Objective: To present the psychometric properties of the Nepean Dysphoria Scale (NDS), the first instrument developed to measure the severity of dysphoria.
Method: The NDS was administered to 134 university students and its characteristics were examined. The structure of the scale was investigated using exploratory factor analysis. Convergent and divergent validity were examined by investigating the associations between the NDS and its subscales with other conceptually similar (Beck Depression Inventory II, Dysfunctional Attitude Scale - Form A and Toronto Alexithymia Scale) and conceptually distinct (Anxiety Sensitivity Index) instruments.
Results: The 24-item NDS demonstrated excellent internal consistency. A four-factor solution was derived, with factors pertaining to irritability, discontent, surrender and interpersonal resentment. There were medium to strong correlations between the NDS and its subscales and depressive symptoms as measured by the Beck Depression Inventory II. The NDS and its subscales showed weaker, but still significant, correlations with Dysfunctional Attitude Scale -Form A, Toronto Alexithymia Scale and Anxiety Sensitivity Index.
Conclusions: The study suggests that the NDS has good psychometric properties. Further research would more firmly establish the NDS as a valid measure of the complex emotional state of dysphoria.