Research

Mixed

Genetic predisposition for longer habitual sleep duration is causally linked to an increased risk of schizophrenia, and conversely, genetic risk for schizophrenia causes longer sleep duration, indicating a bidirectional causal relationship.

If you naturally sleep longer than average (e.g., >8-9 hours), it may be partly due to your genetics. This paper suggests a causal link between longer sleep and higher schizophrenia risk, but also that schizophrenia risk drives longer sleep. Focus on overall mental health monitoring rather than trying to force shorter sleep, as sleep duration is largely genetically fixed.

GoodSupportsHIGH confidence
two-sample Mendelian randomization highlights a bidirectional causal link with schizophrenia... longer sleep duration is causal for increased risk of schizophrenia... Conversely, MR also indicated that risk of schizophrenia is causal for longer sleep duration
Hassan S. Dashti et al. · Nature Communications · 2019

Why this rating

Large sample size (n=446,118), replication in independent cohorts, and robust Mendelian randomization analyses.

Source

Genome-wide association study identifies genetic loci for self-reported habitual sleep duration supported by accelerometer-derived estimates

Hassan S. Dashti et al. · Nature Communications · 2019

DOI 10.1038/s41467-019-08917-4

cohort · n=446118Cited 649×
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DOI resolved against Crossref · corpus check 2026-06-10

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