Stress and the hypothalamic-pituitary-adrenal axis: How can the COVID-19 pandemic inform our understanding and treatment of acute insomnia?

Stress and sleep are very closely linked, and stressful life events can trigger acute insomnia. The ongoing COVID-19 pandemic is highly likely to represent one such stressful life event. Indeed, a wide range of cross-sectional studies demonstrate that the pandemic is associated with poor sleep and sleep disturbances. Given the high economic and health burden of insomnia disorder, strategies that can prevent and treat acute insomnia, and also prevent the transition from acute insomnia to insomnia disorder, are necessary. This narrative review outlines why the COVID-19 pandemic is a stressful life event, and why activation of the hypothalamic-pituitary-adrenal axis, as a biological marker of psychological stress, is likely to result in acute insomnia. Further, this review outlines how sleep disturbances might arise as a result of the COVID-19 pandemic, and why simultaneous hypothalamic-pituitary-adrenal axis measurement can inform the pathogenesis of acute insomnia. In particular, we focus on the cortisol awakening response as a marker of hypothalamic-pituitary-adrenal axis function, as cortisol is the end-product of the hypothalamic-pituitary-adrenal axis. From a research perspective, future opportunities include identifying individuals, or particular occupational or societal groups (e.g. frontline health staff), who are at high risk of developing acute insomnia, and intervening. From an acute insomnia treatment perspective, priorities include testing large-scale online behavioural interventions; examining if reducing the impact of stress is effective and, finally, assessing whether "sleep vaccination" can maintain good sleep health by preventing the occurrence of acute insomnia, by preventing the transition from acute insomnia to insomnia disorder.

The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023.

Progress in the field of insomnia since 2017 necessitated this update of the European Insomnia Guideline. Recommendations for the diagnostic procedure for insomnia and its comorbidities are: clinical interview (encompassing sleep and medical history); the use of sleep questionnaires and diaries (and physical examination and additional measures where indicated) (A). Actigraphy is not recommended for the routine evaluation of insomnia (C), but may be useful for differential-diagnostic purposes (A). Polysomnography should be used to evaluate other sleep disorders if suspected (i.e. periodic limb movement disorder, sleep-related breathing disorders, etc.), treatment-resistant insomnia (A) and for other indications (B). Cognitive-behavioural therapy for insomnia is recommended as the first-line treatment for chronic insomnia in adults of any age (including patients with comorbidities), either applied in-person or digitally (A). When cognitive-behavioural therapy for insomnia is not sufficiently effective, a pharmacological intervention can be offered (A). Benzodiazepines (A), benzodiazepine receptor agonists (A), daridorexant (A) and low-dose sedating antidepressants (B) can be used for the short-term treatment of insomnia (≤ 4 weeks). Longer-term treatment with these substances may be initiated in some cases, considering advantages and disadvantages (B). Orexin receptor antagonists can be used for periods of up to 3 months or longer in some cases (A). Prolonged-release melatonin can be used for up to 3 months in patients ≥ 55 years (B). Antihistaminergic drugs, antipsychotics, fast-release melatonin, ramelteon and phytotherapeutics are not recommended for insomnia treatment (A). Light therapy and exercise interventions may be useful as adjunct therapies to cognitive-behavioural therapy for insomnia (B).

The natural history of insomnia: Does sleep extension differentiate between those that do and do not develop chronic insomnia?

