Table 3.

Studies addressing the link between sleep and psychotic experiences in non-clinical populations.

Citation	Design	N	Sample characteristics	Psychosis measure(s)	Sleep dysfunction measure(s)	Comment on findings	Linked?
(Fisher et al. (2014)	Longitudinal	6796	Children (aged 12) from population cohort (ALSPAC)	Psychotic experiences PLIKSi	Sleep disorder symptoms Postal questionnaires (completed by mothers) at age 2.5, 3.5, 4.75, 6.75, and 9 years. Sleep problems at 12 years assessed in semi-structured diagnostic-based interview with child.	Children with more frequent nightmares between 2.5 and 9 years more likely to report psychotic experiences at age 12. Children reporting any parasomnia at age 12 also found to have higher rates of psychotic experiences.	Y
Freeman et al. (2009)	Cross-sectional	300	Convenience sample from community	Paranoia G-PTS	Insomnia symptoms ISI, Sleep-50	Insomnia associated with paranoid thinking, association partly accounted for by anxiety and depression.	Y
Freeman, Brugha, et al. (2010)	Cross-sectional	8580	National epidemiological survey (British National Survey of Psychiatric Morbidity)	Paranoia PSQ, SCID-II	Insomnia symptoms CIS-R	Insomnia associated with an increase in paranoid thinking, association partly accounted for by affective symptoms or cannabis use.	Y
Freeman et al. (2011)	Cross-sectional	7281	National epidemiological survey (USA — Adult Psychiatric Morbidity Survey)	Paranoia Paranoia items from survey (3)	Insomnia symptoms CIS-R	Paranoia associated with insomnia, odds ratios of insomnia diagnosis increases with level of paranoia.	Y
Freeman et al. (2012)	Longitudinal	2382	National epidemiological survey (British Psychiatric Morbidity Survey 2000)	Paranoia PSQ (3 items) SCID-II (at baseline and 18 month follow up)	Insomnia symptoms CIS-R (at baseline and 18 month follow up)	Insomnia symptoms predicted new paranoid thinking or persistence of existing paranoid thinking at 18 month follow-up.	Y
Freeman et al. (2013)	Longitudinal	106	Individuals attending hospital after an assault	Paranoia G-PTS SSPS PANSS PSYRATS 4 paranoia and threat related visual analogue scales (all at baseline and 6 month follow up)	Insomnia symptoms ISI (at baseline and 6 month follow up)	Insomnia at baseline was found to predict paranoia (G-PTS) and post-traumatic stress disorder symptoms at 6 month follow up. Current insomnia was also a significant predictor of paranoia scores at 6 months.	Y
Hurdiel et al. (2014)	Manipulation (sleep deprivation)	17	Volunteers completing ultramarathon event	Psychotic experiences Hallucinations — open ended question on completion	Objective sleep Wrist watch actigraphy throughout event Sleep deprivation Average 46 h 38 min	4 out of 17 participants reported experiencing hallucinations during the exercise event.	Y
Jeppesen et al. (2014)	Cross-sectional	1623	Adolescents (aged 11/12 years) from population cohort	Psychotic experiences: K-SADS-PL	Subjective sleep Self-report of sleep disturbance in structured interview	Likelihood of psychotic experiences increased with sleep problems and emotional or neurodevelopmental disorders. Increased prevalence of sleep disorders among children with psychotic experiences.	Y
Kahn-Greene et al. (2007)	Manipulation (sleep deprivation)	25	Non-clinical volunteers (recruited from military)	Psychotic experiences PAI (pre and post sleep deprivation)	Sleep deprivation 56 h	Sleep deprivation resulted in increase in anxiety, depression and paranoia, but not manic-related symptoms or schizophrenia symptom factors.	Y
Koyanagi and Stickley (2015)	Cross-sectional	267,692	WHO population based survey (56 countries)	Psychotic experiences Single items from CIDE for delusional mood, delusions of persecution/reference, delusions of control, hallucinations	Insomnia symptoms 1 item for presence of insomnia symptoms (5 point scale of ‘none’ to ‘extreme’)	Sleep problems associated in dose–response fashion with psychotic symptoms in almost all countries with significant ORs from 2.26–2.84 (1.54–1.68 after controlling for anxiety and depression).	Y
Lee et al. (2012)	Cross-sectional	7172	23 high school cohorts of students (aged 12–17)	Psychotic- experiences ESI Psychosis risk: Y-PARQ	Insomnia Self report questionnaire modelled on ICD-10 diagnostic criteria for insomnia Excessive Daytime Sleepiness ESS Cataplexy Single item, muscle weakness Snoring Single item, frequency of snoring	Insomnia and excessive daytime sleepiness predicted psychotic like experiences (and higher risk scores for psychosis) in adolescent group, independent of depressive symptoms.	Y
Levin and Fireman (2002)	Cross-sectional	116	Undergraduate psychology students selected for high nightmare prevalence (at least 3–10 a year) from screening survey	Psychoticism/paranoia SCL-90-R	Nightmares Dream log	Nightmare distress (not frequency) associated with paranoia, anxiety, depression. Nightmare frequency associated with psychoticism scale score.	Y
Oshima et al. (2010)	Cross-sectional	a)279 b)62	High school cohort of students (aged 12–17) a)singletons b)twin students (31 pairs)	Psychotic- experiences Custom self-report questionnaire (4 items)	Subjective sleep GHQ-12	Poor sleep associated with psychotic like experiences.	Y
Petrovsky et al. (2014)	Manipulation (sleep deprivation)	24	Student volunteers	Psychotic- experiences PSI (pre and post sleep deprivation)	Sleep deprivation Overnight sleep deprivation Sleepiness SSS at 9 pm and from 7 to 10 am following morning (6 time points in total)	Sleep deprivation induced perceptual distortions, cognitive disorganisation and anhedonia, but not mania, paranoia or delusional thinking.	Y
(Sheaves, Bebbington, et al., submitted)	Longitudinal	a)8580 b)7403 c)2046	National epidemiological surveys: a)British Psychiatric Morbidity Survey 2000 b)British Psychiatric Morbidity Survey 2007 c)British Psychiatric Morbidity Survey 2000 18 month follow up	Paranoia and hallucinations PSQ (2 items) (at baseline and 18 month follow up)	Insomnia symptoms CIS-R (at baseline and 18 month follow up)	Insomnia predicted new hallucinatory experiences at 18 month follow up. Presence of insomnia raised likelihood of reporting hallucinations cross-sectionally. All remained significant when controlling for depression, anxiety and paranoia.	Y
Taylor et al. (2015)	Cross-sectional	a) 5076 b) 5059	a)Twin pairs (aged 16) from population cohort b)parents of twins	Psychotic- experiences SPEQ	Subjective sleep PSQI Insomnia symptoms ISI	Shared genetic and environmental mechanisms for psychotic experiences and sleep disturbances – association reduced but remained significant after controlling for negative affect.	Y
Thompson et al. (2015)	Longitudinal	4270	18 year old population cohort sample (ALSPAC)	Psychotic- experiences PLIKSi (at age 12 and 18)	Sleep disorder symptoms Postal questionnaires (completed by mothers) at age 2.5, 3.5, 4.75, 6.75, and 9 years. Sleep problems at 12 years assessed in semi-structured diagnostic-based interview with child.	Nightmares at age 12 a significant predictor of psychotic experiences at age 18, remaining after adjustment for mood and other confounders.	Y

