The Drug Wheel

Categorising and classifying drugs has become more complex in the last 20 years, with an increase in new psychoactive substances.

This ever-expanding drug landscape has resulted in the development of The Drug Wheel, which classifies drugs as part of the following 7 general categories: Stimulants, Depressants, Cannabinoids, Psychedelics, Opioids, Dissociatives and Empathogens.

The Drug Wheel is also regularly updated to represent emerging chemical and legal changes to the classification of substances. 1


These include caffeine, nicotine, amphetamines, and cocaine.
Stimulant drugs speed up the messages between the brain and the body. They can make a person feel more awake, alert, confident or energetic.
Large doses of stimulants can cause over-stimulation, causing anxiety, panic, seizures, headaches, stomach cramps, aggression and paranoia. Long-term use of strong stimulants can also cause these effects.


These include alcohol, benzodiazepines (minor tranquilisers), GHB, and some inhalants.
Depressants do not necessarily make a person feel depressed. They affect the central nervous system, slowing down the messages between the brain and the body.
They can affect concentration and coordination. They slow down the person’s ability to respond to unexpected situations. In small doses they can cause a person to feel more relaxed and less inhibited. In larger doses they can cause drowsiness, vomiting, unconsciousness and death.


These include psilocybin, peyote, and LSD

Psychedelics affect numerous chemicals within the brain, leading to changes in the mechanisms that control consciousness, mood, cognition and perception, and stimulate visual centres.2,3

They can affect an individual’s capacity to recognise reality, think rationally or communicate with others.3

Psychedelics may elicit deeply personal and spiritual experiences for individuals, though can also cause periods of confusion and turmoil, activating regions responsible for panic and stress, agitation and increased heart rate.3,4


These include ketamine, PCP, nitrous oxide, and DMX.

Different dissociative substances act on different chemicals in the brain to produce visual and auditory distortion, and a sense of floating, or detachment from reality.

The effects can be highly dependent on the amount of substance ingested, and can often be unpredictable, lasting from hours to days.

At low doses they can produce numbness, confusion, disorientation, dizziness, changes to sensory perception. In higher doses they may cause hallucinations, memory loss, distress, anxiety, increases in heart rate, paranoia, panic and aggression.5


Includes substances such as MDMA, ecstasy, PMMA, Ethylone.

Empathogens are substances that increase an individual’s feeling of empathy and benevolence towards others and increase feelings of being socially accepted by and connected to others.6

They can increase friendliness and playfulness,7 but can also cause mood swings, dehydration and depression.


These include cannabis and synthetic cannabis/cannabinoids

Cannabinoids act on the Endocannabinoid system within the body. This is a chemical messaging system in the body, responsible for activating nerve cells and helping to dictate the level of neurotransmitters (dopamine) that they release, and the resulting effects of these neurotransmitters on the body.

Cannabinoid receptors are present in many parts of the brain and body, and thus the effects of cannabinoid-based drugs are wide ranging. These can vary from feeling calm and relaxed, increased appetite, anxiety, paranoia, and increased heart rate.

You can find information on different types of cannabis and their use here.


These include heroin, methadone, oxycodone, opium and codeine.

Opioids are a class of drug that are chemically related and interact with opioid receptors on cells within the brain. These receptors elicit a range of responses within the body, from feeling of pain relief, to relaxation, pleasure and contentment.8

The short-term effects of opioids include extreme relaxation, drowsiness and clumsiness, feeling of pleasure and pain relief. Some people experience nausea and vomiting. These effects will vary depending on how much of the opioid is consumed, and the mode of consumption e.g. oral or injected.8 Long term effects include dependence, constipation and damage to vital organs such as the lungs, brain and heart.

  1. Adley, M, 2018 “The Drug Wheel’, The Drug
  2. Winkelman, MJ, 2017 ‘The Mechanism of Psychedelic Visionary Experience: Hypotheses from Evolutionary Psychology’ Front Neuroscience, 2017, 11, 539.
  3. NIDA. (2015, February 1). Hallucinogens and Dissociative Drugs.
  4. Krebs TS, Johansen P-Ø (2013) Psychedelics and Mental Health: A Population Study. PLoS ONE 8(8)
  5. NIDA, 2015, ‘What are the effects of common dissociative drugs on the brain and body’ NIDA, 2015
  6. EMCDD, 2018, ‘Brief Glossary of Terms : Empathogen’ EMCDD, 2018
  7. MDMA: Empathogen or love potion? (2010, December 29). Biotech Week, 741
  8. National Institute of Drug Abuse for Teachers, 2014, ‘ Mind Over Matter: Prescription Pain Medication (Opioids)