Impulsivity but not venturesomeness is related to morningness.

The Composite Scale of Morningness (CSM) is a psychometrically sound instrument available in several languages, including French, aimed at arranging individuals along a continuum from high "eveningness" to high "morningness." On the other hand, impulsivity is involved in many personality disorders and is thought to be orthogonal to venturesomeness, which can be seen as a component of the broader construct of sensation seeking. We hypothesized that evening-type subjects would be more impulsive than morning-types. Self-administered questionnaires were distributed to students, and only complete forms were analyzed (194 males and 358 females). A four-way analysis of covariance showed significant effects of age, gender and impulsivity, but not venturesomeness, on morningness in the sense of a higher degree of eveningness in more impulsive subjects. In addition, the correlation coefficients in both genders were similar to those reported in smaller samples. Our findings deserve further interest because, regardless of gender, they suggest a possible physiopathological approach to impulsivity that may be accessible by circadian interventions such as midday bright light exposure or pharmacological treatments.