Alice in Wonderland syndrome (AIWS), or micropsia, is a disorienting neurological condition which affects human visual perception.
An illustration by John Tenniel of Alice rapidly growing.
Subjects perceive humans, parts of humans, animals, and inanimate objects as substantially smaller than in reality. Generally, the object perceived appears far away or extremely close at the same time. For example, a family pet, such as a dog, may appear the size of a mouse, or a normal car may look shrunk to scale. This leads to another name for the condition, Lilliput sight or Lilliputian hallucinations, named after the small people in Jonathan Swift's Gulliver's Travels. The condition is in terms of perception only; the mechanics of the eye are not affected, only the brain's interpretation of information passed from the eyes.
The syndrome is associated with, and perhaps in part caused by, the classical migraine headache. Occasionally, Alice in Wonderland syndrome is named as one of the first symptoms of mononucleosis. Micropsia can also be caused by complex partial epilepsy, and the actions of various psychoactive drugs (notably dextromethorphan).
Small children, usually between the ages of five and ten, form a large proportion of those afflicted by spontaneous temporary micropsia. Micropsia tends to occur during darkness, when the brain lacks visual size references.
Micropsia not only affects visual perception, but also one's hearing, sense of touch, and sometimes one's own body image; the syndrome continues even when the eyes are closed. Peripheral symptoms include anxiety, apraxia, and agnosia. Micropsia is also commonly related to patients suffering schizophrenia.
The disorder is named after Lewis Carroll's Alice's Adventures in Wonderland, where the title character experiences many situations similar to those of micropsia and macropsia. Because Lewis Carroll recorded at least one episode of classical migraine, scholars have speculated that he may have experienced this syndrome himself.
