Novelty seekers and impulsive subjects are low in morningness.

The bipolar dimension of morningness-eveningness refers to the preferred times of day for achieving various activities (i.e. the phase of the circadian clock). It is validated from a biological point of view, associated with at least one gene and heritable through an epistatic mechanism. It has been used as a proxy to study the relationships between the circadian system, personality and psychopathology: there is a correlation between the evening orientation and depression, extraversion and, probably, impulsivity. Furthermore, there is a possible relationship with temperament in children as theorized by Thomas and Chess. In this paper, we expanded on the hypothesis that impulsive subjects are low in morningness by performing a factor analysis of the Composite Scale of Morningness, Cloninger's temperament and character inventory, and Spielberger's trait anxiety inventory in a sample of 129 males. The results can probably be extended to women. Morningness is negatively correlated with novelty seeking (which includes an impulsivity facet), positively correlated with persistence, and independent of character dimensions and trait anxiety. Future research may focus in the involvement of the circadian system in these personality dimensions and facets, and the benefits of adding chronotherapic manipulations in the treatment of the personality disorders.