title: Absence of NMDA receptor antibodies in the rare association between Type 1 Narcolepsy and Psychosis.
abstract: Frequency and mechanisms underlying the association between narcolepsy type 1 (NT1) and psychosis remain unclear with potential role for a common immune pathway. We estimated the frequency of psychosis and its characteristics in NT1 at two European sleep centers (France, n = 381; Spain, n = 161) and measured IgG autoantibodies that recognize the GluN1 subunit of the NMDAR in 9 patients with NT1 with psychosis, and 25 NT1 patients without psychosis. Ten NT1 patients (6 in France, 4 in Spain) were diagnosed with comorbid psychosis, a frequency of 1.8%. One patient reported psychotic symptoms few months before narcolepsy onset, two patients few months after onset, and one patient one year after onset but after modafinil introduction. The six remaining patients reported long delays between NT1 and psychosis onset. Half the patients, mostly male adults, reported onset or worsening of psychotic symptoms after medication. We found no IgG antibodies to NR1/NR2B heteromers of the NMDARs in patients with NT1 with or without psychosis. To conclude, psychosis is rare in NT1, with limited evidence for a key impact of stimulants, and no association with anti-NMDAR antibodies. However, dramatic NT1 and schizophrenia exists especially in early onset NT1, which may lead to inappropriate diagnosis and management.
authors.affiliation: National Reference Centre for Narcolepsy, Sleep Unit, Department of Neurology, Hôpital Gui-de-Chauliac, CHU Montpellier, France.|Inserm, U1061, Université Montpellier 1, Montpellier, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Dauvilliers
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Department of Neurology, Barcelona, Spain.|Multidisciplinary Sleep Disorders Unit, Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Gaig
authors.affiliation: National Reference Centre for Narcolepsy, Sleep Unit, Department of Neurology, Hôpital Gui-de-Chauliac, CHU Montpellier, France.
authors.forename: L
authors.initials: L
authors.lastname: Barateau
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Department of Neurology, Barcelona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Graus
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Department of Neurology, Barcelona, Spain.|Multidisciplinary Sleep Disorders Unit, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Iranzo
authors.affiliation: National Reference Centre for Narcolepsy, Sleep Unit, Department of Neurology, Hôpital Gui-de-Chauliac, CHU Montpellier, France.|Inserm, U1061, Université Montpellier 1, Montpellier, France.
authors.forename: R
authors.initials: R
authors.lastname: Lopez
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Department of Neurology, Barcelona, Spain.|Multidisciplinary Sleep Disorders Unit, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Santamaria
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D005260:Female; D005602:France; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D009290:Narcolepsy / Q000150:complications*; D011618:Psychotic Disorders / Q000473:pathology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000276:immunology*; D013030:Spain
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; C409466:NR1 NMDA receptor; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate