Treatment validity of the dexamethasone suppression test

This dissertation examined the value of the dexamethasone suppression test in selecting subjects who are responsive to different types of treatment for depression, thereby testing the "treatment validity" of the dexamethasone suppression test. In addition, the effects of a biologically-oriented treatment and a psychologically-oriented treatment on the dexamethasone suppression test and on subjects' dysfuntional thoughts was examined. Forty-three outpatient subjects diagnosed with Major Depression along with a high level of dysfunctional thoughts participated in this project. Subjects were identified as either abnormal or normal dexamethasone suppression test responders according to Cortisol blood levels, and then randomly assigned to receive either a biologically-oriented treatment (tricyclic antidepressant medication) or a psychologically-oriented treatment (cognitive therapy). Self-report depression measures, diagnoses, the questionnaire measuring dysfunctional thoughts, and the dexamethasone suppression test were administered at pre-intervention and post-intervention and were subjected to statistical analyses