According to the "3P model" of insomnia, the variable that mediates the transition from acute insomnia (AI) to chronic insomnia is "sleep extension" (the behavioural tendency to expand sleep opportunity to compensate for sleep loss). In the present analysis, we sought to evaluate how time in bed (TIB) varies relative to the new onset of AI and chronic insomnia. A total of 1,248 subjects were recruited as good sleepers (GS). Subjects were monitored over 1 year with sleep diaries. State transitions were defined, a priori, for AI, recovered from AI (AI-REC), and for chronic insomnia (AI-CI). Two additional groupings were added based on profiles that were unanticipated: subjects that exhibited persistent poor sleep following AI (AI-PPS [those that neither recovered or developed chronic insomnia]) and subjects that recovered from chronic insomnia (CI-REC). All the groups (GS, AI-REC, AI-CI, AI-PPS and CI-REC) were evaluated for TIB differences with longitudinal mixed effects models. Post hoc analyses for the percentage of the groups that were typed as TIB "restrictors, maintainers, and expanders" were conducted using longitudinal mixed effects models and contingency analyses. Significant differences for pre-post AI TIB were not detected for the insomnia groups. Trends were apparent for the AI-CI group, which suggested that minor increases in TIB occurred weeks before the declared onset of AI. Additionally, it was found that a significantly larger percentage of AI-CI subjects engaged in sleep extension (as compared to GS). The present data suggest that transition from AI to chronic insomnia does not appear to be initiated by sleep extension and the transition may occur before the elapse of 3 months of ≥3 nights of sleep continuity disturbance. Given these findings, it may be that the mismatch between sleep ability and sleep opportunity is perpetuated over time given the failure to "naturally" engage in sleep restriction (as opposed to sleep extension).

Eye tracking and attentional bias for depressive internet memes in depression.

Previous research highlights the potential benefits of engaging with depressive internet memes for those experiencing symptoms of depression. This study aimed to determine whether: compared to non-depressed controls, individuals experiencing depressive symptoms were quicker to orient and maintain overall attention for internet memes depicting depressive content relative to neutral memes. N = 21 individuals were grouped based on the severity of reported depression symptoms using the PhQ-9. Specifically, a score of: ≤ 4 denoted the control group; and ≥ 15 the depressive symptoms group. Participants viewed a series of meme pairs depicting depressive and neutral memes for periods of 4000 ms. Data for the first fixation onset and duration, total fixation count and total fixation and gaze duration of eye-movements were recorded. A significant group x meme-type interaction indicated that participants with depressive symptoms displayed significantly more fixations on depressive rather than neutral memes. These outcomes provide suggestive evidence for the notion that depressive symptoms are associated with an attentional bias towards socio-emotionally salient stimuli.

Managing Insomnia Using Lucid Dreaming Training: A Pilot Study.

Objectives/Background: Despite Cognitive Behavioral Therapy for Insomnia (CBT-I) being considered the first-line treatment for insomnia, it is not without its challenges. As such it is worthwhile to consider, and test, alternative or adjuvant management options. Methods/Participants: The aim of the present study was to examine whether Lucid Dreaming Training for insomnia (LDT-I) impacted on insomnia, depressive and anxious symptomology in an open label trial of 48 adults with Insomnia Disorder. Participants completed the Insomnia Severity Index, General Anxiety Disorder-7 and Patient Health Questionnaire at baseline then one month following LDT-I. Training consisted of four modules delivered over a period of two consecutive weeks. Results: The results suggest, albeit preliminarily, that LDT-I may have a place within the non-pharmacological management of insomnia, as there were significant reductions in insomnia severity (t(46) = 8.16,p <.001), anxious symptomology (t(46) = 4.75,p <.001) and depressive symptomology (t(46) = 5.87,p <.001). Further, the effect size in terms of pre-post reductions on ISI scores was large (dz 1.17). Conclusions: Whilst the results are promising, further testing of LDT-I is needed to inform its place amongst the non-pharmacological treatments for insomnia.

Examination of sleep health dimensions and their associations with perceived stress and health in a UK sample.

BACKGROUND: Sleep health is a relatively new multidimensional concept, however, there is no consensus on its underlying dimensions. A previous study examined potential indicators of sleep health using an aggregated sleep health measure. However, the psychometric properties are yet to be determined. The primary aim was to assess the factor structure, reliability and validity of this measure. A secondary aim was to explore the relationships with perceived stress, and physical and mental health. METHODS: A cross-sectional online survey was conducted with 257 adults from the UK aged 18-65 (78.4% female, mean age = 29.39 [SD = 11.37]). Participants completed 13 Sleep health items, the Pittsburgh Sleep Quality Inventory, Insomnia Severity Scale, Epworth Sleepiness Scale, Perceived Stress Scale and SF-12 Health Survey. RESULTS: The measure exhibited good internal consistency (α = 0.785) and construct validity as determined by associations with existing measures. Principle components analysis produced four factors e; sleep quality (α = 0.818), sleep adaptability (α = 0.917), sleep wellness (α = 0.621) and daytime functioning (α = 0.582). Adaptability (ß = -241) was strongest predictor of perceived stress, and daytime functioning was strongest predictor of physical (ß = 0.322) and mental health (ß = 0.312). CONCLUSIONS: Sleep health is a multidimensional construct comprising four distinct but related dimensions. The importance of sleep health in terms of perceived stress and mental and physical health is highlighted.

