Module 5 - Disorders of Sleep/Wake Cycles Flashcards
What is the modern definition of insomnia?
A perceived difficulty with sleep initiation, maintenance, consolidation, duration, or quality despite adequate opportunity, causing daytime impairment at least 3x/week for at least 3 months (ISCD-3).
How does the modern definition of insomnia differ from the literal Latin meaning?
The Latin root means ‘complete absence of sleep’ but insomnia today refers to reduced sleep due to inability to obtain desired sleep.
What circadian disorders can mimic insomnia?
Delayed sleep phase syndrome (trouble falling asleep) and advanced sleep phase syndrome (early morning waking).
How can sleep-disordered breathing be mistaken for insomnia?
Frequent arousals due to apnoea may be interpreted as insomnia despite the person being asleep.
What is the estimated worldwide prevalence of transient insomnia?
30–35%, with a median duration of 3 years and 56–74% having persistent symptoms after 1 year.
What are the three stages of insomnia and their contributing factors?
Predisposing (e.g., family history), precipitating (e.g., stress), and perpetuating (e.g., staying in bed longer, worry).
How does thought and emotional response influence insomnia?
Hyperarousal, worry, and emotional overreaction can maintain insomnia even if sleep is occurring.
What is the difference between fatigue and sleepiness?
Fatigue is exhaustion without sleep drive; sleepiness involves a strong tendency to fall asleep.
What are the PSG findings often associated with insomnia?
Longer sleep onset latency (SOL), reduced total sleep time (TST), increased awakenings, and reduced sleep efficiency.
How does insomnia relate to depression?
Insomnia can precede, predict, or contribute to depression. Treating insomnia improves depression outcomes.
What did the HUNT study find about insomnia and depression risk?
Untreated insomnia predicted depression with an OR of 6.1; depression predicted later insomnia with an OR of 5.
How is insomnia linked to anxiety?
Insomnia is common with anxiety, which is associated with nonrestorative sleep and increased nocturnal arousal.
What hormonal markers are elevated in insomnia?
Cortisol and ACTH are elevated, suggesting heightened physiological arousal.
What behavioural strategies help manage insomnia?
Same wake time, light exposure, wind-down routines, avoiding stimulating activities and substances before bed.
How do caffeine, alcohol, and food influence sleep?
Caffeine delays sleep; alcohol disrupts second-half sleep; large or protein-heavy meals can impair sleep.
What is stimulus control therapy (QHR)?
If not asleep in 15 mins, get out of bed. Return only when drowsy. Avoid stimulation while out of bed.
What is paradoxical intention therapy?
Trying to stay awake rather than fall asleep, reducing performance anxiety about sleep.
What is bed restriction therapy and how is sleep efficiency calculated?
Limit time in bed to match sleep time (minimum 5 hrs). Sleep efficiency = time asleep / time in bed * 100.
What is sleep misperception?
Underestimation of total sleep time; difficulty distinguishing light sleep from wakefulness.
What are key diagnostic criteria for insomnia (DSM-5 and ICSD-3)?
Difficulty initiating/maintaining sleep or early waking, 3x/week for ≥3 months, with daytime impact and adequate opportunity.
What are common subjective features of insomnia?
A persistent difficulty in falling asleep, staying asleep, early waking, or nonrestorative sleep despite adequate opportunity, often lasting ≥30 minutes.
What are typical PSG findings in insomnia?
Longer sleep onset latency, reduced total sleep time, more awakenings, reduced sleep efficiency, increased stage 1 sleep.
How does insomnia affect subjective vs. objective performance?
Objectively may perform similarly, but subjectively feel worse; more mental effort required.
What did Altena et al. (2008) find in elderly insomniacs?
They performed better on simple reaction time but worse on vigilance; cognitive behavioural therapy (CBT) reversed these effects.
What is the relationship between fatigue and sleepiness?
Fatigue is exhaustion without sleep drive; sleepiness is a drive to sleep. Sleepy insomniacs should be evaluated for OSA, depression, or circadian disorders.
What EEG changes occur during sleep in insomniacs?
Hyperactive amygdala firing during sleep; less frontal cortex activation in SWS; emotional responses may be exaggerated.
How was insomnia historically viewed in relation to depression?
Previously seen as just a symptom; now known to be a predictive and treatable factor for depression onset and recurrence.
What did the HUNT study show about insomnia and depression?
Untreated insomnia increased risk of future depression (OR 6.1); prior depression increased risk of future insomnia (OR 5).
