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

## TL;DR

This study explores the link between anti-thyroid antibodies and specific neuropsychiatric symptoms in women with schizophrenia or mood disorders.

## Contribution

The study identifies neuropsychiatric features associated with anti-thyroid antibodies in women with mental disorders.

## Key findings

- 30.3% of antibody-positive patients showed manic syndrome, and 57.6% showed psychotic syndrome.
- Common neuropsychiatric features included delusions, agitation, irritability, and sleep disorders in antibody-positive patients.
- Catatonia was more prevalent in patients with positive anti-thyroid antibodies.

## Abstract

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.

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.

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.

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-VPatients with positive thyroid autoantibodies(n=33)Manic syndrome10 (30.3%)Psychotic Syndrome19 ( 57.6%)Depression syndrome5 (15.2%)Catatonia10 (30.3%)   Exited6 (18.2%)   Stuporus2 (6.1%)   Fluctuating2 (6.1%)

Table 2.The most common clusters of Neuropsychiatric featuresNPI-Q
Positive Thyroid Autoantibodies(n=33)Delusion15 (45.4%)Agitation/Aggression14 (42.4%)Irrıtability14 (42.4%)Motor abnormality14 (42.4%)Sleep disorder15 (45.4%)Appetite/Eating14 (42.4%)

Neuropsychiatric syndrom-level diagnostic patterns according to DSM-V

The most common clusters of Neuropsychiatric features

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.

None Declared