Association of anti-thyroid autoantibodies with neuropsychiatric features in patients with affective and schizophrenia spectrum disorders

Introduction A growing body of evidence has shown the association between autoimmune thyroiditis and mental illness (Rege et al. AUS N J S Psychiatry 2013; 300 141-154). Identifying the neuropsychiatric features associated with thyroid antibody positivity could have significant implications for diagnostic and therapeutic strategies. However, the link between anti-thyroid antibodies and precise underlying pathophysiology requires future research. Objectives The aim of the present study was to conduct a retrospective evolution in patients diagnosed with schizophrenia spectrum disorder and affective disorder who were screened for anti-thyroid antibodies at the time of their hospitalization and to investigate neuropsychiatric features of anti-thyroid antibody-positive patients. Methods A total of 143 inpatients diagnosed with schizophrenia spectrum disorders and affective disorders between 2021 and 2023 were screened for anti-thyroid antibodies such as thyroid peroxidase (TPO) and thyroglobulin (TG). All patients were women. In order to elucidate the subsequent neuropsychiatric clinical features of individuals with positive anti-thyroid antibodies, the retrospective examination was conducted based on Neuropsychiatric Invetory-Q (NPI-Q) and DSM-V diagnostic criteria utilized at the time of hospitalization. Results The main age of the patients was 48.2 (SD 10.4). A total of 143 inpatients with schizophrenia spectrum disorders and affective disorders were screened for anti-thyroid antibodies at the time of their hospitalizations. %23.1 (n=33) tested positive for at least one of the anti-TG or anti-TPO. All patients were euthyroid. The neuropsychiatric diagnoses are shown in Table 1. The most common neuropsychiatric features assessed by NPI-Q are shown in Table 2. 12.1% (n=4) of all patients were treated with IV steroid Pulse therapy. Table 1. Neuropsychiatric syndrom-level diagnostic patterns according to DSM-V Patients with positive thyroid autoantibodies (n=33) Manic syndrome 10 (30.3%) Psychotic Syndrome 19 ( 57.6%) Depression syndrome 5 (15.2%) Catatonia 10 (30.3%) Exited 6 (18.2%) Stuporus 2 (6.1%) Fluctuating 2 (6.1%) Table 2. The most common clusters of Neuropsychiatric features NPI-Q Positive Thyroid Autoantibodies (n=33) Delusion 15 (45.4%) Agitation/Aggression 14 (42.4%) Irrıtability 14 (42.4%) Motor abnormality 14 (42.4%) Sleep disorder 15 (45.4%) Appetite/Eating 14 (42.4%) Conclusions In particular, in a subset of schizophrenia spectrum disorder or affective disorder patients with positive anti-thyroid antibodies may indicate autoimmunity, especially in cases where catatonic symptoms dominate the clinical presentation. Disclosure of Interest None Declared