Subclinical hypothyroidism: psychiatric disorders and symptoms

To evaluate the prevalence of psychiatric disorders and symptoms in patients with subclinical hypothyroidism.

Ninety-four outpatients with at least two elevated serum thyrotrophin levels (> 4 microU/ml) and normal FT4, and 43 euthyroid outpatients, both groups from HUCFF-UFRJ, were evaluated. Psychiatric diagnosis was based on the Structured Clinical Interview Diagnostic for the DSM-IV axis I (SCID-I/DSM-IV), the psychopathological symptoms on Hamilton anxiety and depression scales, and the Beck Inventory.

Our data showed an increased prevalence of psychiatric disorders in the subclinical hypothyroidism patients when compared to the euthyroid group (45.7% vs 25.6%; p = 0.025), mood disorders being the most frequent. The prevalence of depressive symptoms based on Beck's Scale among subclinical hypothyroidism patients was about 2.3 times higher than among euthyroid ones (45.6% vs 20.9%, p = 0.006). Anxiety symptoms were also more frequent among subclinical hypothyroidism patients (87.0% vs 60.5%, p < 0.001), mainly clinical anxiety (44.6% vs 23.3%; p = 0.001).

Our results showed a significant association of subclinical hypothyroidism with psychiatric disorders and an increased frequency of subsyndromic depression and anxiety symptoms in subclinical hypothyroidism in relation to the euthyroid group.