CIRCADIAN TYPOLOGY AND INDIVIDUAL-DIFFERENCES - A REVIEW

This paper reviews studies which have dealt with the relationship betw een morningness-eveningness (circadian typology) and other individual differences such as age, sex, personality dimensions and work schedule of their subjects. It appeared that the changes in the morningness-ev eningness preference covaried with the age related changes in the inte rnal body clock. An older age was associated with morningness while yo unger subjects tended towards eveningness, the critical age for the ci rcadian typology change was 50 years. Sex-related differences are too small to be reflected in the scores on circadian typology questionnair es, although women were ahead of men by 1 hr in their circadian rhythm s. The results on work schedule proved its role as a synchronizer modi fying the morningness factor. The morningness dimension and extraversi on are probably related through the impulsivity subdimension, which is closely associated with brain activation. Further research is needed to clarify the relationship between morningness and other personality dimensions (neuroticism, psychoticism), because the results are inconc lusive. The influence of circadian typology on the tolerance to shift work and life habits are also discussed. The results with regard to sh ift work revealed the importance of morningness in determining human t olerance and health complaints. As regards life habits, there were dif ferences in various aspects related to circadian typology especially p sychoactive substances consumption.