Depressed? You may want to check your thyroid

If you’re depressed, and especially if you haven’t responded all that well to antidepressants, you may want to have your thyroid function checked. In fact the American Association of Clinical Endocrinologists states: “The diagnosis of subclinical or clinical hypothyroidism must be considered in every patient with depression.”  That’s recommended because it is well known that when patients have slow metabolism due to low thyroid hormone production from hypothyroidism, they can easily have depression that can respond dramatically to thyroid hormone treatment.  It’s also recommended because many doctors are not thinking to check for low thyroid function in their depressed patients.  Hypothyroidism (high TSH and low T4 on blood tests) is found in 4% of people with depression and That’s good advice, but plenty of doctor ignore it. It’s just easier to write a prescription for antidepressants than to explore a potential underlying cause of so common a symptom as depression.

A review of the literature found that subclinical hypothyroidism (when the TSH is a little high but T4 levels are still normal) occurs in up to 40 percent of people with mood disorders such as depression.  That’s a lot of people but even that is just the tip of the iceberg.

That’s a lot, and I suspect a fair number of these people fall through the cracks when it comes to proper diagnosis aResearchers are totally missing the boat on the importance of thyroid hormones in the treatment of depression because they are looking at the wrong variable.  They are looking only at the thyroid blood tests when they should be looking at the body temperature as well.  They are puzzled by the fact that T4 helps people with hypothyroidism (high TSH on blood tests) while T3 helps people with normal thyroid tests.  However, this is exactly what we’d expect to see with Wilson’s Temperature Syndrome.

Of course a slow metabolism can cause depression and other mood disorders.  Of course low T4 production can cause slow metabolism and low body temperatures, and of course it will respond well to T4.  Of course impaired conversion of T4 to T3 can cause slow metabolism and low body temperatures and of course that can respond well to T3 therapy.

The slow metabolism that shows up on thyroid blood tests (hypothyroidism and subclinical hypothyroidism) is actually much less common than the slow metabolism due to Wilson’s Temperature Syndrome.  It is likely that almost all patients with depression have low body temperatures, and that many of them would gain improvement with the normalization of their body temperatures with T3 therapy.

It can be hard to interpret thyroid tests for subclinical hypothyroidism in the face of depression. When thyroid abnormalities exist, they consist mainly of elevated T4 levels, low T3, elevated rT3, blunted TSH response to TRH, positive antithyroid antibodies, and elevated cerebrospinal fluid TRH concentrations.