin mushrooms, though they carry slightly different connotations.

This glossary introduces common terms used to classify substances often encountered in recreational settings. It’s not exhaustive, nor does it outline the risks or potential harms associated with these substances. Rather, it’s a starting point for building a better understanding of substance terminology.

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Amphetamines: A class of stimulant drugs that increase activity in the central nervous system. Users feel more energy, focus, and alertness. These substances are used medically to treat certain conditions, though they are also commonly misused for their stimulating effects.

• Examples: prescription stimulants (Adderall, Ritalin), methamphetamine

Anesthetics: Substances that temporarily reduce or eliminate sensation, often to allow medical procedures to be performed without pain. While primarily used medically, some anesthetics are also used recreationally because they lead to feelings of euphoria, dissociation, or relaxation.

Examples: ketamine, nitrous oxide, PCP (Phencyclidine)

Cannabinoids: While it doesn't fit neatly into one category, cannabis and its components (e.g., THC, CBD) have diverse effects, including relaxation, mild euphoria, and altered sensory perception. Cannabis could also be considered a depressant, stimulant, or mild hallucinogen, depending on the dose and the individual.

• Example: cannabis

Depressants: Also called “downers.” Substances that slow down the central nervous system, leading to relaxation, lowered inhibitions, and drowsiness. While the name might sound like these substances cause emotional depression, they don’t; they actually "depress" or reduce brain and body activity.

• Examples: alcohol, GHB, heroin, benzodiazepines (Xanax, Valium), and prescription painkillers (oxycodone)

Dissociatives: Substances that distort sensory perception and create feelings of detachment from the environment or one's body and mind. These effects can feel dreamlike or out-of-body.

• Examples: ketamine, nitrous oxide, salvia divinorum.

Entheogens: Substances used in spiritual or ceremonial contexts to induce mystical or transcendent experiences. The intention is often to connect with a higher power, nature, or one’s inner self. Some entheogens are being studied for their therapeutic potential in treating PTSD, anxiety, and depression.

• Examples: ayahuasca, psilocybin mushrooms, peyote (mescaline), DMT (Dimethyltryptamine)

Empathogens: Substances that enhance feelings of emotional connection, empathy, and openness toward others. Empathogens are known for their ability to foster deep interpersonal bonding, reduce social anxiety, and encourage introspection.

• MDMA (3,4-Methylenedioxymethamphetamine), MDA, (3,4-Methylenedioxyamphetamine)

Hallucinogens: Substances that alter perception, thought, and mood, often leading to visual, auditory, or sensory hallucinations. Some—but not all— psychedelics are hallucinogenic, so the term is sometimes used interchangeably.

• Examples: LSD, psilocybin, DMT, ayahuasca

Opioids or Opiates: Substances that bind to opioid receptors in the brain and body to relieve pain and produce feelings of euphoria. Opioids are also depressants.

• Examples: heroin, morphine, fentanyl, and prescription painkillers (oxycodone, hydrocodone)

Psychedelics: Substances that affect brain receptors to alter perception, mood, and cognition. They often produce vivid sensory experiences, a loss of a sense of - a separate self sometimes called “ego dissolution,” and profound introspection. Psychedelics are sometimes considered a subset of hallucinogens.

• Examples: LSD, psilocybin, DMT, mescaline, and ayahuasca

Sedatives: Substances that calm the central nervous system, reducing anxiety and promoting relaxation or sleep. These can overlap with depressants, depending on the context.

• Examples: benzodiazepines (Valium, Ativan), barbiturates, and certain prescription sleep aids (Ambien)

Stimulants: Also called “uppers.” Substances that increase brain and body activity, often leading to heightened alertness, energy, and feelings of euphoria.

• Examples: caffeine, nicotine, cocaine, methamphetamine, and prescription stimulants (Adderall, Ritalin)