Personality Traits as Risk Factors for Treatment-Resistant Depression

Background: The clinical outcome of antidepressant treatment in patients with major depressive disorder (MDD) is thought to be associated with personality traits. A number of studies suggest that depressed patients show high harm avoidance, low self-directedness and cooperativeness, as measured on the Temperament and Character Inventory (TCI). However, the psychology of these patients is not well documented. Methods: Psychological evaluation using Cloninger's TCI, was performed on treatment-resistant MDD patients (n = 35), remission MDD patients (n = 31), and age-and gender-matched healthy controls (n = 174). Results: Treatment-resistant patients demonstrated high scores for harm avoidance, and low scores for reward dependence, self-directedness, and cooperativeness using the TCI, compared with healthy controls and remission patients. Interestingly, patients in remission continued to show significantly high scores for harm avoidance, but not other traits in the TCI compared with controls. Moreover, there was a significant negative correlation between reward dependence and harm avoidance in the treatment-resistant depression cohort, which was absent in the control and remitted depression groups. Conclusions: This study suggests that low reward dependence and to a lesser extent, low cooperativeness in the TCI may be risk factors for treatment-resistant depression.