title: Relationships between season of birth, schizotypy, temperament, character and neurocognition in a non-clinical population.
abstract: While schizophrenia has been associated with a slight excess of winter/early spring birth, it is unclear whether there is such an association in relation to schizotypal personality traits. Season of birth has also been reported to relate to temperament and character personality dimensions and cognitive functioning. Moreover, non-clinical schizotypy has been shown to be associated with mild cognitive impairment, although its precise nature is yet to be elucidated. Here we examined the relationships between season of birth, schizotypal traits, temperament and character, and cognitive function. Four hundred and fifty-one healthy adults completed the Schizotypal Personality Questionnaire (SPQ). The Temperament and Character Inventory (TCI) and a neuropsychological test battery consisting of full versions of the Wechsler Memory Scale-Revised and the Wechsler Adult Intelligence Scale-Revised, and the Wisconsin Card Sorting Test, were also administered to most of the participants. The total SPQ score of those born in winter was significantly higher than that of the remaining participants. Season of birth was not significantly associated with any of the TCI dimensions or cognitive test results. Significant but mild relationships between higher SPQ scores and lower scores on some aspects of IQ were observed. These results support the notion that schizotypy and schizophrenia are neurodevelopmental conditions on the same continuum.
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. hori@ncnp.go.jp
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hori
authors.forename: Toshiya
authors.initials: T
authors.lastname: Teraishi
authors.forename: Daimei
authors.initials: D
authors.lastname: Sasayama
authors.forename: Junko
authors.initials: J
authors.lastname: Matsuo
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kawamoto
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kinoshita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kunugi
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D036801:Parturition; D010555:Personality Inventory; D012189:Retrospective Studies; D012569:Schizotypal Personality Disorder / Q000503:physiopathology* / Q000523:psychology*; D013223:Statistics as Topic; D013694:Temperament; D055815:Young Adult