Insomnia, Nightmares, and Chronotype as Markers of Risk for Severe Mental Illness: Results from a Student Population.
OBJECTIVE
To group participants according to markers of risk for severe mental illness based on subsyndromal symptoms reported in early adulthood and evaluate attributes of sleep across these risk categories.


METHODS
An online survey of sleep and psychiatric symptomatology (The Oxford Sleep Survey) was administered to students at one United Kingdom university. 1403 students (undergraduate and postgraduate) completed the survey. The median age was 21 (interquartile range = 20-23) and 55.60% were female. The cross-sectional data were used to cluster participants based on dimensional measures of psychiatric symptoms (hallucinations, paranoia, depression, anxiety, and (hypo)mania). High, medium, and low symptom groups were compared across sleep parameters: insomnia symptoms, nightmares, chronotype, and social jet lag.


RESULTS
Insomnia symptoms, nightmares frequency, and nightmare-related distress increased in a dose-response manner with higher reported subsyndromal psychiatric symptoms (low, medium, and high). The high-risk group exhibited a later chronotype (mid sleep point for free days) than the medium- or low-risk group. The majority of participants (71.7%) in the high-risk group screened positive for insomnia and the median nightmare frequency was two per 14 days (moderately severe pathology).


CONCLUSIONS
Insomnia, nightmares, and circadian phase delay are associated with increased subsyndromal psychiatric symptoms in young people. Each is a treatable sleep disorder and might be a target for early intervention to modify the subsequent progression of psychiatric disorder.
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
Bryony
B
Sheaves
Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, UK.
Kate
K
Porcheret
Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford; Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK.
Athanasios
A
Tsanas
Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, UK.
Colin A
CA
Espie
Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, UK.
Russell G
RG
Foster
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
Daniel
D
Freeman
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
Paul J
PJ
Harrison
Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, UK.
Katharina
K
Wulff
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
Guy M
GM
Goodwin
D001007:Anxiety / Q000150:complications; D001714:Bipolar Disorder / Q000150:complications; D003430:Cross-Sectional Studies; D003863:Depression / Q000150:complications; D003866:Depressive Disorder / Q000150:complications; D018450:Disease Progression; D004198:Disease Susceptibility; D004325:Dreams / Q000523:psychology*; D005260:Female; D006801:Humans; D020179:Jet Lag Syndrome / Q000150:complications* / Q000523:psychology*; D008297:Male; D001523:Mental Disorders / Q000150:complications*; D010259:Paranoid Disorders / Q000150:complications; D012306:Risk; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000523:psychology*; D013334:Students / Q000523:psychology*; D011795:Surveys and Questionnaires; D006113:United Kingdom; D014495:Universities; D055815:Young Adult
chronotype; cluster analysis; insomnia; nightmares; severe mental illness; sleep; social jet lag