Historical Overview

In this book we argue that psychomotor disturbance (PMD) is both a key defining characteristic of melancholic depression and a reflection of its underlying pathophysiology. As noted by Rush and Weissenburger (1994), the terms “endogenous” and “melancholic” have had differing meanings, including particular patterns of clinical features. In their overview of nine “diagnostic operationalizations” of the melancholic concept, psychomotor retardation was the only feature to be included in all nine systems, while psychomotor agitation was included in six. Nevertheless, psychomotor disturbance is principally viewed as either (a) merely one of several features weighted to such a diagnosis; or (b) more related to depression severity than to depression sub-typing and, as such, to be secondary to the primary mood disturbance. We will argue that PMD's utility as a specific defining feature of melancholia is dependent on its measurement (requiring some precision in defining its underlying domains and appropriate descriptors; and using behavioural ratings rather than relying on symptom self-report data), and that such measurement difficulties have resulted in lack of appreciation of its possible “necessary and sufficient” status as a melancholic sub-typing feature.