How does anxiety contribute to insomnia?
Leads to nonrestorative sleep, increased nocturnal arousal, and sleep anxiety. Most frequently associated mental disorder.
What are PSG changes seen in anxious insomniacs?
Increased stage 2 sleep, increased awakenings, reduced TST and sleep efficiency, minor REM reduction.
What hormonal and neuroimaging findings support hyperarousal in insomnia?
Elevated cortisol and ACTH; functional imaging shows persistent alertness suggesting incomplete flip-flop switch deactivation.
What cognitive factors maintain chronic insomnia?
Worry about sleep, hypervigilance, distorted sleep perception, and unhelpful beliefs about sleep needs or consequences.
How does CBT for insomnia address behaviour and cognition?
Targets unhelpful behaviours first, then thinking patterns, then mood; behaviour improves quickly, cognition catches up over time.
What are examples of unhelpful pre-bed behaviours?
Exercise, stimulating conversations, screen use, caffeine, nicotine, alcohol, large or protein-rich meals before bed.
How does caffeine affect sleep?
Delays sleep onset and disrupts sleep quality; takes up to 8 hours to be cleared from the body.
What are the effects of alcohol on sleep?
Helps with sleep onset initially, but disrupts second half of sleep with more REM and lighter sleep; also dehydrating.
How can food before bed impact sleep?
Large meals cause discomfort and circadian disruption; proteins increase alertness. A small snack is best if hungry before bed.
What is the “stages of change” model in insomnia treatment?
Recognises readiness for change varies; interventions should be matched to current stage (e.g., precontemplation, contemplation, action).
What is actigraphy and how is it used in insomnia assessment?
Actigraphy involves using wrist-worn accelerometers to estimate sleep-wake patterns. It is especially useful in populations who can’t complete sleep diaries or self-report, like children or cognitively impaired individuals.
How does actigraphy compare with PSG in assessing insomnia?
Actigraphy is less accurate in detecting sleep stages but provides reliable long-term behavioral data. It doesn’t assess sleep architecture.
What are limitations of actigraphy?
Different scoring algorithms across devices, lower accuracy with more nighttime wakefulness, and inability to assess sleep architecture.
How are consumer sleep devices used in insomnia?
They track sleep via wearables (e.g., Fitbit, Oura) or nonwearables (e.g., Beddit), offering convenience but limited clinical accuracy.
What are the limitations of consumer sleep trackers in clinical use?
Poor validation, small studies, and limited reliability. They may provoke anxiety and are not a substitute for PSG or FDA-approved actigraphy.
How does clinical setting impact insomnia assessment?
Primary care may focus on quick diagnosis and medication, while sleep clinics offer comprehensive evaluation with possible PSG.
What is the value of interdisciplinary insomnia care?
Combines physical and psychological expertise — physicians assess medical contributors, while psychologists explore cognitive-behavioural factors.
How can bed partner input aid in insomnia assessment?
They can report on symptom frequency, severity, and screen for SRBD, PLMD, or parasomnias.
Which populations are at greater risk for insomnia?
Women (especially pregnant), older adults, people with lower income, those unemployed or with disability, and certain ethnic groups.
What are objective short sleep duration phenotypes in insomnia?
Patients with objectively short sleep (via PSG/actigraphy) may have greater physiological arousal, comorbidities, and worse prognosis.
How might wearable EEGs support future insomnia research?
They allow multi-night home monitoring, aiding phenotype identification and personalised treatment planning.
What are examples of insomnia phenotypes from data-driven clustering?
High subjective wakefulness, mild insomnia, insomnia-related distress, highly distressed, reward-sensitive, and high/low reactivity groups.
What is the prevalence of chronic insomnia in Australia?
12.2% (DSM-5) and 14.8% (ICSD-3), with only 7.5% formally diagnosed — highlighting underdiagnosis.
Which factors are linked to insomnia prevalence in Australia?
Higher in rural areas, English-speaking households, lower income, those with disability, and unemployed individuals.
How often do Australians seek help for insomnia?
Only 30% discussed sleep with a provider in the past year; even among those with chronic insomnia, under 50% sought help.
What treatments are underutilised for insomnia in Australia?
Only 8.7% use CBTi regularly. Medications used more often but still low (e.g., 12.3% use prescribed meds ≥3 nights/week).
What does ‘circadian’ mean?
Processes with an approximately 24-hour period.
What is the intrinsic human circadian period (tau)?
About 24.2 hours.
