Anti-NMDA-receptor encephalitis is subacute disorder that has been recently described in young women and girls who often present neuropsychiatric symptoms as first clinical features; thus, it is common that they receive an initial assessment, diagnose or even treatment by a specialist in Psychiatry.

Presenting a case of Anti-NMDA-receptor encephalitis that was observed at our hospital and the steps taken from its initial assessment by Psychiatry to the final diagnose and treatment by Neurology, our objective is to describe this disorder in order to make it known to the specialists in Psychiatry.

The case is that of a 14 year old girl who presents altered behavior, bizarre delusions and auditory hallucinations with subacute onset. In psychiatric assessment it is noted that the patient presents fever, slight and language impairment: Medical and Neurological assessment are requested. The steps followed to rule out other disorders are presented. SPECT and the detection of specific anti-NMDA-receptor antibodies in serum were necessary for an accurate diagnose.

The detection of specific antibodies is necessary for the diagnose of Anti-NMDA-receptor encephalitis. NMDA receptors are ligand-gated cation channels with crucial roles in synaptic transmission and plasticity. Their alteration could be a pathogenic mechanism in disorders such as epilepsy, dementia and schizophrenia.

Anti-NMDA-receptor encephalitis is a recently described clinical entity that should be taken in consideration to rule out other causes of subacute onset psychiatric symptoms in young women and girls. Its well-defined set of clinical characteristics should become familiar to the specialists in Psychiatry.