Akademik
octa - Oppe
octave illusion
ocular spectra
oculomotor macropsia
oculomotor micropsia
old age and hallucinations
olfactism
olfactory aura
olfactory flashback
olfactory hallucination
olfactory illusion
olfactory phantasma
olfactory reference syndrome
Oliver Sacks's Syndrome
ololiuqui-induced hallucination
OLP
oneirism
oneirogagic image
oneiroi
oneiroid hallucination
onomatomania
OOBE
ophthalmopathic hallucination
opiates and hallucinations
opioid-induced hallucination