What structure serves as the master circadian pacemaker?
The suprachiasmatic nucleus (SCN) in the anterior hypothalamus.
What is the role of the SCN in alertness?
Produces an alerting signal during the day and reduces it at night to promote sleep.
What are zeitgebers and what is the most potent one?
Zeitgebers are external time cues that entrain the circadian rhythm; light is the most potent.
What photoreceptors communicate light to the SCN?
Melanopsin-containing retinal ganglion cells via the retinohypothalamic tract.
What is the primary neurotransmitter in the RHT?
Glutamate.
What other neurotransmitter is co-released in the RHT?
Pituitary adenyl cyclase-activating peptide (PACAP).
What thalamic structure relays non-light zeitgebers to the SCN?
The intergeniculate leaflet (IGL).
When is melatonin secreted?
During the dark cycle, beginning 2–3 hours before habitual bedtime.
What inhibits melatonin secretion?
Light exposure, via SCN inhibition of PVH neurons.
What neurotransmitter stimulates the pineal gland to secrete melatonin?
Norepinephrine, acting via beta-1 receptors.
What enzyme catalyzes the rate-limiting step in melatonin synthesis?
Arylalkylamine N-acetyltransferase (AA-NAT).
What is the half-life of melatonin?
About 30–45 minutes.
What effect does melatonin binding MT1 receptors have?
Decreases the SCN alerting signal (hypnotic effect).
What effect does melatonin binding MT2 receptors have?
Shifts the circadian phase.
What is the dim light melatonin onset (DLMO)?
The time melatonin surpasses a threshold (~3 pg/mL saliva), about 2–3 hours before habitual bedtime.
What are the two main processes in the two-process model of sleep?
Homeostatic sleep drive (Process S) and circadian alerting signal (Process C).
What is CBTmin and when does it occur?
Minimum core body temperature, ~2 hours before spontaneous wake time.
What is the relationship between DLMO and CBTmin?
CBTmin occurs ~7 hours after DLMO.
When does light exposure cause a phase advance?
When given after CBTmin.
When does light exposure cause a phase delay?
When given before CBTmin.
What type of light has the greatest effect on circadian phase?
Short wavelength (blue light, ~460 nm).
How much light is required for circadian phase shifting?
Depends on prior exposure, timing, and intensity — natural outdoor light is most effective.
What is a phase response curve (PRC)?
A graph that describes the direction and magnitude of circadian phase shifts in response to stimuli (e.g., light, melatonin) depending on timing.
What does light do when administered before CBTmin?
It causes a phase delay.
What does light do when administered after CBTmin?
It causes a phase advance.
What is the PRC for melatonin?
Melatonin causes phase advances when taken in the afternoon/early evening and delays when taken in the morning.
How is melatonin used in circadian rhythm disorders?
It can be used as a chronobiotic to shift the timing of the circadian rhythm or as a hypnotic to aid sleep onset.
What dose of melatonin is typically used for phase shifting?
Low doses (e.g., 0.3–1 mg), taken 5–6 hours before habitual bedtime.
What dose of melatonin is typically used for sleep initiation?
Higher doses (e.g., 2–5 mg), taken closer to bedtime.
How should melatonin be timed in DSWPD?
2–3 hours before habitual bedtime to advance sleep onset.
Which gene mutations are associated with familial advanced sleep phase disorder (FASPD)?
PER2 and CSNK1D mutations.
Which gene mutation is associated with familial delayed sleep phase disorder (DSPD)?
CRY1 mutation.
What are the diagnostic criteria for DSWPD?
Significant delay in sleep onset and wake time relative to desired times, with preserved sleep duration and quality.
How is DSWPD managed?
Chronotherapy (gradually delaying sleep), light therapy in the morning, melatonin in the evening, consistent scheduling.
What is non-24-hour sleep-wake rhythm disorder (N24)?
A circadian disorder where the sleep-wake cycle is longer than 24 hours, often seen in totally blind individuals.
How is N24 treated?
Melatonin or tasimelteon (a melatonin receptor agonist), timed light exposure in sighted individuals.
What is irregular sleep-wake rhythm disorder (ISWRD)?
Characterised by fragmented sleep across 24 hours with no consistent sleep or wake pattern.
What causes ISWRD?
Common in neurodegenerative disease, brain injury, or lack of social/environmental time cues.
What are treatment strategies for ISWRD?
Structured routines, scheduled light exposure, melatonin, behavioural intervention.
How does N24SWRD differ between blind and sighted individuals?
