Phenotypic divergence in sleep and circadian cycles linked by affective state and environmental risk related to psychosis.

STUDY OBJECTIVES: Environmental cues influence circadian rhythm timing and neurochemicals involved in the regulation of affective behavior. How this interplay makes them a probable nonspecific risk factor for psychosis is unclear. We aimed to identify the relationship between environmental risk for psychosis and circadian timing phenotypes sampled from the general population. METHODS: Using an online survey, we devised a cumulative risk exposure score for each of the 1898 survey respondents based on 23 empirically verified transdiagnostic risks for psychosis, three dimensions of affect severity, psychotic-like experiences, and help-seeking behavior. Quantitative phenotyping of sleep and circadian rhythms was undertaken using at-home polysomnography, melatonin and cortisol profiles, and 3-week rest-activity behavior in individuals with a high-risk exposure load (top 15% of survey respondents, n = 22) and low-risk exposure load (bottom 15% of respondents, n = 22). RESULTS: Psychiatric symptoms were present in 100% of the high-load participants and 14% of the low-load participants. Compared to those with a low-load, high-load participants showed a later melatonin phase which was reflected by a greater degree of dispersion in circadian timing. Phase relationships between later circadian melatonin phase and later actigraphic sleep onsets were maintained and these were strongly correlated with self-reported sleep mid-points. No differences were identified from polysomnography during sleep between groups. CONCLUSION: Distinguishing circadian timing from other sleep phenotypes will allow adaptation for dosage of time-directed intervention, useful in stabilizing circadian timekeeping physiology and potentially reducing the multisystemic disruption in mental health disorders.

Do environmental risk factors for the development of psychosis distribute differently across dimensionally assessed psychotic experiences?

Psychotic experiences (PE) are associated with poorer functioning, higher distress and the onset of serious mental illness. Environmental exposures (e.g. childhood abuse) are associated with the development of PE. However, which specific exposures convey risk for each type or dimension of PE has rarely been explored. The Oxford Wellbeing Life and Sleep (OWLS) survey includes 22 environmental risk factors for psychosis and was designed to examine how environmental risks are associated with specific dimensions of PE. Multivariate logistic regression models were fit using these risk factors to predict six dimensions of PE (perceptual abnormalities, persecutory ideation, bizarre ideas, cognitive disorganisation, delusional mood and negative symptoms). Models were built using only 70% of the data, and then fit to the remaining data to assess their generalisability and quality. 1789 (27.2% men; mean age = 27.6; SD = 10.9) survey responses were analysed. The risk factors predictive of the most PE were anxiety, social withdrawal during childhood and trauma. Cannabis and depression predicted three dimensions with both predicting bizarre ideas and persecutory ideation. Psychological abuse and sleep quality each predicted two dimensions (persecutory ideation and delusional mood). Risk factors predicting one PE dimension were age (predicting cognitive disorganisation), physical abuse (bizarre ideas), bullying and gender (persecutory ideation); and circadian phase (delusional mood). These results lend support for a continuum of psychosis, suggesting environmental risks for psychotic disorders also increase the risk of assorted dimensions of PE. Furthermore, it advocates the use of dimensional approaches when examining environmental exposures for PE given that environmental risks distribute differently across dimensions.

Revisiting nocturnal heart rate and heart rate variability in insomnia: A polysomnography-based comparison of young self-reported good and poor sleepers.

Primary insomnia is often considered a disorder of 24-hr hyperarousal. Numerous attempts have been made to investigate nocturnal heart rate (HR) and its variability (HRV) as potential pathophysiological hallmarks of altered arousal levels in insomnia, with mixed results. We have aimed to overcome some of the pitfalls of previous studies by using a young, medication-free, age- and gender-matched population consisting of 43 students aged 18-30 years half with a subthreshold insomnia complaint. We employed at-home ambulatory polysomnography and compared this attenuated insomnia group to a good sleeping group. The poor sleepers had significantly higher wake after sleep onset, arousal count, mean HR in all sleep stages (with the exception of Stage 1) and lower sleep efficiency. Consistent with previous research, we also found a significant group-by-sleep stage interaction in the prediction of nocturnal HR, highlighting the insomnia group to have a lower wake-sleep HR reduction compared to good sleepers. When restricting our analyses to insomnia with objectively determined short sleep duration, we found significantly lower standard deviation of RR intervals (SDNN; a measure of HRV) compared to good sleepers. Taken together, this lends credence to the hyperarousal model of insomnia and may at least partially explain the increased prevalence of cardiovascular morbidity and mortality observed in patients with insomnia.

