Circadian Rhythm Disorder

Overview

Circadian rhythm is an endogenous human physiological process responsible for the regulation of sleep. The process fluctuates over a period of 24 hours, but the pattern is usually repeated the same each day and is regularly updated by environmental stimuli such as light, so the body stays synchronised to its external environment.

Issues with either the endogenous time clock (intrinsic), or the external entrainment, (extrinsic) can lead to circadian rhythm sleep disorders.

Intrinsic causes

1. Delayed sleep phase disorder – falling asleep and waking more than 2 hours later than conventional and intended times. Individuals, for example, lie in bed unable to sleep until 3am, then wake naturally at 1pm. This is the most common circadian rhythm disorder seen in sleep clinics and causes secondary sleep deprivation if people need to set alarm clocks to interrupt sleep after an insufficient time in order to fulfil daytime commitments.
2. Advanced sleep phase disorder – often falling asleep more than 2 hours earlier than conventional times for example, sleeping at 6pm then waking at 4am. Excessive evening sleepiness is the most significant problem associated with this.
3. Irregular sleep wake rhythm disorder – An undefined sleep-wake cycle. Symptoms include extremely fragmented nocturnal sleep, with excessive daytime sleepiness and frequent napping. This is commonly seen in neurological conditions such as dementia and traumatic brain injuries and can be challenging for caregivers.
4. Non-24 hour sleep wake disorder – when the suprachiasmatic nucleus responsible for controlling circadian rhythm fails to entrain (synchronise) to a 24 hour day. Sleep length and wake length are regular, but the internal circadian rhythm is longer than 24 hours, so each day the sleep-wake cycle becomes delayed by at least 2 hours, resulting in periodic day-night reversal. This is seen most commonly in blind people.

Extrinsic causes

1. Shift work disorder
2. Jet-lag

Who to Refer

There are no specific criteria to be met for referral besides a reasonable suspicion of the disorder based on the description, above, and that the condition still interferes with daily function and doesn’t resolve following general advice (sleep hygiene and self help) and management in primary care. See treatment in primary care section below.

Adult patients (aged 18 years and over) can be referred as detailed in the Services section below.

Paediatric patients (aged under 18 years) -please consider the following service for advice: The neuropsychiatry team have established a drop-in consultation service for all local and community colleagues that occurs on the 1st Tuesday of each month at 15:00 p.m. They are happy to discuss patients aged under 18 who are being considered for referral in this forum. If a clinician would like to attend the drop in to discuss a patient then they can contact the team on 01173428168 or email them at paediatric.neuropsy@uhbw.nhs.uk

Treatment in primary care

Self-help

A patient information leafet may help patients to manage their condition.

Treatment consists of re-synchronising sleep and wake periods by medications and external stimuli.

Hypnotics – There is no evidence base to support their use in circadian rhythm disorder, though they may be used to treat co-existing insomnia. There is evidence against their use in elderly patients with dementia due to the adverse effects.

Light therapy - outdoor light, or bright light (2500 lumens and above from a SAD (Seasonal Affective Disorder) lamp can be exposed to a patient, for around 90 minutes at intended times of wakefulness (90 minutes or more in the first 3 hours after the intended waking time in delayed sleep wake phase), or in the period of daytime somnolence for advanced or irregular sleep wake phase disorder. There is weak evidence supporting this for Advanced and Irregular sleep wake phase disorder, and as a combination therapy with evening use of melatonin for delayed sleep wake phase disorder.  Typical treatment trials are for a one month period, but patients can utilise this until the circadian clock is synchronised with a conventional schedule, or continuously if they find it helpful in the

Chronotherapy – consists of delaying an individual’s bedtime until their sleep-wake cycle coincides with a conventional 24 hour day. There is inadequate evidence supporting sleep-wake scheduling in patients with circadian rhythm disorder, but it is a rational approach with low risk.

Melatonin - Melatonin is restricted as per BNSSG Formulary, please see formulary page for further details and should not currently be initiated in primary care. Restrictions also apply to prescribing in secondary care and therefore patients should be advised that a referral will not necessarily lead to a prescription.

Services

• Neuropsychiatry Sleep Disorders clinic - NBT

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