Blind individuals typically have normal tau and fail to entrain due to lack of light; sighted individuals often have long tau and poor light entrainment.
What is the typical tau in sighted individuals with N24SWRD?
Usually 24.5 to 25.5 hours, but can be as long as 26.5 hours.
How does melatonin dosing affect entrainment in N24SWRD?
Lower doses (0.5 mg) may be more effective than high doses (e.g., 10 mg) in some patients.
What is tasimelteon and its role in N24SWRD?
A melatonin agonist (Hetlioz) approved for N24SWRD; dose: 20 mg 1 hour before bedtime. More selective for MT2 receptors.
What are tasimelteon side effects?
Headache, vivid dreams, ALT elevation, respiratory/urinary infections. Not to be taken with CYP1A2 inhibitors.
How is N24SWRD treated in sighted individuals?
Timed melatonin (0.5–4 mg) and morning light exposure. Treatment is difficult and long-term adherence is low.
What neural pathway transmits circadian signals from the SCN?
SCN → vSPZ → DMH, which regulates sleep propensity, temperature, and cortisol.
What is required for diagnosing N24SWRD according to ICSD-3?
At least 14 days of sleep logs documenting a free-running rhythm.
What is the most reliable circadian phase marker in N24SWRD?
Melatonin midpoint (DLMO), due to societal influences on sleep times.
What are key features of advanced sleep-wake phase disorder (ASWPD)?
Early sleep onset and awakening, more common in elderly, worsened by early morning light.
How is ASWPD treated?
Evening light exposure, avoiding naps, possibly avoiding early morning walks.
What defines irregular sleep-wake rhythm disorder (ISWRD)?
≥3 sleep episodes scattered across 24 hours, often with neurodegenerative disorders.
How is ISWRD treated?
Daytime light, structured routines, quiet/dark nights. Melatonin in children with neuro conditions. Avoid hypnotics.
What is shift work disorder (SWD)?
Daytime sleep difficulty and impaired alertness at night due to work schedule misalignment.
How is SWD treated?
Pre-shift nap, light at shift start, caffeine or modafinil, dark glasses for drive home, melatonin before day sleep.
What is jet lag and what causes it?
Circadian misalignment from travel across ≥2 time zones. Eastward travel requires harder phase advance; westward requires easier phase delay.
How is jet lag managed?
Light avoidance at wrong times, light exposure at correct times, melatonin before desired sleep, and allowing 1 day of adaptation per time zone.
What is lifestyle-driven hypersomnolence?
Hypersomnolence caused by social and lifestyle factors, not physiological issues, leading to insufficient sleep.
What are common causes of insufficient sleep?
Family responsibilities, studying, socialising, media use, and overcommitting daily tasks.
What percentage of Australians are not getting the sleep they need according to a 2019 parliamentary inquiry?
Four in ten Australians.
What causes jet lag?
Circadian misalignment due to crossing time zones; sleep and wake cycles are out of phase with local time.
Why is travelling west easier than travelling east?
Because it is easier to delay the circadian rhythm (sleep later) than to advance it (sleep earlier).
What strategies help reduce jet lag?
Gradual pre-adjustment of sleep before departure, adapting to local time slowly, avoiding critical tasks soon after arrival.
What is Shift Work Sleep Disorder (SWSD)?
A condition in shift workers involving difficulty adjusting to sleep-wake schedules, leading to fatigue, headaches, and cognitive issues.
What cognitive processes are impaired by shift work?
Vigilance, attention, decision making, psychomotor function, and affect regulation.
What are the two biological processes governing sleep?
Process S (homeostatic sleep pressure) and Process C (circadian rhythm for sleep propensity).
Why is night shift sleep often fragmented?
Circadian alerting signals increase at night, making it harder to fall asleep and stay asleep during the day.
What happens to alertness during night shifts?
Alertness declines as melatonin rises and the circadian alerting signal dissipates, impairing performance.
What percentage of the U.S. workforce works shifts outside the typical day shift?
Between 17.7% and 25.9%.
What are examples of shift types?
Early morning (4–7am), night (6pm–4am), evening (2–6pm), and rotating shifts.
Why are permanent night shifts common in North America?
They provide perceived stability and are often assigned to newer employees.
Which age group has more difficulty with shift work?
Older adults, due to reduced adaptability to circadian changes.
How much less sleep do shift workers typically get?
30–60 minutes less per day compared to day workers.
Which shift tends to allow longer sleep duration?
