Is the out-of-body experience some kind of mental illness?
Part 19 of a comprehensive Out-of-body Experience FAQ by Jouni Smed covering out-of-body experiences, astral projection, dreams and lucid dreams.
If the OBE is to be seen as involving psychological processes, rather than paranormal ones, we need to look at what those processes could be.
Let us begin with a psychiatric approach and ask whether the OBE, or anything like it, is found in any mental illness.
Noyes and Kletti likened near-death experiences to the phenomenon of depersonalization. Related to depersonalization is derealization, in which the surroundings and environment begin to seem unreal and the sufferer seems to be cut off from reality. Depersonalization is the more common of the two, and involves feelings that the person's own body is foreign or does not belong.
He may complain that he does not feel emotions even though he appears to express them, and he may suffer anxiety, distortions of time and place, and changes in his body image, and the subject may seem to observe things from a few feet ahead of his body. His conscious 'I- ness' is said to be outside his body. The patients characterize their imagery as pale and colorless, and some complain that they have altogether lost the power of imagination.
This description does not sound like that of someone who has had an OBE or a NDE. There are distortions of the environment and alterations in imagery in OBE and NDE experiences, but it seems that imagery typically becomes more bright and vivid, colorful and detailed, rather than pale and colorless. There are changes in the emotions -- but rather than a perishing of love and hate, many OBEers report deep love and joy and positive emotions. The phenomena of derealization and depersonalization do not in the least help us to understand. Any small similarities are outweighed by overwhelming differences.
One syndrome specifically involving doubles is the unusual 'Capgras syndrome.' A person suffering from this illusion may believe that a friend or relative has been replaced by an exact double. Since this double is like the real person in every discernible way, nothing that the 'real person' says or does will convince the patient otherwise. In this way the patient can avoid the guilt he feels at any malicious or negative feelings towards a loved one. From even this very brief description it is obvious that this illusion bears no resemblance to the OBE.
More relevant may be the kinds of double seen in autoscopy, literally 'seeing oneself.' Although the OBE is rarely distinguished from autoscopy in the psychiatric literature, other distinctions are made instead. The main distinction is that OBE involves feeling of being outside the body while autoscopy usually consist of seeing a double. Some people see the whole of their body as a double; some see only parts, perhaps only the face. There is an internal form in which the subject can see his internal organs; and a cenesthetic form in which he does not see, but only feels the presence of his double. There is even a negative form in which the subject cannot see himself even when he tries to look into a mirror.
An entirely different way of looking at autoscopy is through the physical problems with which it is sometimes associated. One of these is migraine, the most obvious symptom of which is the debilitating headache. During, before or after the pain some migraine suffers apparently experience autoscopy. In any case, a number of examples of people who have suffered both migraine and a simultaneous experience of either autoscopy or an OBE, does not prove any particular kind of connection between the two.