Cannon T D, Kaprio J, Lönnqvist J, Huttunen M, Koskenvuo M
Department of Psychology, University of Pennsylvania, Philadelphia, USA.
Arch Gen Psychiatry. 1998 Jan;55(1):67-74. doi: 10.1001/archpsyc.55.1.67.
The magnitude of heritability of schizophrenia remains controversial, due in part to limitations of estimates derived from index twin pairs exclusively. We applied structural equation modeling in a total population of twins to determine the significance and magnitudes of the genetic and environmental contributions to schizophrenia.
All monozygotic (1180 male and 1315 female pairs) and same-sex dizygotic (2765 male and 2613 female pairs) twins born from 1940 to 1957 in Finland were screened for nonorganic psychotic disorder diagnoses as recorded on an inpatient or outpatient basis or from an eligibility review for a disability pension.
The lifetime prevalence of schizophrenia was 2.0%, with a marginally higher prevalence in men (2.2%) than women (1.8%). Model fitting indicated that 83% of the variance in liability was due to additive genetic factors, and the remaining 17% was due to unique environmental factors. Sex-limitation modeling revealed no evidence of sex-specific genetic effects and no sex difference in the magnitude of heritability. A multiple threshold model incorporating affective and other psychoses as a phenotype intermediate between schizophrenia and no diagnosis was rejected.
In a population-based twin study of schizophrenia, heritability was estimated at 83%, with the remaining variance in liability attributed to environmental factors not shared in common among co-twins. Despite the notable limitation of using diagnoses ascertained through treatment contacts, the heritability estimate in this study is almost identical to those reported in recent studies of index pairs using standardized applications of DSM-III or later criteria.
精神分裂症的遗传度大小仍存在争议，部分原因在于仅从双胞胎索引对得出的估计值存在局限性。我们在双胞胎总体人群中应用结构方程模型来确定遗传和环境因素对精神分裂症的影响程度及显著性。
对1940年至1957年在芬兰出生的所有同卵双胞胎（1180对男性和1315对女性）以及同性异卵双胞胎（2765对男性和2613对女性）进行筛查，以获取住院或门诊记录的非器质性精神障碍诊断，或残疾抚恤金资格审查记录。
精神分裂症的终生患病率为2.0%，男性患病率（2.2%）略高于女性（1.8%）。模型拟合表明，易感性变异的83%归因于加性遗传因素，其余17%归因于独特环境因素。性别限制模型未显示性别特异性遗传效应的证据，遗传度大小也无性别差异。一个将情感性精神病和其他精神病作为精神分裂症与无诊断之间的中间表型纳入的多阈值模型被拒绝。
在一项基于人群的精神分裂症双胞胎研究中，遗传度估计为83%，其余易感性变异归因于双胞胎之间不共有的环境因素。尽管通过治疗接触确定诊断存在明显局限性，但本研究中的遗传度估计与近期使用DSM-III或更高标准的索引对研究报告的结果几乎相同。