Impaired Insulin Profiles Following a Single Night of Sleep Restriction: The Impact of Acute Sprint Interval Exercise.

Experimental sleep restriction (SR) has demonstrated reduced insulin sensitivity in healthy individuals. Exercise is well-known to be beneficial for metabolic health. A single bout of exercise has the capacity to increase insulin sensitivity for up to 2 days. Therefore, the current study aimed to determine if sprint interval exercise could attenuate the impairment in insulin sensitivity after one night of SR in healthy males. Nineteen males were recruited for this randomized crossover study which consisted of four conditions-control, SR, control plus exercise, and sleep restriction plus exercise. Time in bed was 8 hr (2300-0700) in the control conditions and 4 hr (0300-0700) in the SR conditions. Conditions were separated by a 1-week entraining period. Participants slept at home, and compliance was assessed using wrist actigraphy. Following the night of experimental sleep, participants either conducted sprint interval exercise or rested for the equivalent duration. An oral glucose tolerance test was then conducted. Blood samples were obtained at regular intervals for measurement of glucose and insulin. Insulin concentrations were higher in SR than control (p = .022). Late-phase insulin area under the curve was significantly lower in sleep restriction plus exercise than SR (862 ± 589 and 1,267 ± 558; p = .004). Glucose area under the curve was not different between conditions (p = .207). These findings suggest that exercise improves the late postprandial response following a single night of SR.

The key role of insomnia and sleep loss in the dysregulation of multiple systems involved in mood disorders: A proposed model.

Mood disorders are amongst the most prevalent and severe disorders worldwide, with a tendency to be recurrent and disabling. Although multiple mechanisms have been hypothesized to be involved in their pathogenesis, just a few integrative theoretical frameworks have been proposed and have yet to integrate comprehensively all available findings. As such, a comprehensive framework would be quite useful from a clinical and therapeutic point of view in order to identify elements to evaluate and target in the clinical practice. Because conditions of sleep loss, which include reduced sleep duration and insomnia, are constant alterations in mood disorders, the aim of this paper was to review the literature on their potential role in the pathogenesis of mood disorders and to propose a novel theoretical model. According to this hypothesis, sleep should be considered the main regulator of several systems and processes whose dysregulation is involved in the pathogenesis of mood disorders. The model may help explain why sleep disturbances are so strikingly linked to mood disorders, and underscores the need to evaluate, assess and target sleep disturbances in clinical practice, as a priority, in order to prevent and treat mood disorders.

Managing Acute Insomnia in Prison: Evaluation of a "One-Shot" Cognitive Behavioral Therapy for Insomnia (CBT-I) Intervention.

Objectives/Background: Insomnia is a serious condition that affects over 60% of the prison population and has been associated with aggression, anger, impulsivity, suicidality, and increased prison health care use. Nonpharmacological interventions for prison inmates are scarce despite the high prevalence and significant consequences of insomnia among those incarcerated. The aim of the present study was to examine the preliminary efficacy and effectiveness of a one-shot session of cognitive behavioral therapy for insomnia (CBT-I) for prison inmates with acute insomnia in an open trial. Method/Participants: The intervention consisted of one 60-70 min session of CBT-I and a self-management pamphlet. A consecutive series of 30 adult male offenders with acute insomnia from a UK prison completed measures of prospective sleep (daily sleep diary), insomnia symptoms severity (Insomnia Severity Index), and mood symptoms (Patient Health Questionnaire and General Anxiety Disorder) one week before and four weeks after receiving the intervention. Results: Pairwise t-tests revealed that a single shot of CBT-I was effective in reducing the severity of insomnia in adult male offenders (t = [29], 12.65, p < 0.001). Further, the results demonstrated moderate to large effect sizes for reductions in depressive (dRM = 0.77) and anxious (dRM = 0.83) symptoms, as well as insomnia severity (dRM = 2.35). Conclusions: A single-shot session of CBT-I is effective in managing acute insomnia and mood (depression, anxiety) symptoms in adult male prison inmates. Future research should focus on testing if the single-shot CBT-I intervention can be implemented and disseminated in other settings and populations (e.g., female and juvenile or youth offenders).