Evening shifts, due to alignment with circadian delay and dark hours.
What societal and family factors reduce shift worker sleep?
Parental duties, daytime obligations, and need to align with social norms.
What is the rate of clinically significant sleep disturbance in night shift workers?
18.5%, over twice that of day workers.
What is the estimated annual cost of insomnia-related work issues in the U.S.?
$15 to $17.7 billion.
How does shift work impact psychomotor vigilance?
Reduces reaction time, slows response, increases lapses — particularly at night.
What are ‘microsleeps’ and when are they most likely?
Brief intrusions of sleep into wakefulness, often lasting seconds; most common during circadian troughs.
How does shift work affect attention and decision-making?
Attention lapses increase; decision-making becomes slower, more error-prone, and impulsive.
What types of memory are affected by sleep loss?
Working memory, short-term recall, and long-term consolidation (especially of emotional and declarative memories).
What brain regions are most affected by sleep deprivation?
Prefrontal cortex (executive function), amygdala (emotional reactivity), and hippocampus (memory consolidation).
How does sleep deprivation affect emotional processing?
Increases amygdala reactivity and reduces regulation by prefrontal cortex, leading to emotional lability.
How is empathy affected by sleep loss?
Reduced ability to read others’ emotions, decreased emotional sensitivity and social responsiveness.
What real-world risks are associated with shift work and sleep loss?
Increased rates of workplace injuries, road accidents, medical errors, and public safety incidents.
What time of day are fatigue-related errors most likely?
Between 2–6am during the circadian nadir.
What was the role of fatigue in the Exxon Valdez disaster?
Crew fatigue was identified as a major contributing factor to the oil spill.
How does sleep deprivation affect safety in healthcare?
Increased prescribing errors, missed diagnoses, and reduced attention to patient cues.
What is the impact of night shift on learning and performance in students?
Impaired concentration, slower processing, lower academic performance, and less effective memory encoding.
How does fatigue impair complex task performance?
Reduces ability to multitask, maintain focus, and make accurate judgments under pressure.
How can strategic napping help shift workers?
Naps reduce sleep pressure and improve alertness; a 10–30 min nap can enhance performance without grogginess.
When is the best time to nap before a night shift?
1–2 hours before starting the shift to reduce sleepiness during the first half.
What is a ‘prophylactic nap’?
A nap taken before anticipated sleep deprivation to build resilience against fatigue.
How does caffeine help shift workers?
Improves alertness and performance, especially when used at the start of a night shift or mid-shift.
When should caffeine use be avoided during a shift?
In the second half of the shift to prevent interference with post-shift sleep.
What medications may be used to promote wakefulness in shift workers?
Modafinil and armodafinil (with caution); melatonin may aid daytime sleep but with modest effects.
How can light exposure improve circadian alignment?
Bright light at shift start promotes alertness and phase delay; avoiding light post-shift prevents undesired circadian shifting.
What are light hygiene strategies for shift workers?
Use bright light at night, wear blue-blocking glasses post-shift, keep sleep environment dark and quiet.
What is the best shift rotation schedule?
Clockwise (morning → evening → night), with at least 48 hours off between transitions.
Why is clockwise rotation preferred?
It aligns with the natural circadian delay tendency and is easier to adjust to.
What workplace strategies can reduce shift work fatigue?
Scheduled breaks, environmental lighting, fatigue education, reducing consecutive night shifts.
What role can employers play in managing shift work risk?
Implement fatigue risk management systems, offer health screening, and promote sleep-friendly culture.
What are policy-level recommendations for safer shift work?
Limit night shift duration, encourage rest breaks, regulate maximum work hours, and provide sleep education.
What is the most important consistent habit for circadian rhythm regulation?
Regular wake time — even on weekends, as morning light exposure anchors circadian rhythm.
Why is a regular lights-off time less important than a regular wake time?
The wake time anchors the circadian rhythm more effectively via light exposure.
How should your bedroom environment support sleep?
It should be cool, dark, quiet, and free of anxiety-provoking or distracting elements.
What should your bed be used for?
Only for sleep and sex — no screens, no other activities.
Why is limiting bed use to sleep helpful?
It reinforces the mental association between bed and sleep, improving sleep efficiency.
What is sleep efficiency and how is it calculated?
Percentage of time in bed spent asleep. E.g., 6h sleep/9h in bed = 67%; 6h sleep/7h in bed = 86%.
What should you do if you’re awake in bed for more than 15 minutes?
