Further evidence on the relationship between dopamine and novelty seeking: a neuroendocrine study

In the biosocial model of Cloninger, three major personality dimensions, novelty seeking (NS), harm avoidance (HA), and reward dependence (RD) are dependent on central monoaminergic systems, respectively dopaminergic, serotonergic, and noradrenergic. This study investigated the relationships between these major personality dimensions and growth hormone (GH) responses to both apomorphine and clonidine challenge tests in healthy subjects. GH responses to apomorphine were significantly correlated with NS when peak relative values were considered (r=0.47, P=0.03). HA and RD did not show any relationships with the endocrine responses. In contrast, no significant relationship existed between GH responses to clonidine and any of the three temperament dimensions. These results gave another support of the hypothesized link between NS and dopaminergic central neurotransmission. In contrast, the results did not confirm the association between RD and noradrenergic central neurotransmission, probably because RD is poorly validated. This partial confirmation might suggest that the link between personality traits and neurotransmission systems is probably indirect.