If we look for scientific sources for information about OBEs we find practically none at all. Scientists have rarely paid any attention to these phenomena. This kind of circular reasoning in support of one's comfortable belief system is not unique to scientists by any means, but it has resulted in very little scientific research on ESP or OBEs. First, OBEs are a universal human experience, not in the sense that they happen to large numbers of people, but in that they have happened all through reported history, and there are marked similarities in the experience among people who are otherwise extremely different in terms of cultural background. One can find reports of OBEs by housewives in Kansas which closely resemble accounts of OBEs from ancient Egyptian or Oriental sources.
Illnesses sometimes bring it about, especially illnesses which are almost fatal.
Great emotional stress sometimes brings it about. In many cases, it simply happens during sleep without our having any idea of what might have caused it. In very rare instances it seems to have been brought about by a deliberate attempt. Third, the experience of a OBE is usually one of the most profound experiences of a person's life, and radically alters his beliefs. The person feels that he has directly experienced being alive and conscious without his physical body, and therefore knows that he possesses some kind of soul that will survive bodily death.