Date of Award


Degree Type


Degree Name

Master of Science in Psychology

Committee Chair

James B. Lane, PhD


Creative Commons License
This work is licensed under a Creative Commons Attribution-No Derivative Works 3.0 License.


Mood disorders represent a major health burden for society and impact individuals' ability to function socially and professionally. Recent research has challenged the Current DSM-IV-TR categorical diagnostic system for unipolar and bipolar mood disorders. This thesis reviews existing research in support of both categorical and dimensional models of mood disorder. A dimensional model appears to be supported based on current research. This thesis proposes a two-dimensional model of mood disorder and suggests directions for future research. It is anticipated that the. acceptance of a dimensional model of mood disorders might lead to changes in assessment, diagnosis; and treatment of mood disorders.