Pain and sleep problems predict quality of life for veterans with serious mental illness.

PURPOSE: Poor sleep and pain are common in veterans with serious mental illness (SMI), yet it is unclear how these may impact dimensions of quality of life. As such, this study examined independent and additive contributions of sleep and pain difficulties on quality of life (QoL) among a sample of veterans with SMI and insomnia. METHOD: Participants were 57 veterans with SMI (schizophrenia spectrum, bipolar, or major depressive disorders with significant functional impairment) and at least subthreshold insomnia (Insomnia Severity Index ≥8). Measures assessed sleep quality (Pittsburgh Sleep Quality Index), pain intensity (Pain Numeric Rating Scale [PNRS]), pain interference (Short Form 12 Health Survey), and QoL (World Health Organization Quality of Life-BREF). Multivariate multiple regression analyses examined the effects of sleep quality and pain on QoL. RESULTS: Forty-one veterans (71.9%) reported moderate-to-severe pain (PNRS ≥4). Poorer sleep quality was associated with greater pain interference and worse physical, emotional, and environmental QoL. Sleep quality, not pain, explained significant variance in environmental QoL (b = -2.30; 95% confidence interval [CI: -4.16, -.43]). Pain interference, not sleep quality, explained significant variance in physical health-related QoL (b = -.23; 95% CI [-.38, -.08]). CONCLUSIONS: Results reveal the importance of screening for insomnia and chronic pain among veterans with SMI. For these veterans who already struggle with daytime functioning, interventions such as integrated cognitive-behavioral therapy for pain-related insomnia are warranted. Such treatments must account for how sleep disturbance and chronic pain may differentially impact multiple facets of QoL. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Schizotypy and Performance on an Insight Problem-Solving Task: The Contribution of Persecutory Ideation.

Insight problem solving is thought to underpin creative thought as it incorporates both divergent (generating multiple ideas and solutions) and convergent (arriving at the optimal solution) thinking approaches. The current literature on schizotypy and creativity is mixed and requires clarification. An alternate approach was employed by designing an exploratory web-based study using only correlates of schizotypal traits (paranoia, dissociation, cognitive failures, fantasy proneness, and unusual sleep experiences) and examining which (if any) predicted optimal performance on an insight problem-solving task. One hundred and twenty-one participants were recruited online from the general population and completed the number reduction task. The discovery of the hidden rule (HR) was used as a measure of insight. Multivariate logistic regression analyses highlighted persecutory ideation to best predict the discovery of the HR (OR = 1.05; 95% CI 1.01-1.10, p = 0.017), with a one-point increase in persecutory ideas corresponding to the participant being 5% more likely to discover the HR. This result suggests that persecutory ideation, above other schizotypy correlates, may be involved in insight problem solving.

Sleep, circadian rhythms, and schizophrenia: where we are and where we need to go.

PURPOSE OF REVIEW: The review is designed to give an overview of the latest developments in research exploring the relationship between sleep and psychosis, with particular attention paid to the evidence for a causal relationship between the two. RECENT FINDINGS: The most interesting avenues currently in pursuit are focused upon sleep spindle deficits which may hallmark an endophenotype; explorations of the continuum of psychotic experiences, and experimental manipulations to explore the evidence for bidirectional causality; inflammatory markers, psychosis and sleep disturbances and finally, treatment approaches for sleep in psychosis and the subsequent impact on positive experiences. SUMMARY: Globally, large surveys and tightly controlled sleep deprivation or manipulation experiments provide good evidence for a cause-and-effect relationship between sleep and subclinical psychotic experiences. The evidence for cause-and-effect using a interventionist-causal model is more ambiguous; it would appear treating insomnia improves psychotic experiences in an insomnia cohort but not in a cohort with schizophrenia. This advocates the necessity for mechanism-driven research with dimensional approaches and in depth phenotyping of circadian clock-driven processes and sleep regulating functions. Such an approach would lead to greater insight into the dynamics of sleep changes in healthy and acute psychosis brain states.