CIDI = (Kessler & Ustün, 2004); CIS-R = Clinical Interview Schedule (revised) (Lewis, Pelosi, Araya, & Dunn, 1992); ESI = Eppendorf Schizophrenia Inventory (Mass, 2000); ESS = Epworth Sleepiness Scale (Johns, 1991); GHQ-12 = 12 item version of the General Health Questionnaire (Goldberg & Williams, 1988); G-PTS = Green et al. paranoid thoughts scale (Green et al., 2008); ISI = Insomnia Severity Index (Morin, 1993); K-SADS-PL- Schedule for schizophrenia and affective disorders for school-age children, present and lifetime edition (Kaufman et al., 1997); PAI = Personality Assessment Inventory (Morey, 1991); PANSS = Positive and Negative Symptom Scale (Kay et al., 1987); PLIKSi = Psychosis-Like Symptom Interview (Horwood et al., 2008); PSI = Psychotomimetic States Inventory (Mason et al., 2008); PSQ = Psychosis Screening Questionnaire (Bebbington & Nayani, 1995); PSQI = Pittsburgh Sleep Quality Index (Buysse, Reynolds, Monk, Berman, & Kupfer, 1989); PSYRATS = Psychotic symptom rating scales (Haddock, McCarron, Tarrier, & Faragher, 1999); SCID-II = Structured Clinical Interview for DSM-IV disorder (First, Gibbon, Spitzer, Williams, & Benjamin, 1997); SCL-90-R = Symptom Checklist 90 (Revised) (Derogatis, 1994); SLEEP-50 = (Spoormaker, Verbeek, van den Bout, & Klip, 2005); SPEQ = Specific Psychotic Experiences Questionnaire (Ronald et al., 2014); SSPS = State Social Paranoia Scale (Freeman et al., 2007); SSS = Stanford Sleepiness Scale (Hoddes, Zarcone, Smythe, Phillips, & Dement, 1973); Y-PARQ = Youth Psychosis at Risk Questionnaire (Ord, Myles-Worsley, Blailes, & Ngiralmau, 2004).