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Gert Jan Lammers

Professor by special appointment Sleep Medicine

Prof.dr. G.J. Lammers
+31 71 526 2139

Gert Jan Lammers is professor of Neurology. The titel of his chair is: Sleep disorders, in particular narcolepsy and related vigilance disturbances. He is the medical director of the third line Sleep-Wake Centres of SEIN (Heemstede, Zwolle and Groningen), and also affiliated with the department of Neurology of the LUMC. The Sleep Wake Centre of SEIN has been designated by the NFU as a center of expertise for narcolepsy and related disorders. The current appointment is the first in the Netherlands dedicated to Sleep Medicine. Gert Jan Lammers is the current chair of the Dutch Society for Sleep Medicine (Slaapgeneeskunde Vereniging Nederland, SVNL). He is co-founder of the European Narcolepsy Network (EU-NN) and served as president from 2007-2014.

More information about Gert Jan Lammers


We sleep about a third of our lives. Sleep is a basic and vital function, inseparably linked with other basic body functions such as consciousness, metabolism and circadian rhythm. It is therefore not surprising that sleep disorders have a major impact on well-being and functioning.

Sleep disorders are very prevalent, and sleep disorders may modulate manifestations of neurological and psychiatric disorders.

Despite the great importance of sleep and the greatly increased knowledge in recent decades, it is still enigmatic why we sleep and why there are large differences in sleep needs between people. A better insight in these fundamental questions is important for optimal care for people with sleep disorders. Conversely, we can learn from sleep disorders about the how and why of sleep.

The most common sleep-complaint is sleeplessness, and the most prevalent sleep disorder insomnia. However, also excessive daytime sleepiness is a prevalent complaint. In most cases it will be due to wrong sleep-wake habits causing sleep deprivation, but it can also be a result of a sleep disorder. Not everyone realizes that an increased tendency to sleep during the day is almost always accompanied by impaired sustained attention and sometimes also cognitive complaints. This is not only a problem for the sufferer, but also for society: it leads to reduced productivity and an increased risk of accidents in traffic and at work.

The most prevalent disorder causing excessive daytime sleepiness is sleep apnea. A less common cause is narcolepsy, a condition characterized by an inability to stay awake and focused for long periods of time, but also an inability to sleep for extended periods of time. In addition, intriguing but debilitating symptoms such as muscle weakness triggered by emotions (cataplexy), vivid dream experiences (hypnagogic hallucinations) and a short-lasting inability to move when falling asleep or waking up (sleep paralysis) may be present. Narcolepsy is caused by the selective disappearance of hypocretin (also called orexin)-producing cells in the brain. Gert Jan Lammers discovered this in collaboration with researcher from Stanford University.


Gert Jan Lammers current research line focuses on follow-up questions that arose from the discovery that narcolepsy is caused by hypocretin deficiency. Topics are: Do the hypocretin cells disappear due to an autoimmune reaction? What is the physiological function of hypocretin beyond sleep(regulation)? What is the best way to treat narcolepsy? What do we learn from the discoveries related to narcolepsy and the role of hypocretin, and can we use the knowledge to improve treatment of other sleep disorders?


In the current bachelor’s and master’s courses in medicine there is little attention for healthy sleep as part of a healthy lifestyle, nor for sleep disorders, their recognition, prevention and treatment. Part of the teaching assignment is to expand the educational offer in the field of sleep and sleep medicinen in the curriculum of the LUMC.

Academic career

Gert Jan Lammers studied medicine at the University of Groningen. At the LUMC (then AZL) he was trained as a neurologist and clinical neurophysiologist. Since then he has been appointed as a general neurologist at the LUMC. In 1999 he obtained his PhD at Leiden University with a thesis entitled: “Narcolepsy”. In 2013 he obtained the qualification "Somnologist" from the European Sleep Research Society ". In the same year he founded a third-line sleep-wake center in Heemstede as new brench of SEIN. Since 2015 he has been medical director of all Sleep-Wake centres of SEIN (Heemstede, Zwolle and Groningen).

Professor by special appointment Sleep Medicine

  • Faculteit Geneeskunde
  • Divisie 3
  • Neurologie

Work address

LUMC Main Building
Albinusdreef 2
2333 ZA Leiden
Room number K5Q103



  • Hypersomnia Foundation, Amerikaanse patientenvereniging Lid medische adviesraad
  • Independent Data Monitoring Committee voor de DORA onderzoeken van Idorsia Lid
  • International Classification of Sleep Disorders-3 Lid van het revisie team van
  • Jazz Pharmaceuticals Consultant
  • Nationale Slaapcongres Voorzitter van het organisatie comite
  • Nederlandse Vereniging voor Narcolepsie Lid medische adviesraad
  • NLS Pharmaceuticals Lid advisory board
  • Restless Legs Stichting Lid medische adviesraad
  • Slaapgeneeskunde Vereniging Nederland Voorzitter
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