Anticipated next-day demand affects the magnitude of the cortisol awakening response, but not subjective or objective sleep.

Whilst the association between sleep and stress is well established, few studies have examined the effects of an anticipated stressor upon sleep and relevant physiological markers. The aim of the present study was to examine whether an anticipated stressor in the form of next-day demand affects subjective and objective sleep, and multiple indices of the cortisol awakening response. Subjective and objective sleep and the cortisol awakening response were measured over three consecutive nights in 40 healthy adults in a sleep laboratory. During their second night, participants were informed that they would either be required to complete a series of demanding cognitive tasks, in a competition format, during the next day (anticipation condition; n = 22), or were given no instruction (sedentary condition; n = 18). Sleep was measured subjectively using sleep diaries, objectively using polysomnography, and saliva was measured at awakening, +15, +30, +45 and +60 min each morning, from which cortisol awakening response measurement indices were derived: awakening cortisol levels, the mean increase in cortisol levels and total cortisol secretion. There were no between-group differences in subjective or objective sleep in the night preceding the anticipated demand; however, compared with the sedentary condition, those in the anticipation group displayed a larger mean increase in cortisol levels, representing the cortisol awakening response magnitude, on the morning of the anticipated demand. Overall, the results suggest that whilst anticipated stress affected the subsequent cortisol awakening response, subjective and objective sleep remained undisturbed. It is possible that the timing of an anticipated stressor, rather than its expected duration, may influence subsequent sleep disruption.

Preferential attention towards the eye-region amongst individuals with insomnia.

People with insomnia often perceive their own facial appearance as more tired compared with the appearance of others. Evidence also highlights the eye-region in projecting tiredness cues to perceivers, and tiredness judgements often rely on preferential attention towards this region. Using a novel eye-tracking paradigm, this study examined: (i) whether individuals with insomnia display preferential attention towards the eye-region, relative to nose and mouth regions, whilst observing faces compared with normal-sleepers; and (ii) whether an attentional bias towards the eye-region amongst individuals with insomnia is self-specific or general in nature. Twenty individuals with DSM-5 Insomnia Disorder and 20 normal-sleepers viewed 48 neutral facial photographs (24 of themselves, 24 of other people) for periods of 4000 ms. Eye movements were recorded using eye-tracking, and first fixation onset, first fixation duration and total gaze duration were examined for three interest-regions (eyes, nose, mouth). Significant group × interest-region interactions indicated that, regardless of the face presented, participants with insomnia were quicker to attend to, and spent more time observing, the eye-region relative to the nose and mouth regions compared with normal-sleepers. However, no group × face × interest-region interactions were established. Thus, whilst individuals with insomnia displayed preferential attention towards the eye-region in general, this effect was not accentuated during self-perception. Insomnia appears to be characterized by a general, rather than self-specific, attentional bias towards the eye-region. These findings contribute to our understanding of face perception in insomnia, and provide tentative support for cognitive models of insomnia demonstrating that individuals with insomnia monitor faces in general, with a specific focus around the eye-region, for cues associated with tiredness.

European guideline for the diagnosis and treatment of insomnia.