The interaction between subclinical psychotic experiences, insomnia and objective measures of sleep.

Investigations into schizophrenia have revealed a high incidence of comorbidity with disturbed sleep and circadian timing. Acknowledging this comorbidity on a dimensional level, we tested prospectively whether subclinical psychotic symptoms are more prevalent in individuals with insomnia. An insomnia group (n=21) and controls (n=22) were recruited on their subjective sleep quality, recorded actigraphically for 3weeks and assessed for psychotic-like experiences with The Prodromal Questionnaire-16. Using multivariate Poisson regression analyses, we found that objective and subjective sleep measures interact to predict the highest risk for psychotic experiences. Objective measures of sleep and statistical modelling are rarely used in either clinical trials or practice for schizophrenia, yet this study highlights their value in these areas.

Sleep on Long Haul Layovers and Pilot Fatigue at the Start of the Next Duty Period.

INTRODUCTION: Layovers are critical for pilot recovery between flights and minimum layover durations are required by regulation. However, research on the factors affecting layover sleep and safety performance indicators (SPIs) before subsequent flights is relatively sparse. The present project combined data from 6 studies, including 8 long-range and 5 ultra-long range out-and-back trips across a range of different layover destinations (299 pilots in 4-person crews, 410 layovers, 1-3 d layover duration). METHODS: Sleep was monitored via actigraphy from 3 d pre-trip to at least 3 d post-trip. Pilots rated their sleepiness (Karolinska Sleepiness Scale, KSS) and fatigue (Samn-Perelli scale, SP) at duty start for the inbound flight. Mixed model ANOVAs identified independent associations between fatigue and sleepiness SPIs and operational factors (domicile time of duty start for the inbound flight in six 4-h bins, layover duration, and total sleep time (TST) in the 24 h prior to inbound duty start). RESULTS: TST was greatest on layovers ending between 1200-1559 domicile time (time in the city from which the outbound flight departed) and TST was a significant predictor of both KSS and SP ratings at duty start for the inbound flight. DISCUSSION: TST in the 24 h prior to the inbound flight was greatest when duty start time allowed for the inclusion of a full domicile night time period. In this dataset, circadian end-time of layovers is a key determinant of pilot fatigue status at the beginning of the inbound duty period.Cosgrove J, Wu LJ, van den Berg M, Signal TL, Gander PH. Sleep on long haul layovers and pilot fatigue at the start of the next duty period. Aerosp Med Hum Perform. 2018; 89(1):19-25.

Imagining the impossible before breakfast: the relation between creativity, dissociation, and sleep.

Dissociative symptoms have been related to higher rapid eye movement sleep density, a sleep phase during which hyperassociativity may occur. This may enhance artistic creativity during the day. To test this hypothesis, we conducted a creative photo contest to explore the relation between dissociation, sleep, and creativity. During the contest, participants (N = 72) took one photo per day for five consecutive days, based on specific daily themes (consisting of single words) and the instruction to take as creative a photo as possible each day. Furthermore, they completed daily measures of state dissociation and a short sleep diary. The photos and their captions were ranked by two professional photographers and two clinical psychologists based on creativity, originality, bizarreness, and quality. We expected that dissociative people would rank higher in the contest compared with low-dissociative participants, and that the most original photos would be taken on days when the participants scored highest on acute dissociation. We found that acute dissociation predicted a higher ranking on creativity. Poorer sleep quality and fewer hours of sleep predicted more bizarreness in the photos and captions. None of the trait measures could predict creativity. In sum, acute dissociation related to enhanced creativity. These findings contribute to our understanding of dissociative symptomatology.