Lewis Carroll's children's novel "Alice's Adventures in Wonderland" turns 150 this year, but a less-celebrated discovery also has an anniversary: the discovery of "Alice in Wonderland syndrome" (AIWS).

British psychiatrist John Todd named the syndrome in 1955. Micropsia (when things appear smaller than they are) often occurs along with a migraine. However, new information shows that it isn't just a migraine - or a magic mushroom - that causes AIWS, according to a new case study.

The acid-test-esque nature of the fluidly odd tale of Alice has had many speculating on which opiate Carroll took while writing the book. "Mr. A," as the test subject is called in the case study, presented with a history of marijuana use, alcohol and tobacco use and "recreational use" of LSD.

"During LSD intoxication, he reported the presence of four frequent visual illusions, namely, macropsia (seeing thing too big), micropsia, pelopsia (seeing things too close) and teleopsia (seeing things too far)," the study authors wrote. "These visual distortions were reported when looking at still or moving objects, human and non-human beings. When interviewed Mr. A unhesitatingly and precisely attributed psychedelic experience solely to LSD intake. Two days after completely stopping all substance use due to a longer than expected hallucinogenic experience associated with slight anxiety, he surprisingly noticed the returning of some visual imagery previously experienced. For example, books were seen slightly closer, chairs were seen slightly further away, his hands were seen larger than they actually were, his dog's head was seen smaller."

Study authors noted, "To the best of our knowledge, this is the first reported case of AIWS which persist[s] after LSD interruption." The reason for 26-year-old Mr. A's visual distortions is still unclear, but after a year, the symptoms went away.

AIWS could also be part of migraine auras. Sheena Aurora, a neurologist and migraine specialist at the Stanford University School of Medicine, said that an aura is a rare phenomenon - occurring in only 20 percent of migraine patients. The subset that suffers with AIWS is an even smaller percentage, Aurora told Live Science.

Aurora said she believes AIWS is caused by a hypersensitivity in the occipital lobe (visual region), but can spread to the neighboring parietal lobes. "The parietal area is what discerns sizes and shapes," Aurora said.

There is no historical basis to believe that Carroll was a dropper of wormwood, a smoker of opiates or a frequent visitor to any drug den. His journals do mention a rough time with migraines, so perhaps his aura-inducing migraines created his Wonderland adventures.