The Temperament Scale of Novelty Seeking in adolescents shows an association with season of birth opposite to that in adults.

We investigated the relationship between season of birth and the Junior Temperament and Character Inventory of Personality (Junior TCI, JTCI) in adolescents. The Temperament Scale of Novelty Seeking (NS) is significantly higher for females born during October-January as compared to females born otherwise. This association is opposite to that obtained earlier for adults. For both genders pooled, NS is significantly higher for those born during October-March compared to April-September. This association is also found when examining the data for those of age up to 18 years in a third independent study on the age range 11-81 years with the adult TCI. There is a greater tendency for exploration and risk-taking behavior as the child individuates from the family. Our study suggests that the effects of such environmental and developmental changes on personality are different in those born during October-March as compared to those born during April-September. The former show a higher rise in NS during adolescence and a steeper fall in NS during the years of adulthood, compared to the latter. Dopamine turnover is likely associated with NS, and the mutually inhibitory systems of dopamine and melatonin are the paracrine signals of day and night, respectively. Thus, the maternal entrainment of these systems during the prenatal period, or the postnatal environmental influence on these systems, may be different for those born during the short photoperiod of October-March as compared to those born during the long photoperiod part of the year.