The delusion of possession in chronically psychotic patients.

Sixty-one chronically psychotic outpatients were grouped according to the presence or absence of a history of delusional possession. Compared with patients without a history of delusional possession (N = 36), possessed patients (N = 25) had significantly more self-reported childhood sexual abuse, higher dissociation scores, more cannabis abuse, more experiences of thought control, and more voices heard inside their heads. These findings support the hypothesis that in some psychotic patients, possession beliefs may reflect childhood trauma and dissociation.