Who knows the significance of this observation until much more investigation has been done? Maybe it is an artefact of some sort.
It does provoke questions such as: Why do thyroid glands vary in size significantly? Do we need larger thyroid glands in order to continue to produce enough thyroid hormone even when demand is high?
Prim Care Companion CNS Disord. 2015; 17(4): 10.4088/PCC.15l01778.
Published online 2015 Aug 20. doi: 10.4088/PCC.15l01778
Thyroid Gland Volume Is Significantly Smaller in Patients With Psychiatric Disorders Than in Those Without Psychiatric Disorders
Hidetaka Hamasaki, MD
Masafumi Kakei, MD, PhD
Hidekatsu Yanai, MD, PhD
Department of Internal Medicine, National Center for Global Health and Medicine Kohnodai Hospital, Chiba (Drs Hamasaki and Yanai); General Internal Medicine, Community Healthcare Studies, Jichi Medical University Graduate School, Tochigi (Drs Hamasaki and Kakei), Japan
To the Editor: The thyroid gland normally secretes thyroxine and triiodothyronine. A previous study reported that partial substitution of triiodothyronine for thyroxine improved mood and neuropsychological functions in hypothyroid patients treated with only thyroxine,1 suggesting an importance of the integrity of the thyroid gland for neuropsychological functions. It is clear that thyroid hormone plays an important role in the brain, influencing mood and cognition; however, the detail mechanisms remain to be elucidated. Here, we investigated the differences of thyroid gland volume, thyroid hormones, and thyroid autoantibodies between individuals with and without psychiatric disorders.
Full paper (though it is very short) available here:
If you found the quote interesting, please read the rest, especially questions such as whether there was selection bias.