Get out of bed, do something non-stimulating, and return when sleepy.
What does it mean to ‘respect sleep’?
Allocate enough time to sleep, but don’t obsess over it. Pressure can worsen insomnia.
What are examples of effective wind-down cues?
Showering, brushing teeth, reading a boring book, using low light, doing low-cognitive activities.
Why avoid stressful tasks before bed?
They raise cortisol, which should peak in the morning and disrupt sleep onset.
Why should caffeine be avoided in the second half of the day?
It has a half-life of 5–6 hours; 150 mg at 3pm means ~75 mg still active by 9pm.
How does alcohol affect sleep?
May help with falling asleep, but disrupts second half of the night and suppresses REM.
What are practical tips when co-sleeping with a partner?
Agree on who handles child wakeups, discuss noise/light levels, address pets, phones, and blanket sharing.
What should you do about clock-watching?
Avoid it. If you’ve set an alarm, trust it. Clock-watching increases cognitive arousal.
Who is Randy Gardner and why is he significant in sleep research?
Randy Gardner stayed awake for 11 days (264 hours) in 1964 as part of a school science experiment, demonstrating the extreme cognitive and physiological effects of sleep deprivation.
What symptoms did Randy Gardner experience during his 11-day wakefulness?
Mood changes, memory issues, hallucinations, cognitive lapses, and microsleeps. He showed surprisingly fast recovery after sleep.
What did the Randy Gardner case teach us about sleep deprivation?
That while extreme sleep loss is survivable short-term, it causes profound cognitive and perceptual dysfunction, and recovery occurs but does not fully compensate hour-for-hour.
What was the outcome of the 2019 Australian Parliamentary Inquiry into Sleep?
It formally recognised sleep as a public health priority and called for increased awareness, though many recommendations have not yet been implemented.
What media example highlighted sleep awareness and public neglect?
The documentary ‘The Sleep Revolution’ emphasised society’s undervaluation of sleep despite known health risks.
What is jetlagrooster.com and how is it used?
An online tool that generates personalised jet lag management plans based on flight details and destination.
What kinds of apps or tools can help manage jet lag?
Apps that provide personalised light exposure and sleep timing schedules to help reduce jet lag (e.g., Timeshifter, Jet Lag Rooster).
How long did Randy Gardner stay awake and what were the effects?
264 hours (11 days); experienced extreme drowsiness, irritability, reduced stress tolerance, but no psychosis. Recovery sleep occurred over several days.
What did the Randy Gardner case demonstrate?
That prolonged sleep deprivation causes significant functional impairment but is not necessarily permanently damaging.
What were the findings of Kollar et al.’s 205-hour sleep deprivation study?
Participants showed impaired attention, reduced concentration, cognitive slowing, and personality changes on the MMPI.
How did Kollar et al.’s findings differ from Gardner’s?
Kollar’s participants were monitored in clinical settings and exhibited more profound and measurable cognitive changes.
What did the 1896 Patrick & Gilbert study show about sleep loss?
90 hours of sleep deprivation led to psychomotor slowing, sluggish thinking, and increased reaction times.
What did Legendre and Pièron observe in dogs after sleep deprivation?
Drowsiness, slowed responses, and physiological signs of accumulating sleep pressure.
What was observed in Kleitman’s puppy sleep deprivation study?
Puppies remained awake longer with social stimulation but eventually showed signs of fatigue and sleepiness.
What key principle was illustrated in the puppy sleep study?
Environmental stimulation can temporarily mask sleepiness, but homeostatic pressure builds and ultimately forces sleep.
What are the three pillars of good health for adolescents?
Good sleep, regular exercise, and good nutrition.
What is the most Googled personal health question?
‘Why am I always tired?’
Why are teens particularly vulnerable to sleep deprivation?
Because of a combination of late body clocks, academic and social pressures, screen use, and under-recognition of sleep needs.
What is the ‘perfect storm’ of factors that sabotage teen sleep?
Late body clocks, inflexible school start times, social media, part-time jobs, homework, hormones, stress, ambition, screen addiction, reduced parental control.
What percentage of teens are chronically sleep deprived on school days?
70% — more than triple any other age group.
Which countries are the most sleep-deprived according to data?
South Korea, the United States, and Australia (3rd worst globally).
What societal factor is closely linked to national sleep deprivation?
Rate and speed of adoption of new screen technology.
What are some physical and mental health consequences of teen sleep deprivation?
Poor academic performance, suicide risk, motor vehicle accidents, anxiety, depression, emotionality, drug use, impaired judgment, obesity, immune dysfunction.
