First psychotic break represents a challenging differential diagnosis for psychiatrists as the clinical outcome depends on an aetiology-directed approach. There is growing focus on detection of treatable causes of psychosis because treatment can alter the natural history of disease. Anti-NMDA-receptor encephalitis is a recently described treatable neuropsychiatric disease presenting with psychiatric symptoms.

Review of epidemiology, clinical presentation, diagnostic tests and differential diagnosis, treatment and prognosis of anti-NMDAr encephalitis.

Case report of a patient diagnosed with anti-NMDAr encephalitis. Review of relevant literature collected from medical internet databases.

Male 15 year-old patient with a previous episode of involuntary movements of the limbs and loss of conscience, presented with distonic contact, behaviour disturbances, sexual stereotypies, agitation and disturbed speech, that evolved with generalized tonic-clonic seizures, global aphasia and sinking of consciousness. A diagnose of anti-NMDAr encephalitis was made and partial recovery was obtained after treatment.

Anti-NMDAr encephalitis is an auto-immune process against synaptic receptors, paraneoplasic or not, detectable by anti-body mesurement in CSF. Most patients develop a multistage illness initially presenting with psychiatric manifestations, progressing to seizures, language disintegration and catatonic states associated with abnormal movements. As patients are frequently treated with antipsychotics, motor abnormalities and catatonia are often interpreted as extrapyramidal effects or neuroleptic malignant syndrome, confounding the diagnosis.

Early recognition and treatment of anti-NMDAr encephalitis improve the outcome. Psychiatrists working in emergency departments and first psychotic break units should be aware of this severe disorder in order to start adequate treatment and prevent negative outcomes