Reddit reviews Hallucinations

Nearly everyone hallucinates at some point in their life. It's quite common and most cases are not associated with drug intake or mental illness. And a variety of physical or mental stimuli and practices can reliably induce hallucinatory states in most individuals. Some kinds of hallucinations in very young children, for example, can be a normal part of development.

However, just because drugs or mental illness are not the cause of most hallucinations it does not mean that they're medically irrelevant. Spontaneously hallucinating for no discernible reason is not unheard of, but rare compared to cases where a cause can be determined.

For a scientific overview of the matter I suggest Oliver Sacks book "Hallucinations." He's a great writer and famed for his work in the treatment of a variety of neurological disorders (I think Robin Williams played his character in "Awakenings.")

http://www.amazon.com/Hallucinations-Oliver-Sacks-ebook/dp/B0082XLY6G/ref=sr_1_1?s=digital-text&ie=UTF8&qid=1396330412&sr=1-1&keywords=hallucinations

Hallucinations I've been wanting to read this book for a while, it seems interesting!

This isn't a hallucination, it's a misperception. Hallucination is when you see something that isn't actually there, but misperception is when you see what is there incorrectly.

EDIT: Read the introduction of Oliver Sacks's Hallucinations. He can explain the difference between the two better than I can.

For those who don't want to go through the effort of reading the whole thing, here's a relevant excerpt:

>Hallucinations may overlap with misperceptions or illusions. If, looking at someone's face, I see only half a face, this is a misperception. The distinction becomes less clear with more complex situations. If I look at someone standing in front of me and see not a single figure but five identical figures, is this "polyopia" a misperception or a halluc9ination? If I see someone cross the room from left to right, then see them crossing the room in precisely the same way again and again, is this sort of repetition a perceptual aberration, a hallucination, or both? We tend to speak of such things as misperceptions or illusions if there is something there to begin with--a human figure, for example--whereas hallucinations are conjured out of thin air. But many of my patients experience outright hallucinations, illusions, and complex misperceptions, and sometimes the line between these is difficult to draw.