ABSTRACT
The diagnosis and social definition of demonic illness is a discourse which engages the expert knowledge of exorcists and the lay understandings of exorcists' clients and others. This chapter discusses how demonic illness is generally conceptualized and some of the factors which may account for the efficacy of exorcism in the treatment of demonic illness. In their diagnosis exorcists also examine the social context of the patient and the patient's household for indications of malign demonic attention. The diagnosis of demonic illness stresses malign supernatural intervention in the causation of illness and assembles and codifies many of the ideas and attitudes by which Sinhalese interpret, understand and order their daily lives. Major exorcisms act upon demonic illness in the fullness of its manifestation in a patient and upon illness as it achieves a wider significance in a social context surrounding a patient.
