In a reverse of what I thought I have clinically seen, a recent prospective study finds that low thyroid functioning is not associated with depression. In fact, they found the opposite to be true: a high thyroid function is associated with depression.
Evidently, I was not alone in thinking that low thyroid levels are associated with depression. The study’s authors write that: “Medical guidelines for clinical practice, produced by the American Association of Clinical Endocrinologists, state that ‘the diagnosis of subclinical or clinical hypothyroidism must be considered in every patient with depression.'”
The study, Thyroid Function and the Natural History of Depression: Findings From the Caerphilly Prospective Study (CaPS) and a Meta-analysis, by Williams, Harris, Dayan, et. al., was published on 05/12/2009 in Clinical Endocrinology. Unfortunately, I cannot give you a link because this comes from a subscription service via Medscape. But you can register for this service here.
Here’s a brief summary.
The authors undertook a
- “prospective cohort study of 2269 middle aged men (45–59 years) with thyroid function (total T4 only, TSH unavailable) measured between 1979 and 1983 and with repeat measures of minor psychiatric morbidity (GHQ-30) over a mean of 12·3 years follow-up. We also undertook a systematic review and meta-analysis of population-based studies examining thyroid function and mood.”
Their conclusion is that:
- “we find no evidence…that low thyroid function is associated with depression over the life course. In contrast, we provide evidence…that high normal thyroid function (lower TSH and higher T4) is associated with depression.”
In this case at least, anecdotal clinical evidence was turned upside down.