Late luteal phase dysphoric disorder and the thyroid axis revisited

Late luteal phase dysphoric disorder (LLPDD), also known as premenstrual dysphoria, has been etiologically linked to both depression and thyroid disease. We examined baseline and TRH-stimulated thyroid function in 45 otherwise healthy women with prospectively confirmed LLPDD during the follicular and luteal phases of their menstrual cycles. The means of all thyroid variables were normal. Three (6.8%) subjects had elevated baseline TSH (mild hypothyroidism), and 6 (13.3%) had an exaggerated TSH response (delta max TSH) to TRH (subclinical hypothyroidism). A blunted delta max TSH (< 5 mU/L) was found in only 4.4% of the subjects. History of a past major psychiatric diagnosis (mostly depression) or a current personality disorder correlated with a lower delta max TSH. As baseline TSH, using the new ultrasensitive radioimmunometric assay, correlated strongly with delta max TSH, the utility of the TRH challenge is questioned. Our findings suggest that LLPDD is not related to depression on the basis of this marker and that hypothyroidism is not the cause of LLPDD.