In a case series of 100 patients presenting to psychiatric services with psychotic symptoms, Dalmau and colleagues identified that often young women, with key features such as tiredness and short-term memory impairment, were found to be suffering from NMDA-receptor autoimmune encephalitis (AIE). However, distinguishing AIE from true psychotic illness can be challenging. As a consequence, there is a need to help clinicians identify potential patients suffering from AIE.

To identify relevant clinical features of AIE and to propose a strategy that will help psychiatrists screen for AIE.

A review of the recent literature, and illustration with a clinical case.

AIE should be considered especially in female patients presenting in the context of headache, fever, and viral illness-type prodromes, with atypical psychotic symptoms such as agitation, bizarre behaviour, disinhibition, and poorly formed and segmented delusions. Neurocognitive symptoms such as rapid language disintegration and short term memory loss should also prompt further investigation. Progression of AIE leads to motor dysfunction (seizures, dyskinesia), and secondarily autonomic instability and hypoventilation. A young female with a prolonged and severe episode of manic psychosis presented with some of these features, which is why we considered AIE as a differential diagnosis.

Clinicians should consider AIE when they are faced with a young female presenting with psychotic symptoms and a history of autoimmune illness, with a protracted and unusually severe illness. Investigating for AIE provides an exciting opportunity for psychiatrists to work with neurologists within a multidisciplinary team.