N-methyl-d-aspartate receptor (NMDA-R) autoantibodies havebeen reported in people with acute psychosis. We hypothesised that theirpresence may be implicated in the aetiology of treatment-refractorypsychosis. We sought to ascertain the point prevalence of NMDA-R antibodypositivity in patients referred to services for treatment-refractorypsychosis. We found that 3 (7.0%) of 43 individuals had low positive NMDA-Rantibody titres. This suggests that NMDA-R autoantibodies are unlikely toaccount for a large proportion of treatment-refractory psychosis.