Finding and treating subclinical hypothyroidism

Lower TSH and higher T4 levels are associated with current depressive syndrome in young adults

OBJECTIVE

The relationship of individual thyroid function indices to depression in those without a history of prior thyroid dysfunction is uncertain.

METHOD

We examined the relationship between thyroid-stimulating hormone (TSH) and thyroxine (T4) levels and current or lifetime history of depressive symptoms using information from 6869 participants, aged 17-39 years, in the Third National Health and Nutrition Examination Survey without history of thyroid-related illness.

RESULTS

We found that lower TSH and higher T4 levels were associated with current depressive syndrome in men, but only higher T4 levels correlated with current depressive syndrome in women. Lifetime depressive syndrome was associated with neither TSH level nor T4 levels in men or women.

CONCLUSION

These findings suggest that transient or 'state dependent' changes are associated with depression in those without a history of thyroid illness. Further studies to discern whether these depression-associated changes represent distinct endophenotypes of depression should be encouraged.

High serum TSH levels are associated with depression in the elderly

In order to investigate the association between elevated serum TSH levels and depression in the elderly, we conducted a population-based study of 451 over 60-year-old outpatients of a general University Hospital. Patients were divided into Group I (GI) (248 individuals) with high serum TSH levels, but otherwise no important condition or disease, and Group II (GII) (203 patients) with no previous diagnosis of thyroid or mood disease, referred to the hospital because of nonthyroidal severe diseases. All patients were clinically examined and classified according to DMS-IV for mood disturbance and had serum TSH, free T4 levels and antithyroid antibodies measured. High serum TSH levels (11.6+/-14.8 mU/l) were observed in 65/203 (32%) patients of GII. Among these patients, 42/65 (65%) had normal free T4 concentrations (1.23+/-0.98 ng/dl), no clinical manifestation of hypothyroidism and thus were considered to present subclinical hypothyroidism. Depression was observed in 24 cases from GI (9.7%) and 29 from GII (14.3%) and was frequent in the subclinical hypothyroid patients (49%). Our results suggest that mood disturbances are frequent in the elderly with elevated serum TSH levels, but they do not differ in the primary hypothyroid and the nonthyroidal sick patients.