Regarding the belief in Dybbuks, a Rabbi at Aish.com explains:
http://www.aish.com/atr/Dybbuk.htmlDybbukI recently received tickets to a ballet called "The Dybbuk," with music by Leonard Bernstein. It sounds like something like the "Jewish Exorcist." Please tell me what this is all about.
The Aish Rabbi Replies:A dybbuk is a case of a dead person, whose soul is sent wandering by God because the soul does not merit eternal rest. In some instances that soul may "chase" a living person and enter that person's body - this creating a situation where an alien, second soul lives through the person's body. The word "dybbuk" is derived from the Hebrew word meaning "attachment."
In the Bible (Samuel 18:10), a bad spirit is briefly described as attaching itself to King Saul. Two of the most influential rabbis in modern history - Rabbi Yosef Karo (author of the Shulchan Aruch) and the Chafetz Chaim (author of the Mishnah Berurah) - have both have told of experiences regarding dybbuks - so such stories cannot be dismissed so quickly.
The exorcism ritual involves a quorum of 10 men who gather in a circle around the possessed person. The group recites Psalm 91 three times, and the rabbi blows a shofar (ram's horn) with certain notes, in effect to shake the possessing soul loose.
Such a case was reported recently in Israel, where a woman's dead husband came back, and began "speaking" through her. A team of rabbis went in and chased the dybbuk out of the woman. The story received widespread press throughout Israel, and seems to have been 100 percent true. As a result, many people were encouraged to look deeper into the issue of spirituality, and to some degree, this had the effect of turning some Jews back to Torah.