Subclinical Hypothyroidism: Psychiatric Disorders and Symptoms

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

Method: 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.

Results: 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).

Conclusion: 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.