Anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis is a severe form of encephalitis that has been identified within the context of acute neuropsychiatric manifestations. We report the case of an 18-year-old adolescent referred for a first episode of acute psychosis. The clinical picture rapidly deteriorated to a state of catatonia, decreased consciousness and autonomic instability. Detection of highly positive anti-NMDA-R antibodies confirmed the diagnosis of anti-NMDA-R encephalitis. Immunosuppressive treatment and repeated plasma exchange resulted in slow recovery. The literature on diagnosis and treatment of this specific type of encephalitis is reviewed.