Findings from twin analyses demonstrated a genetic overlap between sleep disturbances and psychotic like experiences and a genetic correlation has also been reported between schizophrenia and the risk for nightmares in childhood. A prospective birth cohort study — the Avon Longitudinal Study of Parents and Children (ALSPAC) — was conducted in the United Kingdom and the results were published in the journal Wellcome Open Research.
Recognizing that sleep abnormalities are common in patients with schizophrenia but that the mechanisms behind this link are unclear, the investigators sought to explore whether the genetic risk for schizophrenia is associated with sleep phenotypes. They used data from 6058 children and 2302 mothers from ALSPAC. The researchers evaluated the links between a polygenic risk score for schizophrenia and sleep duration in both children and mothers, as well as nightmares in children, together with genetic covariances between the 2 trials.
The polygenic risk for schizophrenia was associated with a significantly increased risk for nightmares in children (odds ratio 1.07; 95% CI, 1.01-1.14; P =.02), as well as with less sleep (β=44.52; 95% CI, −88.98 to −0.07; P =.05). Although a similar relationship was observed with respect to sleep duration in mothers, the evidence supporting this link was much weaker (P =.38).
The researchers also found genetic covariance between the risk for schizophrenia and reduced sleep duration in both children and mothers, as well as between the risk for schizophrenia and nightmares in children.
The investigators concluded that although the findings from these dual analyses provide evidence of some underlying shared genetic mechanism between sleep phenotypes and schizophrenia, they do no permit a determination of the reason for this association. It is possible that the findings are the result of horizontal pleiotropy, in which genetic variants linked to schizophrenia are also independently linked to sleep phenotypes. It is also possible, however, that the findings might result from causality, with either liability to schizophrenia causing a disruption to sleep or sleep disruption causing schizophrenia.
Reed ZE, Jones HJ, Hemani G, Zammit S, Davis OSP. Schizophrenia liability shares common molecular genetic risk factors with sleep duration and nightmares in childhood. Version 2. Wellcome Open Res. 2019;4:15.