Anti-NMDA-receptor encephalitis: an unusual treatable cause of chronic insomnia?

We describe an unusual case of severe and chronic insomnia that proved to be eminently treatable.
Initially presumed to be of primary psychiatric/toxicological origin, certain clinical and paraclinical
clues led us to the diagnosis of NMDA-receptor encephalitis, an immune-mediated disease of the
brain. Our patient responded dramatically to immunotherapy, effectively regaining normal sleep habits
and significantly improving his general and mental health after 25 years of insomnia and drug abuse.
Immune-mediated encephalopathies should be considered in the differential diagnosis of severe sleep
disorders that present with additional neurological signs and symptoms, even when chronic.