What is the increase in suicide risk associated with just one hour of lost sleep?
58% increase in teen suicide risk.
How does sleep deprivation affect ethical decision-making in teens?
It impairs prefrontal cortex function, increasing emotional and risky decisions.
What is ‘conditioned insomnia’ in teens?
Inability to fall asleep due to training the brain to associate bed with stimulating activities, especially screen use.
What is the impact of screen use before bed on adolescent sleep?
Suppresses melatonin, increases arousal, delays sleep onset, and reduces sleep duration and quality.
What brain region is primarily affected by late-night screen use?
The prefrontal cortex, which is responsible for reasoning, judgment, and self-regulation.
What is meant by ‘cognitive shutdown’ in teens?
The process where the prefrontal cortex goes offline from lack of sleep, increasing emotional reactivity and impulsivity.
How long does it take for prefrontal function to fully return after a night of poor sleep?
At least 2–3 nights of sufficient recovery sleep.
Why is prefrontal cortex vulnerability a concern for teenagers?
It’s still developing and is especially susceptible to sleep deprivation and overstimulation.
How do early school start times affect adolescent sleep?
They reduce total sleep time, misalign with teen circadian rhythms, and increase daytime sleepiness.
What biological shift occurs in adolescence that affects sleep timing?
The circadian rhythm delays by about 1–2 hours, making it harder to fall asleep early.
What time should school ideally start to align with teen circadian biology?
Around 9:30am or later.
What are the benefits observed after delaying school start times?
Increased sleep duration, improved attendance, mood, academic performance, and reduced car accidents.
Why have some schools resisted later start times?
Concerns about sports schedules, transport logistics, parent work hours, and tradition.
What is social jetlag?
A misalignment between biological sleep rhythms and social obligations, especially when weekend sleep patterns differ significantly from weekdays.
How much of a sleep phase shift on weekends is considered harmful?
A shift of more than 1.5–2 hours can have negative effects on alertness, mood, and metabolic function.
Why is weekend oversleep not a good solution to weekday sleep loss?
It delays the circadian rhythm further, making Sunday night sleep onset harder and perpetuating the cycle.
What is the ‘Sunday night effect’?
Difficulty falling asleep on Sunday nights due to weekend sleep-ins and circadian phase delay.
How can parental behaviour impact teen sleep?
Setting limits on bedtimes and screens, modelling healthy routines, and enforcing consistent wake times can improve teen sleep.
Why is parental involvement in teen sleep declining?
Increased adolescent independence, busy family schedules, and lack of awareness about sleep importance.
What are common parental misconceptions about teen sleep?
Believing teens are lazy, underestimating sleep need, or assuming they can ‘catch up’ on weekends.
Why should adolescent sleep be framed as a public health issue?
Because it affects academic performance, mental health, driving safety, and long-term health outcomes.
What are effective strategies to improve teen sleep at a population level?
Later school start times, screen curfews, public education, and accessible behavioural sleep interventions.
What role do schools and communities play in improving teen sleep?
They can adjust timetables, educate students and parents, support sleep-positive policies, and foster sleep-friendly environments.
What is the two-process model of sleep regulation?
It includes Process S (homeostatic sleep pressure, which builds with wakefulness) and Process C (circadian rhythm, which governs optimal sleep timing).
How does sleep pressure change during adolescence?
It builds more slowly, making teens less sleepy at typical bedtimes.
What circadian changes occur in adolescence?
Melatonin secretion is delayed, leading to later sleep onset and preference for later bed and wake times.
How does light exposure impact melatonin and circadian alignment?
Evening light delays melatonin onset; morning light advances it but is less effective when sleep-deprived.
What are common red flags for adolescent sleep deprivation?
Difficulty waking for school, excessive weekend sleep-ins, frequent naps, and morning irritability.
Why are weekend sleep-ins counterproductive?
They delay the circadian rhythm and make Sunday night sleep onset harder, worsening weekday fatigue.
What does ‘cognitive shutdown’ refer to in tired teens?
The reduced function of the prefrontal cortex, impairing attention, memory, and decision-making.
Why does learning suffer after sleep deprivation?
New information may not be encoded effectively (‘in one ear, out the other’) and memory consolidation is impaired.
How many nights of good sleep are needed to consolidate learning?
At least two nights of sufficient sleep.
How did COVID-19 lockdowns affect teen sleep?
Teens slept more with flexible schedules and later wake times during remote learning.
