Tridimensional personality questionnaire and treatment response in major depressive disorder: a negative study

Background: Recent studies have found that the Tridimensional Personality Questionnaire can be used to help predict antidepressant treatment response in depressed outpatients. As this finding could be of great clinical importance, we attempted to replicate these findings. Methods: Our study included 199 outpatients with major depressive disorder in an 8-week open trial with fluoxetine 20 mg/day. The Tridimensional Personality Questionnaire (TPQ) was administered to all patients before treatment. Results: There was a significant correlation between pre-treatment scores on the TPQ subscale of harm avoidance and severity of depression at baseline as determined by Hamilton Depression Rating Scale-17 (HAM-D-17) scores. There was no correlation of harm avoidance scores and percent improvement of HAM-D-17 after treatment with fluoxetine. There was also no correlation of baseline HAM-D-17 scores or percent improvement with the subscales of reward dependence and novelty seeking. Limitations: Our study’s limitations include a possible selection bias, lack of controls and fixed dosing of fluoxetine. Conclusions: In contrast to previous studies, we failed to find a relationship between temperament type as defined by the TPQ and antidepressant response. Our failure to replicate the findings of other studies may in large part be related to the use of different classes of antidepressants. Further studies using similar antidepressants may be helpful to clarify this discrepancy.