This European guideline for the diagnosis and treatment of insomnia was developed by a task force of the European Sleep Research Society, with the aim of providing clinical recommendations for the management of adult patients with insomnia. The guideline is based on a systematic review of relevant meta-analyses published till June 2016. The target audience for this guideline includes all clinicians involved in the management of insomnia, and the target patient population includes adults with chronic insomnia disorder. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) system was used to grade the evidence and guide recommendations. The diagnostic procedure for insomnia, and its co-morbidities, should include a clinical interview consisting of a sleep history (sleep habits, sleep environment, work schedules, circadian factors), the use of sleep questionnaires and sleep diaries, questions about somatic and mental health, a physical examination and additional measures if indicated (i.e. blood tests, electrocardiogram, electroencephalogram; strong recommendation, moderate- to high-quality evidence). Polysomnography can be used to evaluate other sleep disorders if suspected (i.e. periodic limb movement disorder, sleep-related breathing disorders), in treatment-resistant insomnia, for professional at-risk populations and when substantial sleep state misperception is suspected (strong recommendation, high-quality evidence). Cognitive behavioural therapy for insomnia is recommended as the first-line treatment for chronic insomnia in adults of any age (strong recommendation, high-quality evidence). A pharmacological intervention can be offered if cognitive behavioural therapy for insomnia is not sufficiently effective or not available. Benzodiazepines, benzodiazepine receptor agonists and some antidepressants are effective in the short-term treatment of insomnia (≤4 weeks; weak recommendation, moderate-quality evidence). Antihistamines, antipsychotics, melatonin and phytotherapeutics are not recommended for insomnia treatment (strong to weak recommendations, low- to very-low-quality evidence). Light therapy and exercise need to be further evaluated to judge their usefulness in the treatment of insomnia (weak recommendation, low-quality evidence). Complementary and alternative treatments (e.g. homeopathy, acupuncture) are not recommended for insomnia treatment (weak recommendation, very-low-quality evidence).

Misperception of tiredness in young adults with insomnia.

People with insomnia often exhibit interpretive biases to cues associated with their condition. This study examined whether individuals with insomnia display an interpretive bias, such that they misperceive facial attributes of tiredness in a disorder-consistent manner. The efficacy of providing feedback related to the accuracy of participants' perception on later judgements of tiredness was further examined. Forty participants, 20 with DSM-5-defined insomnia disorder and 20 normal-sleepers, participated. The perception of one's own facial appearance of tiredness was assessed twice over two consecutive days using a visual task whereby participants indicated when a morphing image of their face represented their current level of tiredness. Visual and verbal feedback, related to participants' degree of misperception, was provided on completion of Day 1 testing. Overall, individuals with insomnia perceived their own face as significantly more tired than a baseline neutral photograph was, whereas normal-sleepers perceived themselves as appearing more alert. This pattern of results was only apparent on Day 1. Although no group × day interaction was established, mean scores suggest an improvement in perception on Day 2 amongst individuals with insomnia only. These findings suggest that individuals with insomnia exhibit a misperception of their facial attributes of tiredness, interpreting them in a disorder-consistent manner. This finding adds to the body of literature on cognitive models of insomnia, demonstrating more general cognitive biases in the disorder. Further, the results provide suggestive evidence that this misperception may be reformed.

People with insomnia: experiences with sedative hypnotics and risk perception.

BACKGROUND: Sedative hypnotics form an important part of managing insomnia and are recommended for short-term use. It is standard practice for clinicians to inform the patient to use medications only 'when required', but the use of these medications is often chronic. Little is known about the impact of standard labelling/instructions on promoting appropriate medication use for managing insomnia. OBJECTIVE: To explore patient medication-taking beliefs, experiences and behavioural practices relating to the use of pharmacological/complementary sleep aids for insomnia. SETTING AND PARTICIPANTS: Specialist sleep/psychology clinics and the general community in Sydney, Australia. METHOD: Semi-structured interviews were conducted with 51 people with insomnia using a schedule of questions to gauge their experiences, beliefs and current practices relating to insomnia medication use. Interviews were audio-recorded, transcribed verbatim and subjected to Framework Analysis to identify emergent themes. RESULTS: Participants held distinctive views about the safety and efficacy of complementary and pharmacological agents but do not intuitively turn to medications to resolve their sleep complaint. Medication use was affirmed through tangible medication-taking cues due to the ambivalence in current instructions and labelling. Practices such as dosage modification, medication substitution and delaying medication use might be important drivers for psychological dependence. CONCLUSION: Current labelling and instructions do not necessarily promote the quality use of sedative hypnotics due to the variability in patient interpretations. Clarifying the timing, quantity and frequency of medication administration as well as insomnia symptom recognition would play a significant role in optimizing the role of pharmacotherapy in the management of insomnia.