What schooling model preserved sleep best during the pandemic?
Asynchronous online learning (vs. early start synchronous classes).
What is the SleepShack program?
An online CBT-based sleep intervention for teens including assessment, bedtime fading, light therapy, and behavioural strategies.
What are the steps included in the SleepShack intervention?
Online assessment, daily sleep log tracking, melatonin-safe wind-down routine, bedtime fading, bright morning light exposure, clinician support if needed.
How does SleepShack involve parents?
Parents receive automated alerts and can support environment management and routine enforcement.
What behavioural principles underlie SleepShack?
Stimulus control, sleep restriction (via bedtime fading), and circadian alignment via light exposure.
Why do some teens resist sleep recovery even when tired?
Low motivation, underestimation of fatigue impact, screen addiction, and reward system dysfunction.
How can families help improve adolescent sleep?
By promoting consistent wake times, limiting evening light exposure, using calm routines, and setting digital curfews.
What is a key communication principle when discussing sleep with teens?
Avoid judgment; focus on their goals (e.g., academic, sport performance) and link sleep to those outcomes.
Why is understanding adolescent reward systems important in sleep support?
Teens may prioritise immediate gratification (e.g., screen time) over long-term benefits, requiring goal-based motivation strategies.
What role do clinicians play when behavioural strategies alone aren’t enough?
Providing support for co-occurring anxiety, depression, or neurodevelopmental disorders interfering with sleep improvement.
What is slow-wave activity (SWA) and its relevance to adolescent sleep?
SWA reflects homeostatic sleep pressure and declines exponentially overnight. It’s used to gauge sleep need and recovery.
What is the role of the suprachiasmatic nucleus (SCN)?
It acts as the brain’s master clock, regulating circadian rhythms based on light input.
How do screens influence adolescent brain chemistry?
Active screen use triggers dopamine, adrenaline, and cortisol release, increasing arousal and making sleep onset harder.
What is ‘infomania’ in the context of adolescent sleep?
A state of constant anticipatory alertness due to notifications and messages, contributing to conditioned arousal and sleep disruption.
How did Australian education performance rank in recent PISA data?
Australia ranked 39th out of 41 developed nations in performance declines, partly attributed to student sleep deprivation.
How did late school start time reforms compare to education spending (Gonski 2.0)?
Delaying school start times produced better academic improvements than $28 billion in traditional education spending.
How does sleep interact with genetic risk for depression in teens?
Teens with genetic vulnerability only showed depressive symptoms during life transitions (e.g. starting uni) if they were also sleep-deprived.
What protective role does sleep play in adolescent mental health?
Sufficient sleep buffers teens from developing mood disorders, even if they have genetic susceptibility.
What are recommended guidelines for morning light therapy in teens?
Exposure to 2,500–10,000 lux of bright light in the morning helps shift circadian rhythms earlier.
Why combine melatonin with light therapy?
The combination is more effective for circadian realignment than using either intervention alone.
How does sleep timing differ between DSWPD and behavioural insomnia in teens?
DSWPD involves consistent delayed sleep onset (e.g., 2–6am), even without screens. Behavioural insomnia has variable timing linked to screen use or lack of routine.
How is sleep duration on weekends different in DSWPD vs. screen-related insomnia?
DSWPD teens sleep normally when allowed to follow their body clock. Behavioural insomnia teens may still have fragmented or insufficient sleep.
What is the weekly pattern of cognitive symptoms in DSWPD vs. behavioural insomnia?
DSWPD causes persistent sluggishness and sleepiness all week. Behavioural insomnia shows worse performance on weekdays with improvement on weekends.
What distinguishes sleep quality in DSWPD vs. screen-induced insomnia?
DSWPD teens sleep well once asleep. Behavioural insomnia often involves fragmented sleep and difficulty winding down.
How do weekends help differentiate the two disorders?
DSWPD teens continue late sleep patterns. Behavioural insomnia teens often improve with more parental control or less screen time.
What does DLMO testing reveal in DSWPD vs. behavioural insomnia?
DLMO is delayed in DSWPD but normal in behavioural insomnia.
What is the treatment response difference between DSWPD and screen-induced insomnia?
DSWPD requires structured light and melatonin therapy. Behavioural insomnia often improves rapidly with screen limits and routine.
How does motivation differ in DSWPD vs. behavioural insomnia?
DSWPD teens are often motivated but misaligned biologically. Behavioural insomnia teens may lack motivation and have low insight.
