A number of times over the past few years, SSRI Antidepressants have been the subject of discussion on thyroid forums I have posted on and been moderator for. I also receive frequent emails from thyroid patients asking questions about these drugs in regard to their effect on thyroid hormones in the body. These drugs prompted one of my first-ever searches online because as a newly diagnosed hypothyroid patient in early 2003 and having been prescribed an SSRI antidepressant, I was curious as to how these drugs might affect my thyroid hormone levels. In my case I ended up weaning off the drug because my doctor at the time, in my opinion was jumping the gun so-to-speak in not first allowing my thyroid hormone replacement therapy to relieve my symptoms of anxiety and intermittent low mood. It turns out in my case, my hypothyroid therapy did very well in balancing my emotions and I was not in need of an SSRI antidepressant.

I’m listing some medical research below about antidepressants and their affects on thyroid hormone but let me first express the fact that I’m a firm believer in the ability of these drugs to be extremely effective in people who need them. I do feel however that this is an area of education about these drugs that thyroid patients should have, especially if the drug is added by their doctor after they are already being treated for hypothyroidism with hormone replacement. It’s possible some of these patients will either need their hormone dose adjusted due to the slight lowering effect the drugs have on thyroid hormone or they might need addition of T3 to their hormone replacement therapy (most Dr.s treat with T4 only) if it is not already in their regimen.

Title of study published on U.S. National Institutes of Health stating that SSRI antidepressants have been found to lower thyroid hormone in the body> Peripheral thyroid hormones and response to selective serotonin reuptake inhibitors
QUOTE: "Thyroid hormone levels decreased with treatment, but these decreases did not correlate with clinical improvement." (PubMed Central)


An article citing studies in regard to better improvement in treated hypothyroid patients, placed on SSRI antidepressants when T3 was added to their hormone therapy, titled>‘Supercharge’ antidepressants by adding thyroid hormones/Why hormones help, and new data on SSRI augmentation.
QUOTE: "Three open trials to date have investigated using thyroid hormones to augment SSRIs in treatment-resistant MDD. In a prospective study by Agid and Lerer, 10 of 25 (40%) patients who did not respond to SSRI treatment did so after T3 was added." (The Journal of Family Practice)

(NOTE: MDD above is abbreviation for "Major Depressive Disorder")

In regard to antidepressants actually causing "thyroid dysfunction", the only one actually recognized for doing this is "lithium".

ARTICLE: "How should lithium-induced thyroid dysfunction be managed in patients with bipolar disorder?" (U.S. National Institutes of Health/Journal of Psychiatry & Neuroscience)


Despite the fact that the first research quote above doesn't refer to the lowering of thyroid hormone as "thyroid dysfunction" you could still say it hinders thyroid hormone enough in the body as to merit use of thyroid hormone replacement to supplement the SSRI therapy. Unfortunately, you will find very few doctors who are aware of these studies.