ABSTRACT
This chapter reviews the frequency, clinical characteristics and phenomenology of passivity symptoms and the rating scales that assess them. Passivity symptoms signify a qualitative change in the thought process, characterized by a lack of normal sense of ownership for thoughts and actions, disturbed sense of boundary between the self and others, and the experience of one's will as replaced or influenced by that of some external agent. Epidemiological evidence also shows that these symptoms are "culturally robust", occurring with comparable frequency in different countries and cultures. Passivity symptoms have sometimes been assessed using general psychopathology scales, such as the Scale for the Assessment of Positive Symptoms (SAPS), but this scale is limited in that it only assesses a small subset of passivity symptoms. The research community has brought these symptoms together as a family of symptoms, the fact remains that they are poorly understood and under researched.
