Meaning of psilocybine: An older spelling that persists in drug indexes and research listings, kept alive by cataloging rather than by any difference in chemistry.

Definition of psilocybine

Psilocybine is an alternative spelling of psilocybin, the hallucinogenic compound made by mushrooms of the genus Psilocybe and a few related genera. Both spellings name the same molecule, and psilocybin is the form used in most current writing. The body converts it into psilocin, which acts on serotonin receptors in the brain to produce altered perception and mood.

Why do two spellings exist?

Both forms entered English from the chemical literature, where the ending -ine marks a nitrogen containing plant or fungal compound, as in morphine and nicotine. Psilocybin became the standard form in English, while psilocybine survives in older texts, in drug indexes and in translated material, since French and several other languages keep the extra letter. The difference is one of spelling and nothing more. It matters for searching, though, because a database filed under one spelling will not return records stored under the other, so both are worth checking when references on the molecule are being gathered.

What is it being studied for?

Research has concentrated on conditions where existing treatment often fails. Trials have examined depression that has not responded to standard antidepressants, anxiety and existential distress in people living with advanced illness, and dependence on alcohol and tobacco. The design is unlike ordinary drug testing. A small number of supervised sessions is wrapped in preparatory and follow-up psychological work, so the drug and the therapy around it cannot easily be separated when results are interpreted. It remains investigational for every one of these uses, meaning it is not an approved treatment, and the evidence rests on relatively small studies with participants who often guess correctly which group they are in.

How does a research setting differ from other use?

FeatureIn a clinical trialOutside one
DoseWeighed, standardized and recordedUnknown, since mushroom potency varies widely
ScreeningPersonal and family psychiatric history reviewed firstNone
SupervisionTrained monitors present throughout the sessionAbsent or informal
Legal positionConducted under specific regulatory authorizationA controlled substance offense in most places

The gap between those two columns is the main reason findings from supervised trials say very little about unsupervised use. Almost every element that the trial controls, from the dose to the presence of someone trained to manage a frightening reaction, is missing outside it.

Also known as

psilocybin

Used in a sentence

Psilocybine was administered under controlled conditions as part of a clinical research protocol studying its effect on treatment-resistant depression.

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Good to know

Psilocybine itself is largely inactive until the body converts it into psilocin, the compound that actually produces its perceptual and mood-altering effects, a distinction sometimes lost when the two names are used interchangeably.

Word origin

Where “psilocybine” comes from

The name derives from Greek psilos, meaning bare or smooth, and kybe, meaning head, referring to the smooth cap characteristic of the Psilocybe mushroom genus in which the compound was first identified.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.