Insomnia


Disease modifying treatment available:
Time critical diagnosis and management:
Lateralising:


Definition

Difficulty initiating or maintaining sleep.




Aetiology

None

Disorder Clinical features Associated features Investigations Disease modifying treatment available Time critical
Depression Epilepsy
Obstructive sleep apnoea Cognitive impairment
Bilateral papilloedema
Anti-CASPR2 encephalitis Myokymia
Seizure
Generalised pain
Weight loss
Cerebellar ataxia
Hyperhidrosis
Psychosis
Amnesia
Thymoma
Anti-LGI1 encephalitis
Nocturia
Restless leg syndrome
Familial fatal insomnia

Causative drugs








Associated Disorders





Clinical features


Insomnia is associated with an increased risk of depression anxiety and substance abuse.

Insomnia should be differentiated from circadian rhythm disorders.

Insomnia may cause the following:





Investigations


None

None


Laboratory Investigation Result

Treatment


The management of insomnia can be considered in several steps:
1) Identification and treatment of any underlying cause
2) Encouraging good sleep hygiene
3) Regular exercise (but not late at night)
4) Medications

CBT is the most cost-effective treatment for chronic insomnia.

Medications to treat insomnia are primarily GABA A receptor agonists. Stimulation of these receptors produces a sedative effect. Additional effects include muscle relaxation, anti-epileptic effects, anxiolytics, memory impairment, behavioural disturbance and ataxia. If the half life of these medications is too long a 'hangover' effect with impaired function upon waking is observed. If the half life is too short rebound insomnia can develop. These drugs have significant potential for physiological dependence and a street value. Z-drugs targeting a specific GABAA receptor subtype are better tolerated. These medications have no role in the management of chronic insomnia.

Long acting melatonin is available for the treatment of insomnia in adults over the age of 55. A dual orexin receptor antagonist (daridorexant) are now also available.

Anti-depressant medications are sometimes used to help treat co-existent depression. The evidence basis for this is not great and all are used off license in the UK. The most commonly used anti-depressants for this purpose are trazodone, doxepin and mirtazapine.





Research


Open questions

None