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Narcolepsy and Kleine-Levin syndrome

The Lifespan Sleep Disorder Group at Guy's and St Thomas' provides specialist services for children and adults with rare disorders characterised by excessive daytime sleepiness (often called hypersomnia).

Narcolepsy and Kleine Levin syndrome are two examples of disorders we see.

Children and young people with the conditions are cared for by a multidisciplinary team (a team made up of different healthcare professionals), with support groups, and school input.

At 16 they are then moved smoothly to adult services through special transitional clinics.

Please see our referrals page if you'd like to refer anyone with excessive daytime sleepiness.

More information

Narcolepsy and cataplexy

What is it?

This is a rare sleep disorder with irresistible and unpredictable daytime sleep attacks and a number of other symptoms.

Cataplexy, unique to narcolepsy, is a sudden episode of muscle weakness triggered by emotions.

Typically, the person’s knees buckle and may give way upon laughing, surprise or anger. In other typical cataplectic attacks the head may drop or the jaw may become slack.

Cataplexy in children is slightly different and a variety of symptoms and movements including tongue protrusion and involuntary arm movements have been described.

As these symptoms look similar to other neurological movement disorders, it's common to explore a range of other conditions before the diagnosis of narcolepsy with cataplexy becomes more certain.

Clinical services

We're a busy service, running clinics for over 120 children with narcolepsy and cataplexy.

We share care with local services, and then transition these young people at 16 years to our adult sleep services.


We have extensive diagnostic equipment and tests, including inpatient polysomnography and multiple sleep latency testing, as well as HLA and hypocretin measures.


After accurately diagnosing the condition, we work with parents and schools to increase an understanding about narcolepsy and its symptoms.

This becomes crucial around exam times when our specialist sleep psychology service liaises with schools, to provide tailored information

Support groups

Narcolepsy is rare and many children and families might feel they are on their own.

Our peer support groups are popular events where around 10 children and families in particular age bands come together to ask questions, problem solve, and meet others experiencing the same challenges.

Kleine Levin syndrome (KLS)

This is a very rare sleep disorder. It often begins in teenage years and features episodes of extreme sleepiness, appetite, mood and behavioural changes.

It can be difficult to diagnose and treat, but the impact on young people and their families is devastating. We currently see about 25 young people with this disorder.

Research activity

We run busy research programmes alongside our clinical services.

These include narcolepsy and brain imaging techniques, and new treatments. This helps us to stay in touch with cutting edge findings, and bring them to the young people we treat as soon as possible. 


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