IQ and risk for schizophrenia: a population-based cohort study

Abstract

The results confirm the importance of low intellectual ability as a risk factor for schizophrenia and other psychoses. This is unlikely to be due to prodromal decline or known confounders. The association could be directly causal with cognitive impairment leading to false beliefs and perceptions, or could be indirect with any factors causing lower IQ, such as abnormal brain development increasing the risk for schizophrenia.