Internal hallucinations

Internal hallucinations are visual experiences that arise within the mind's eye rather than in perceived external space — seen with eyes closed, in the dark, or wherever external visual input is reduced.

As a drug effect they are acute and dose-dependent, fading as the substance wears off, which distinguishes them from the spontaneous imagery of persistent psychotic conditions. They range from faint geometric forms or fleeting dreamlike scenes to fully immersive, narrative visions of complex and vivid character.

They are commonly reported at the upper end of the dose range across several substance classes. Most often induced at high doses under psychedelics such as LSD, psilocybin mushrooms, and DMT, and under dissociatives such as ketamine, dextromethorphan, and 3-MeO-PCP; they also appear under opioids such as heroin and methadone, and at high doses of depressants such as methaqualone and gabapentin.

Internal hallucinations are felt as a shift inward: external surroundings recede and the closed-eye field becomes a screen for imagery that arrives unbidden.

At lower intensities this may be geometric — lattices, tunnels, slowly rotating forms — but it can resolve into recognizable scenes, figures, and narrative sequences that carry the subjective weight of reality. A quality of involuntary watching is characteristic; the content is not willed into being.

At high doses, particularly under dissociatives, the internal space can feel architecturally vast, and imagery may become indistinguishable from dream.

Internal hallucinations arise through different pathways depending on the drug class:

• Psychedelics — act at 5-HT2A receptors, destabilizing sensory gating and amplifying spontaneous activity in visual cortex; this generates structured imagery in the absence of external input.
• Dissociatives — block NMDA receptors, interrupting normal sensory flow and allowing internal generative processes to dominate perception.
• Opioids — act at mu-opioid receptors; the mechanism is less well characterized but appears linked to their sedating and dream-promoting properties.
• Depressants — at high doses, suppress sensory processing through GABA-A potentiation, allowing internal imagery to surface.

How much each pathway contributes in a given case is not fully understood.

Who experiences it, and how intensely, varies widely. It is reliably dose-dependent — low to moderate doses rarely produce it, and the onset threshold shifts with both the substance class and individual sensitivity.

Set and setting play a meaningful role, especially under psychedelics and dissociatives: a dark, quiet environment with eyes closed strongly favors onset, while active engagement with the external world suppresses it. Prior experience with imagery-producing substances tends to enrich the content. Some individuals report vivid internal hallucinations at moderate doses; others reach high doses without them.