精神分裂病と出生時体重—母子手帳を用いた調査から

Birth Weight in Schizophrenia: a study using “Maternal and Child Health Handbook”

　【抄録】近年，精神分裂病の病因に関し神経発達論的成因仮説が注目されている。本研究では精神分裂病者の母胎内での発達を検証することを目的とし，精神分裂病者（DSM-Ⅲ-R）とその健康同胞の出生時体重を「母子手帳」を用いて調査し比較した。また，精神病の遺伝負因の有無によって差があるか否かに関しても調べた。39組の同胞間の比較では，出生時体重において有意差を認めなかった。しかし，65名の精神分裂病者の中で遺伝負因を持つ者（N＝52）と持たない者（N＝13）とを比較すると，前者は後者より有意に軽かった。以上から，精神分裂病に対する脆弱性を与える遺伝的要因は胎内発達に影響を与え，低出生時体重に反映される可能性が示唆された。

　We compared the birth weight of 39 schizophrenics (DSM-Ⅲ-R) and their 39 healthy siblings, using paired t-test. No significant difference was found between the two groups. However, when birth weight was examined in relation to family history of psychosis among 65 schizophrenics, individuals with a family history (N=13) had significantly lower birth weights than those without a family history (N=52). Analysis of covariance controlling for several potential confounders (sex, birth order, gestational age, birth year, maternal body weight, and maternal age at delivery) also revealed that family history was significantly associated with birth weight. Further analysis with multiple regression revealed that there was a 262g (95% confidential interval: 115-493) reduction of birth weight in familial schizophrenics when compared with non-familial schizophrenics. These results suggest that genetic susceptibility to schizophrenia is associated with impaired prenatal growth which results in lower birth weight.