Classic Psychedelics: What the Term Covers

What the term covers

"Classic psychedelics" is a pharmacology term, not a cultural one. [2] A 2016 pharmacology review reports a consensus that these drugs are agonists or partial agonists at brain serotonin 2A receptors. [3]

An "agonist" is a substance that switches a receptor on. A receptor is a docking point on a brain cell. The page Serotonin Receptors in Plain Language explains what this does and does not tell us.

The four named examples

Each example has a different origin, which is one reason the word "classic" should not be read as "natural" or "traditional".

DMT and ayahuasca are not the same thing: see DMT vs Ayahuasca.

What they are reported to do

NIDA reports that people using these drugs describe vivid visions or sensations, a changed sense of self, and feelings ranging from intense happiness and connection to fear, anxiety and confusion. [2] NIDA says studies suggest the most prominent effects stem from activity in the prefrontal cortex and that these drugs temporarily disrupt communication between brain regions, including the default mode network. [2] How much that matters for any health benefit is a separate question, covered in Proposed Mechanisms vs Proven Clinical Outcomes.

What "classic" does not mean

• Not "safe". NIDA says effects vary widely and can include fear, anxiety and dangerous behavior, and that there is some evidence these drugs might trigger a schizophrenia-like illness in people with predisposing factors. [2]
• Not "the same drug". The four examples differ in origin, chemistry and the research behind them. See Why Different Substances Cannot Be Treated as Equivalent.

Evidence labels on this page

This page makes classification statements, not treatment claims. Where it touches approval it uses the label approved medicine (a regulator has approved a product for a stated use) only for what the regulator has actually approved. Treatment evidence for specific conditions is on the pages for major depressive disorder and PTSD. The full list of labels is in how we label evidence.

Education only

This guide describes categories. It gives no amounts, no sourcing or preparation information and no advice to use or to treat yourself.