Clinical and differential diagnostic aspects of treatment-resistant depression.

This study investigated treatment-resistant depressed patients. A sample of 49 patients was selected from a review of 302 patients who had been consecutively evaluated at a tertiary care facility. Clinical records of these 49 patients revealed frequent misdiagnosis of depression subtype, relatively infrequent treatment with electroconvulsive therapy, and pharmacotherapy trials which often were too brief or characterized by inadequate dosing to be effective. A group of non-treatment resistant patients was matched for age, gender, and depressive subtype with 26 treatment-resistant patients. Treatment-resistant patients were less "atypical" and were more likely to have made a suicide attempt than the comparison patients. Although depression rating scales showed similar mean ratings for both groups, the TPQ revealed higher mean ratings for harm avoidance and lower mean ratings for novelty seeking for treatment-resistant patients. The implications of these findings are discussed.