BACKGROUND An inverse relationship between risk of schizophrenia and premorbid IQ is a robust empirical finding. Cognitive impairment may be a core feature of schizophrenia in addition to the clinical symptoms that have historically defined the disorder. AIMS To evaluate whether risk of schizophrenia increases linearly or nonlinearly with the lowering of premorbid IQ after adjustment for a range of confounding factors. METHODS IQ data from the 1958 National Child Development Study, a prospective national birth cohort (n = 17 419), were linked with psychiatric admissions in England and Wales over a 20-year period. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnoses were derived from case notes. RESULTS A clear nonlinear inverse relationship between general intelligence at ages 7 and 11 and risk of adult psychosis was found even after adjustment for potential social, behavioral, or demographic confounding factors. No such relationship was found for affective disorders. CONCLUSIONS The nonlinear relationship suggests an excess risk of schizophrenia in children with premorbid IQ in the learning disabilities range. Previous reports of a linear relationship are likely to be a result of less sensitive statistical methods for detecting nonlinearity.

中文翻译：

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1958 年英国出生队列中成人精神分裂症的风险及其与儿童智商的关系。

背景精神分裂症风险与病前智商之间的反比关系是一项强有力的实证发现。除了历史上定义该疾病的临床症状之外，认知障碍可能是精神分裂症的核心特征。目的 评估在调整一系列混杂因素后，精神分裂症的风险是否随着病前 IQ 的降低呈线性或非线性增加。方法 1958 年全国儿童发展研究（一项前瞻性全国出生队列（n = 17 419））的 IQ 数据与英格兰和威尔士 20 年间的精神病入院率相关。《精神疾病诊断和统计手册》第四版的诊断来自病例记录。结果 即使在调整了潜在的社会、行为或人口统计学混杂因素后，7 岁和 11 岁的一般智力与成人精神病风险之间仍存在明显的非线性负相关。在情感障碍中没有发现这种关系。结论 非线性关系表明，在学习障碍范围内，具有病前智商的儿童患精神分裂症的风险过高。以前关于线性关系的报告很可能是由于检测非线性的统计方法不太敏感。