Clinical delusions have been grouped in any number of ways. Many pre-twentieth-century inventories focus on what they are delusions about (their “content”). Lycanthropy was the notion that one had turned into a wolf, for example; other delusions involved ideas about jealousy, grandeur, guilt or hypochondriacal matters, and often, the self. More recent taxonomies sort according to structural features, i.e. aspects of the status of delusional content (as untrue, implausible or impossible), and to the tenacity with which delusions are held in the face of countervailing evidence. Clinical delusions have been shown to correspond to these traits only incompletely, however. Some delusions are untrue or implausible – but some are not, and many do not lend themselves to such assessment. Moreover delusions are adhered to with varying degrees of conviction, depending on their content, and also on the stage of their development. (The process of recovery from delusions, for example, seems to include a “double-awareness” phase, when patients are able to question the validity of their delusional beliefs although they have not abandoned them entirely.)1
The inventory provided in this chapter is not systematic or comprehensive. Its aim is merely to show dimensions other than the structural ones just noted by which delusions vary.