The personal disturbance scale (DSSI/sAD): Development, use and structure

Abstract

This is the second in a series of three articles reviewing and reassessing Foulds' theoretical conceptions of personality disturbance and personal illness and the scales that were developed to assess them. In this report we review the theoretical development of DSSI/sAD (Delusions-Symptoms-States Inventory/states of Anxiety and Depression, otherwise known as the Personal Disturbance Scale) and describe how it fits into Foulds' theories. The intended use of sAD is discussed and the many past and current applications of the sAD are reviewed. Studies of the sAD's psychometric structure are rare and we present a new analysis, including confirmatory factor analysis of sAD in 480 psychiatric patients. The sAD items' factorial structure fits largely with its authors' conceptions. However, the sAD items cover an anxiety-depression continuum, rather than distinct states of anxiety and depression. The sAD's item structure may be interpreted within three current conceptualisations of mood: (1) that of general psychological distress; (2) that of clinical states of anxiety and depression; and (3) that of ‘normal’ mood dimensions of hedonic tone and tense arousal. It is argued that the sAD might provide a theoretical bridge for the integration of these ideas, and help to bring about a unified model of normal and pathological mood states.