The history of mental symptoms during the nineteenth century can be explored from four complementary perspectives: descriptive psychopathology (DP), aetiological theory, pathogenesis and taxonomy. DP refers to the language of description, aetiology to underlying causes, pathogenesis to the mechanisms that disrupt brain structure and /or function which, in turn, generate symptoms, and taxonomy to the clustering rules which govern symptom grouping. DP (also called ‘psychiatric semiology’ in Continental countries) owes much to eighteenth century theory of signs; psychiatric aetiological theory and pathogenesis were moulded upon nineteenth century developments in general medicine; and taxonomy grew out of metaphors of order and classificatory principles developed during the Enlightenment. This book deals exclusively with the history of DP and enjoins historians to tackle the remainder, i.e. the history of psychiatric aetiological theory, pathogenesis and taxonomy during the nineteenth century on which, so far, near to nothing of substance has been written.

The development of DP

Inter alia, DP can be defined as a descriptive-cum-cognitive system designed to capture aspects of abnormal behaviour. This it does by applying words to segments of speech and action. To achieve its purpose, two components are needed: a lexicon and segments (symptoms or referents) which have to be ‘outlined’ or ‘constructed’. Since the latter are not obviously delimited or tagged, the naming function of DP often entails fracturing the behaviour presented by mentally ill patients. Furthermore, since the resulting ‘fragments’ are not equally informational, only some need to be kept. The rules for such a decision are based on nosological and aetiological theories of mental illness.