I am currently rereading the late Dr. William Baldwin's fascinating and controversial book, Spirit Releasement Therapy. As a practicing dentist Dr. Baldwin's work with hypnosis and resulting experience with entity attachment prompted him to obtain a second doctorate in psychology and develop his own form of depossession - Spirit Releasement Therapy.
Entity attachment is a modern term used for what was once called possession. Spirit releasement or depossession is the process used to move the attached discarnate entity into the light and differs from traditional exorcism insofar that it seeks to provide the entity with a spiritual alternative to attachment rather than simply 'casting it out' allowing it reattach to the same client or another vulnerable person at a later date.
Practitioners believe that spirit attachment plays a role in a high percentage of mental instabilities, addictions and other negative behaviors. In this video Dr. Baldwin interviews a client freely discussing her own attachment.