Polygenic Risk Scores, School Achievement and Risk for Schizophrenia: A Danish Population-based Study
Cognitive impairments often manifest premorbidly during adolescence with the largest effect observed for IQ. Poorer school achievement (a proxy for IQ) is probably linked with the risk of later of schizophrenia but large scale epidemiological studies are needed to examine possible genetic underpinnings of this association.
About the study
In a case-cohort study based on a Danish population sample (1470 with schizophrenia and 7318 sub-cohort non-cases) we examined if school achievement (in 9th grade) is associated with the risk of later schizophrenia and the possible effects of polygenic risk scores on this association. We hypothesized that polygenic risk score for schizophrenia or polygenic risk score for cognition confounded the association. We obtained genome-wide data, school performance, and family psychiatric and socioeconomic background information from national registers and neonatal biobanks.
Facts about the study
- We found that poor school performance prior to the typical age of onset of schizophrenia strongly predicted increased risk of schizophrenia later in life
- We also found that higher PRS (polygenic score) for educational attainment predicted better primary school performance in the general population and explained 7.6% of its variance
- We found no convincing evidence that higher PRS for schizophrenia was associated with poorer school performance in cases or in non-cases
- Neither polygenic risk score for schizophrenia nor PRS for educational attainment explained (confounded) the “school-schizophrenia association” in our study. Other factors related to family psychiatric and socioeconomic background information did, however, explain some of the association.
- Further study is needed to examine if PRS for schizophrenia mediates somatic comorbidity with schizophrenia (i.e. increased school absence could be explained by somatic morbidity).
The article "Polygenic Risk Scores, School Achievement and Risk for Schizophrenia: A Danish Population-based Study" was published in Biological Psychiatry. 2018.
Further information
Holger Jelling Sørensen, Mental Health Centre Copenhagen, Capital Region of Denmark, Email: holger.jelling.soerensen@regionh.dk