Treatment resistant depression and Axis I co-morbidity

Background. Treatment resistant depression (TRD) continues to present a for midable challenge to clinicians, accounts for over half of the annual costs associated with treatment for depression and causes great frustration to p atients. Although there have been studies attempting to define TRD, little information is available as to the cause of TRD. One suggestion is that pat ients with TRD have a greater frequency of co-morbid psychiatric disorders, which explains their resistance to standard antidepressant treatments. The objective of this study was to compare the co-morbidity of Axis I disorder s between a sample of TRD patients and a sample of non-TRD patients. Methods. TRD and non-TRD patients, recruited from two separate antidepressa nt treatment studies, were assessed for Axis I co-morbidity using the SCID- P for the DSM-III-R. Patients for the two samples were then matched for bas eline HAM-D-17 total score and gender. Results. Results reveal that non-TRD patients had a higher rate of both lif etime and current generalized anxiety disorder co-morbidity than did the TR D patients. No other statistically significant differences in Axis I co-mor bidity were found. Conclusions. These findings do not support the idea that current or lifetim e Axis I co-morbidity is more common in TRD than non-TRD patients. In fact, the only statistical difference showed non-TRD patients with higher co-mor bidity rates.