Psychiatric management of anti-NMDAR encephalitis: a cohort analysis

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an immune-mediated disorder which requires multi-disciplinary treatment including immunomodulation therapy. First presentation is most commonly to psychiatric services and continuing psychiatric care is required to treat disabling symptoms, such as behaviour disturbance, psychosis and catatonia. There is minimal available evidence to guide symptomatic treatment and concern for increased sensitivity to antipsychotics complicates traditional approaches.

All cases of cerebrospinal fluid positive anti-NMDAR encephalitis tested in Queensland, Australia were identified. Demographic, clinical and therapeutic data were collected and reviewed by two independent clinicians. Pre-specified variables reflecting possible treatment side effects were compared.

The majority of the 30 cases (83%) had early psychiatric symptoms and were treated with antipsychotics (67%), average daily olanzapine equivalence dose of 11.5 mg, prior to immunomodulation therapy. Although there was an 88% reduction in cases with aggression, there was little improvement in psychosis, affective symptoms or catatonia with antipsychotics alone. In the cases with psychiatric symptoms, there was no significant difference in the rate of occurrence of neurological and autonomic symptoms between cases prescribed and not prescribed antipsychotics.

Psychiatric input is imperative for both acute and longer-term management of anti-NMDAR encephalitis. Primary symptomatic treatment should remain immunotherapy and surgery. Antipsychotic medications have particular value in managing agitation and aggression. Potential side effects from antipsychotic treatment are difficult to differentiate from progression of anti-NMDAR encephalitis but there was no evidence in this cohort of increased antipsychotic sensitivity. Treatment with psychotropic medication should be individualised and adjusted during the course of the illness.