The Guardian has a insightful piece by journalist Rik Hemsley describing his personal experiences with Alice in Wonderland syndrome, where the ‘body image’ or ‘body map’ becomes distorted, leading the affected person to feel like particular parts of the body, or the whole of it, have changed size or shape.
It doesn’t usually involve direct visual hallucinations, but can lead to the sensation that the world around you has grown to an enormous size, or that you have shrunk.
It was first described by psychiatrist John Todd in a 1955 article that you can read freely online, which I discovered when writing an previous post on the neurology of Alice in Wonderland.
It’s usually associated with epilepsy or migraine although is actually quite common, although not always in such an intense form as The Guardian article describes.
Children often experience it but grow out of it as they reach adulthood (both of which happened to me).
Link to Guardian article ‘I have Alice In Wonderland syndrome’ (via BB).
Link to full-text of Todd’s original article.