Thyroid dysfunction has been linked to psychiatric disorders, particularly to affective disorders. Moreover, aging of the population receiving mental health care leads to an increased epidemiological risk of thyroid disease.

Assess the prevalence of abnormal thyroid function, and its correlations to clinical factors, in an acute psychiatric inpatients ward dedicated to affective disorders.

Reflect on the clinical relevance of thyroid function screening on admission in mental health care.

Retrospective, descriptive study, concerning inpatient episodes from a 12 month period (January to December 2015) in a ward dedicated to affective disorders, in a tertiary psychiatric hospital.

The prevalence of thyroid dysfunction across all psychiatric diagnostic groups was 11%. Preliminary data has shown higher prevalence in non-elderly women with personality disorder as a main diagnosis (30%, P=0.017). Only women were under thyroid replacement therapy, which was significantly more prevalent in those diagnosed with bipolar disorder.

The relatively high prevalence of thyroid dysfunction underlines the relevance of its screening in mental health inpatients. Our results were consistent with the known epidemiology of thyroid disease. Correlations with bipolar and personality disorder were noted, which can contribute to improve the understanding of clinical-epidemiological relationships between thyroid disease and specific psychiatric disorders.