Datura

Datura is a powerful deliriant plant whose tropane alkaloids act as competitive antagonists of the muscarinic acetylcholine (ACh) receptors. Its pharmacological class is distinct from those of psychedelics, dissociatives and entactogens: it produces a delirium in the clinical sense, not an integrable psychedelic state.

Neurochemical action

The tropane alkaloids of datura (atropine, scopolamine, hyoscyamine) are competitive antagonists of the muscarinic M1 to M5 receptors of acetylcholine (ACh) in the brain and nervous system. By occupying these muscarinic receptors, they block cholinergic transmission. The result is a loss of ACh-dependent functions: muscarinic antagonism acts both centrally and peripherally. The main mechanisms involved are arousal and attention, memory (learning and the formation of new memories), marked anterograde amnesia, and a deep cognitive and perceptual disruption.

Bayesian predictive loop

The plate places datura within a predictive framework. Muscarinic blockade disorganises attention, working memory and sensory filtering. The upper levels of the model are no longer corrected by ascending sensory evidence (bottom-up). The result is a heavily disturbed prediction error: the internal model becomes incoherent, fragmented and amnesic. Internal reality substitutes itself for shared reality, inducing a state of deep confusion and amnesia.

Mechanisms of delirium (cholinergic dysregulation)

The plate breaks delirium down into several stages. Transmission of the internal model is disrupted, disorganising attention, the formation of the memory trace and sensory filtering. The internal model becomes incoherent, fragmented and self-sufficient, no longer constrained by reality. Indistinguishable hallucinations then appear: the internal constructions take on the status of the real, indistinguishable from ordinary perception. The clinical spatio-temporal delirium leads to a loss of orientation, false beliefs and convincing delusional scenarios. Finally comes amnesia of the event: the memory of the episode is fragmentary or entirely absent.

Phenomenology

The functional consequences described include a chaotic, vivid delirium indistinguishable from reality; major cognitive disorganisation (loss of spatio-temporal orientation, of logic); marked anterograde amnesia, an inability to form new memories or to retain the experience; unpredictable time, dilated or frozen; perceptions that are present but perceived as malevolent, hostile or threatening; incoherent or impossible communication; significant physical effects (dry mouth, mydriasis, tachycardia, urinary retention, hyperthermia). Datura differs from classic psychedelics: its delirium is convincing, not recognised as such, without introspection, and the boundary of reality is often abolished or uncontrollable.

Harm reduction

The plate strongly stresses the danger. Duration is highly variable: onset 20 to 60 minutes, peak 1 to 3 hours, total duration 6 to 24 hours, with after-effects (fatigue, confusion, dry mouth) and a slow reintegration. Tolerance and the therapeutic margin are narrow: the active dose and the lethal dose are close, and alkaloid content varies greatly from one plant to another, making dosing unpredictable. The precautions stressed: potentially dangerous physical effects, risk of accident, injury and coma, indispensable supervision by another person, inadvisable in cases of psychiatric, cardiac or glaucoma conditions, uncertain plant identity. Datura remains a shamanic, deliriant, toxic plant whose use belongs to strictly framed ritual practices and requires medical supervision.

Sources

• Pharmacological literature on tropane alkaloids (atropine, scopolamine, hyoscyamine) and antagonism of the muscarinic acetylcholine receptors.
• Work on the cholinergic system, attention and memory.
• The predictive coding and Bayesian inference framework in neuroscience (Friston; Carhart-Harris and Friston, on the predictive brain and altered states).
• Clinical toxicology of solanaceae (Datura, Brugmansia) and anticholinergic syndromes.