There is increasing recognition in the neurological and psychiatric literature of
patients with so-called isolated psychotic presentations (ie, with no, or minimal,
neurological features) who have tested positive for neuronal autoantibodies (principally
N-methyl-D-aspartate receptor antibodies) and who have responded to immunotherapies.
Although these individuals are sometimes described as having atypical, mild, or attenuated
forms of autoimmune encephalitis, some authors feel that that these cases are sufficiently
different from typical autoimmune encephalitis to establish a new category of so-called
autoimmune psychosis. We briefly review the background, discuss the existing evidence
for a form of autoimmune psychosis, and propose a novel, conservative approach to
the recognition of possible, probable, and definite autoimmune psychoses for use in
psychiatric practice. We also outline the investigations required and the appropriate
therapeutic approaches, both psychiatric and immunological, for probable and definite
cases of autoimmune psychoses, and discuss the ethical issues posed by this challenging
diagnostic category.