Objective: We used the Tridimensional Personality Questionnaire (TPQ) to study the relationship between temperamental traits and comorbid anxiety disorders as well as age of onset of major depressive disorder (MDD) in 263 patients with MDD.
Methods: Patients recruited for a large clinical study on MDD underwent a Structured Clinical Interview for DSM-III-R assessment and were administered the self-rated TPQ [mean age = 39.5 +/- 10.5 years, women = 138 (53%), initial 17-item Hamilton Rating Scale for Depression (HAM-D-17) score = 19.6 +/- 3.4]. The TPQ was scored for three previously identified factors -- harm avoidance (HA), novelty seeking (NS), and reward dependence (RD). Multiple linear regression methods were used to evaluate the relationship between TPQ factors and each comorbid anxiety disorder as well as between early-- vs. late-onset MDD, after controlling for age, gender and initial HAM-D-17 score (when these were related to the dependent variable in simple regressions).
Results: Social anxiety disorder in MDD was strongly associated with higher scores on HA and lower scores on NS and RD (t = 5.4, p < 0.0001; t = 2.6, p = 0.009; t = 2.2, p = 0.028, respectively). A diagnosis of generalized anxiety disorder in MDD was significantly related to higher HA scores (t = 2.8, p = 0.006). The presence of comorbid obsessive-compulsive disorder was associated with lower NS scores (t = 2.3, p = 0.023) as was that of comorbid panic disorder (t = 2.0, p = 0.051). Finally, the presence of simple phobias was associated with lower scores on RD (t = 2.4, p = 0.016). HA scores were higher in patients with early onset of MDD (adjusted p = 0.05). Early versus late onset of MDD was not significantly related to NS or RD scores.
Limitations: Since our sample consisted of moderately depressed outpatients, our ability to generalize our findings to other populations is limited.
Conclusions: Features of temperament are related to patterns of anxiety disorder comorbidity and age of onset among patients with MDD. Higher levels of HA and lower levels of RD and NS were associated with an increased risk of anxiety disorder comorbidity in our sample. HA may also be related to early onset of depression.