Strong scalability indexes for a new self-rating scale for mania and depression

Abstract

The Affective Self Rating Scale (AS-18) was developed in response to clinical need for a user friendly self-rating scale for simultaneous assessment of depression, mania and mixed affective states in outpatient settings. The two subscales of AS-18 have nine items each (AS-18-M and AS-18-D). There are five levels of response categories graded from 0 to 4. AS-18 has been evaluated in two samples of bipolar 1 patients, using the non-parametric Mokken method. The Mokken method was especially developed for analysis of scales of ordinal type and gives scalability indexes that are measures of the ability of items and a full scale to rank persons according to their total score on a common dimension (unidimensionality).

The AS-18 have in two samples shown scalability indexes above the generally accepted cut-offs of ≥ 0.3 for items and ≥ 0.5 for a strong full scale.

Conclusion

AS-18 has good basic psychometric properties. It takes only a few minutes for patients to perform and is suitable for routine use in outpatients with bipolar 1 disorder.