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.


METHODS
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.


CONCLUSIONS
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.
Forman-Hoffman
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Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242-1000, USA.
Philibert
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RA
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D003710:Demography; D003866:Depressive Disorder / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D017678:Sex Distribution; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*
D013972:Thyrotropin; D013974:Thyroxine