The role of perceived partner alliance on the efficacy of CBT-I: preliminary findings from the Partner Alliance in Insomnia Research Study (PAIRS).

Despite cognitive behavioral therapy for insomnia (CBT-I) being effective, barriers to adherence have been documented. Perceived partner alliance has been shown to influence adherence and treatment outcome across a range of other health conditions. The present study examined patients' perceptions regarding the role of their partner in CBT-I and the impact of perceived partner alliance on treatment outcome. Twenty-one patients were interviewed, following CBT-I, to examine the areas where partners were thought to influence the process of CBT-I. The majority of statements made during interviews explicitly mentioned a partner's influence (65%). Additionally, the production of more positive partner statements was associated with better treatment outcome (using the Insomnia Severity Index). The integration of perceived partner alliance into CBT-I is discussed.

An online behavioral self-help intervention rapidly improves acute insomnia severity and subjective mood during the coronavirus disease-2019 pandemic: a stratified randomized controlled trial.

STUDY OBJECTIVES: Stressful life events, such as the coronavirus disease-2019 (COVID-19) pandemic, can cause acute insomnia. Cognitive behavioral therapy for acute insomnia is effective but is both time and resource-intensive. This study investigated if an online behavioral self-help intervention, which has been successfully used alongside sleep restriction for acute insomnia, reduced insomnia severity and improved mood in acute insomnia. This study also assessed good sleepers to explore if a "sleep vaccination" approach was feasible. METHODS: In this online stratified randomized controlled trial, 344 participants (103 good sleepers and 241 participants with DSM-5 acute insomnia) were randomized to receive the intervention/no intervention (good sleepers) or intervention/intervention after 28 days (poor sleepers). Insomnia severity was assessed using the ISI (primary outcome), and anxiety and depression using the GAD-7/PHQ-9 (secondary outcomes) at baseline, 1 week, 1 month, and 3-month follow-up. RESULTS: In people with acute insomnia, relative to baseline, there were significant reductions in ISI (dz = 1.17), GAD-7 (dz = 0.70), and PHQ-9 (dz = 0.60) scores at 1-week follow-up. ISI, GAD-7, and PHQ-9 scores were significantly lower at all follow-up time points, relative to baseline. Subjective diary-derived sleep continuity was unaffected. No beneficial effects on sleep or mood were observed in good sleepers. CONCLUSIONS: An online behavioral self-help intervention rapidly reduces acute insomnia severity (within 1 week), and benefits mood in people with acute insomnia. These beneficial effects are maintained up to 3 months later. Although the use of the intervention is feasible in good sleepers, their subjective sleep was unaffected. CLINICAL TRIAL REGISTRATION: Testing an early online intervention for the treatment of disturbed sleep during the COVID-19 pandemic; prospectively registered at ISRCTN on 8 April 2020 (identifier: ISRCTN43900695).

Sleep-related attentional bias in poor versus good sleepers is independent of affective valence.

Contradictory evidence exists relating to the presence of an attention bias to sleep-related stimuli in poor sleepers/insomnia using the emotional Stroop task (EST). These inconsistencies may be due to methodological issues related to the affective valence of the sleep-related stimuli. Thus, individuals may attend differentially to sleep-related stimuli not because of their 'sleep' properties, but their negativity. The current study addresses this by controlling the affective valence of sleep-related words. A total of 107 participants [mean age = 33.22 years, standard deviation (SD) = 12.31 years; 61.7% female] were recruited during an evening event at the Newcastle Science Festival. Participants completed the Pittsburgh Sleep Quality Index (PSQI) and a computerized EST containing 20 non-affective sleep-related, 20 neutral and 20 negatively valenced threat words. Good and poor sleepers were categorized using the PSQI. There were no significant differences between groups on response latency to sleep-related words (t(105) = -0.30, P = 0.76). However, the interaction between good versus poor sleepers and word-type on response latency was significant (F(2,210) = 3.06, P < 0.05). Poor sleepers took longer to respond to sleep-related words (mean = 723.35, SD = 172.55) compared to threat words (mean = 694.63, SD = 162.17) than good sleepers (mean = 713.20, SD = 166.32; and mean = 716.65, SD = 181.14). The results demonstrate the presence of an attention bias towards sleep-related stimuli compared to threat stimuli in poor sleepers. Accordingly, poor sleepers may be consumed by stimuli relevant to their specific difficulties, as well as being more highly attuned to negative cues that signal anxious states. Thus, the present research suggests that there are two opposing forces at play: one which facilitates performance (non-specific threats) and one which hinders performance (personally relevant threats).

