Part 3 - Sleep Disorders

Insomnia def (2)

• Chronic difficulty initiating or maintaining sleep, or waking too early (only 1 of these required) or early waking

• Associated with at least one aspect of daytime impairment (fatigue, irritability, poor concentration)

Prevalence of insomnia? (1)

• Affects approx 10% of population

Spielman’s 3Ps Model of Insomnia Aetiology: what do the 3 Ps stand for?

1. Predisoposing: unchangeable things

2. Precipitating: circumstances

3. Perpetuating: behaviours which maintain insomnia

Predisposing factors w/ examples (3)

• Genetic

• Sex (female), age (older)

• Personality (high neuroticism/anxiety)

Precipitating factors example (1)

• Stressful life events (job, divorce, physical illness)

Perpetuating factors examples (2→2)

• Unhelpful behaviours

  • E.g. staying home bc too tired → less sleep pressure build up → more difficulty sleeping

• Unhelpful cognitions

  • Negative rumination + worry about consequences of lack of sleep → negative associations w/ bedroom environment → perpetuates cycle of insomnia

Treatment for insomnia: name, description

• CBTI (Cognitive Behavioral Therapy for Insomnia)

• Multicomponent: education, relaxation training, sleep-restriction therapy

Sleep restriction therapy description (1), why it works (2)

• Temporarily reduce time in bed to match time asleep → gradually increase over time

• Increases sleep pressure

• Breaks negative association between bed + not sleeping

Delayed sleep-wake phase disorder description (2)

• Circadian rhythm disorder

• Sleep period is shifted significantly later (usually about ~2 hours)

Symptoms of delayed sleep-wake phase disorder (2)

– Difficulty falling asleep and awakening at desired or required clock time.

– Improved sleep quality and quantity when allowed to sleep ad libitum

Aetiology of delayed sleep-wake phase disorder: 2 possibilities

• Body clock shifted 2 hours later

OR

• Slower circadian oscillator (i.e. longer circadian rhythm, 24.5 hrs instead of 24.2)

Delayed sleep-wake phase disorder treatment

Light therapy - using bright light therapy in the morning and dim light in the evening (gradually shifting lighting timing earlier) to gradually shift the circadian rhythm earlier

Narcolepsy description (1)

Characterised by "sleep attacks" where individuals drift into sleep (often directly into REM) throughout the day

Cataplexy: relationship to narcolepsy (1) + description (1)

• Can be symptom of narcolepsy

• Sudden loss of muscle tone triggered by strong emotions → individual collapses whilst still conscious

Narcolepsy aetiology

• Orexin is a neuropeptide which promotes wakefulness

• (90% of) orexin neurons/receptors degenerate → lack of wakefulness

Narcolepsy treatment (1) + note (1)

• Primarily prescription of stimulants (e.g. modafinil)

• There is hope synthetic drugs that stimulate orexin receptors will be developed

REM sleep behaviour disorder (RBD) description (1)

• Lack of muscle atonia (paralysis) during REM sleep, leading individuals to physically act out violent or vivid dreams

RBD aetiology + what it can be a precursor to (2)

• Neurodegeneration in the brain stem

• It is often a precursor to Parkinson’s disease or Lewy body dementia (indicates early neurodegeneration)

Clinical characteristics of RBD (2)

• Onset is usually after 50 years

• More common in men than women

RBD treatment (1)

• Usually involves anti-anxiety medications/anti-anxiolytics (e.g., clonazepam) or melatonin, though these can cause daytime sedation

Consequences of poor sleep (4, common sense)

• Mental Health: Robust links to depression, anxiety, and lower life satisfaction.

• Physical Health: Increased risk of obesity, cardiovascular disease, and chronic pain.

• Cognitive/Academic: Correlated with poorer grades and impaired attention, though evidence on broader cognitive functioning is mixed.

• Risk-Taking: Poor sleep in youth is linked to increased drug/alcohol use, risky sexual behavior, and "sleepy driving."

Complete lack of sleep (disorder): name, description + consequence

• Fatal Familial Insomnia (FFI)

• Genetic disease: complete inability to sleep → organ failure + death

Relationship between insomnia + mortality (2)

• Insomnia itself not associated with increased mortality risk

• But use of hypnotics (to treat insomnia), is