Previous studies on the Tridimensional Personality Questionnaire (TPQ) in patients with panic disorder (PD) have failed to support Cloninger's hypothesis that PD is not specifically related to any of the 3 personality dimensions. In most studies, patients with PD had clearly higher harm avoidance (HA) scores. This finding, however, could be biased by comorbid personality disorders in the samples. In the present study, we examined the TPQ scores in 43 patients without comorbid personality disorders.The differences between PD patients without personality disorders and control subjects were examined by hierarchical analyses of variance.We found that PD patients without personality disorders had higher HA scores than control subjects, whereas significant differences were not demonstrated for the novelty seeking and reward dependence dimensions.Our results indicate that repeated demonstrations of elevated HA scores in patients with PD are not crucially influenced by comorbid personality disorders.