Biased processing of sleep-related stimuli in children of parents with insomnia.

Disorder-specific cognitive biases have been observed in children whose parents suffer from psychological disorders. Despite those same biases being observed in individuals with insomnia, they have yet to be explored as an index of vulnerability in children of parents with insomnia. It was hypothesized that potentially vulnerable children would demonstrate cognitive biases to sleep-related cues, relative to controls. Following a "tired-state induction," a sleep-related Emotional Stroop was completed by 2 groups: 38 children of parents with insomnia and 51 controls. Children also reported their observations about the content of the Stroop words. Results showed an attention bias in children whose parents have insomnia, but no interpretive bias. The results are discussed in terms of a predispositional vulnerability to insomnia.

The Role of Sleep Effort as a Mediator Between Anxiety and Depression.

Depression, anxiety, and insomnia are all conditions that share a complex bidirectional relationship. Sleep effort is a construct with cognitive and behavioral components that perpetuates insomnia. Although many studies have examined the associations between these three variables, no studies have yet examined sleep effort as a mediating variable between anxiety and depression and vice versa. Online versions of the Hospital Anxiety and Depression Scale and the Glasgow Sleep Effort Scale were administered to a sample of 1927 higher education students aged 18-40 years (75.9% women and 76% from 18 to 23 years old). As part of the survey, participants also completed a sociodemographic questionnaire. Mediation analysis indicated that sleep effort mediates the relationship between depression and anxiety, when the former was the predictor and the latter was the criterion. Moreover, sleep effort also mediated the relationship between anxiety and depression when the former was the predictor and the latter was the criterion, albeit in a lesser extent. Sleep effort appears to play a bidirectional mediational role between depression and anxiety, being a potential target for intervention.

To what extent is circadian phase predictive of subjective jet lag in long-haul cabin crew pre- and post-trip?

Long-haul cabin crew regularly report misalignment between their circadian phase and the external world (i.e. jet lag). The extent to which changes in circadian phase relate to reported levels of jet lag remains unclear. The main aim of the present study was first to evaluate the relationship between objective (circadian phase) and subjective jet lag and second to explore the relative role of both subjective and objective psycho-behavioural factors in predicting the subjective experience of jet lag. Twenty-eight long-haul cabin crew completed questionnaires measuring diurnal preference, trip characteristics and subjective jet lag as a single and as a multidimensional measure. Sleep was monitored using actigraphy and urinary melatonin peak time was measured, at baseline (T1), e.g. before a long-haul trip and post-trip on the crew's first recovery day (T2). Subjective jet lag was also measured at both time points. At T1, later circadian phase related to increased unidimensional jet lag, however, a post-trip discrepancy was found between objective and subjective uni- and multidimensional jet lag measured at T2 and change from T1 to T2. After controlling for direction and size of circadian phase, increased uni- and multidimensional subjective jet lag was predicted by depressed mood states. The regression models including phase, diurnal preference, departure time on the outbound sector and arousal levels accounted for 28% of the variance in unidimensional jet lag and 53% of the variance in multidimensional jet lag. It was concluded that there is a discordance between objective and subjective jet lag post-trip. Further, subjective jet lag in long-haul cabin crew is better explained by mood impairment than circadian phase. The results are discussed with reference to the gap between subjective and objective jet lag and the role of psychology rather than just biology in the jet lag experience. The implications for improving health and safety in the workplace, through a better understanding of the role of human factors in the management of jet lag, are discussed.