Antibody mediated psychosis: a clinical and cognitive profile

Emma Palmer-Cooper1, Thomas Pollak2, Belinda Lennox1; 1Department of Psychiatry, Warneford Hospital, University of Oxford, 2Institute of Psychiatry, Psychology and Neuroscience, King’s College London

Purpose: Research has identified some cases of schizophrenia are mediated by anti-neuronal auto-antibodies that are present in the blood, and either disrupt NMDA receptor function, or the VGKC-complex that influences receptor function. Current prevalence of antibodies in FEP is estimated at 6.5 -9.6%. Case reports have indicate that Ab-positive patients may be clinically atypical (more psychiatrically unwell, increased catatonic symptoms, more severe cognitive impairment and adverse reactions to antipsychotics), however there has been no formal investigation into the clinical or cognitive profile. This study aimed to identify if such a profile is evident and useful to clinicians in identifying Ab-positive patients. Materials and Methods: 227 patients from EIP services in England were screened for NMDAR and VGKC antibodies, and were rated on the PANSS, Catatonia Rating Scale and ACE-III, lifestyle measures and estimated DUP. Results: 20/277 patients were Ab-positive, with no difference in age, gender or ethnicity to Ab-negative patients. There was no difference on PANSS scores or the ACE-III. There was a significant difference on the CRS (p<.01). However, it is unlikely that such a small overall difference (M=1.5) is clinically observable. There was no difference in alcohol consumption, smoking, cannabis use, prodromal symptoms, or family history of psychiatric or auto-immune disorders. There was a significant difference between mean DUP (p<.05); Ab-positive (Mean=1.36, median = 0.1) Ab-negative (mean= 3.98, median =0.9). Conclusion: Overall, while there are subtly significant differences in catatonia profile and DUP, there is no clear phenotype to allow clinicians to discriminate between Ab-positive and Ab-negative patients.

Topic Area: Diagnosis and Phenomenology

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