Behavioural insomnia and circadian rhythm disorders — formative SAQs

SAQ 1 — The toddler who wakes all night (20 marks, ~15 minutes)

A 15-month-old girl wakes three or four times every night and can only be resettled by being picked up and rocked, which she was rocked to sleep at bedtime. Her parents are exhausted. She is thriving, does not snore, and sleeps well once she is finally asleep. [1]

Questions

1. Give the most likely diagnosis and subtype, and the features that support it. (5 marks) [1]
2. Explain the mechanism that produces the repeated night wakings. (5 marks) [1]
3. State the first-line treatment and name two specific behavioural techniques you would use. (6 marks) [1] [2]
4. State the evidence that behavioural treatment works and what you would tell the parents to expect. (4 marks) [3]

Model answer (must-hit)

1. The most likely diagnosis is behavioural insomnia of childhood, sleep-onset association type. It is supported by the requirement to be rocked to fall asleep, the repeated night wakings that need the same rocking to resettle, normal sleep once asleep, normal growth, and the absence of snoring or other organic features. [1]
2. Every child has brief arousals throughout normal sleep. This child has learned that sleep begins only while being rocked, so at each normal arousal she cannot bridge back to sleep without that same condition being recreated, and she signals for a parent instead. The wakings are therefore a conditioned association, not a new problem each night. [1]
3. The first-line treatment is behavioural, not medication. I would use graduated extinction (controlled comforting, checking at gradually lengthening intervals so she learns to self-settle) and bedtime fading with a consistent, soothing bedtime routine, teaching her to fall asleep independently at the start of the night so she can resettle unaided later. [1] [2]
4. Mindell and colleagues' review, the American Academy of Sleep Medicine practice parameter and Meltzer and Mindell's meta-analysis show behavioural interventions are effective and durable for bedtime problems and night wakings, with benefit to the child and to parental wellbeing. I would warn parents that a brief increase in protest is common before improvement and that consistency is the key to success. [3]

SAQ 2 — The teenager who cannot wake for school (20 marks, ~15 minutes)

A 15-year-old boy cannot fall asleep before 2am despite trying, cannot be woken for school, and is missing classes. At weekends he sleeps from 2am to 11am and wakes refreshed. His mother wonders if he is depressed or just lazy. [8]

Questions

1. Give the most likely diagnosis and the features that support it. (5 marks) [8]
2. Explain why this is a biological problem in adolescence, not laziness. (5 marks) [9]
3. Outline your assessment, including one thing you must actively screen for. (4 marks) [8]
4. State your management, including how melatonin should be timed and why. (6 marks) [8] [6]

Model answer (must-hit)

1. The most likely diagnosis is delayed sleep-wake phase disorder. Supporting features are the stable inability to fall asleep until the early hours despite trying, the great difficulty waking for school, and — crucially — normal, refreshing sleep of normal length when he is allowed to sleep on his own late schedule at weekends. [8]
2. Adolescence brings a biological delay of the circadian clock and a slower build-up of homeostatic sleep pressure, so the teenager is genuinely not sleepy at the conventional bedtime. Evening light, screens, caffeine and early school start times worsen this "perfect storm". The late clock is biologically driven, which is why simply telling him to go to bed earlier fails. [9]
3. I would take a sleep history and a one to two week sleep diary (with actigraphy if available) to document the delayed phase, confirm adequate sleep opportunity, and exclude organic disorders. I must actively screen for depression, anxiety and suicidal ideation, because delayed phase presenting as school refusal frequently coexists with mood disorder. [8]
4. Management combines a fixed, realistic daily wake time, good sleep hygiene with reduced evening light and screens, timed morning bright light to advance the clock, and low-dose melatonin. The melatonin must be given several hours before his habitual sleep onset so it acts as a chronobiotic to shift the clock earlier, not as a large bedtime hypnotic. Chronotherapy and specialist referral are reserved for refractory cases, and school liaison supports attendance. [8] [6]