News Release

Hypothyroidism clearly linked to mood swings

Results of molecular imaging of brain metabolic activity with PET released at SNM's 54th Annual Meeting June 2–6 in Washington, D.C.

Peer-Reviewed Publication

Society of Nuclear Medicine and Molecular Imaging

WASHINGTON, D.C.—Hypothyroidism is often associated with mood changes like depression lethargy. Researchers, studying underlying brain processes in search of "why" this happens, reported their results at the 54th Annual Meeting of SNM, the world's largest society for molecular imaging and nuclear medicine professionals.

"The aim of our study was to investigate—with positron emission tomography (PET) imaging—how physical health and mental health are interrelated," said Waltraud Eichhorn, a nuclear medicine physician at Johannes Gutenberg University in Mainz, Germany. "We found that hypothyroidism is correlated to regional metabolic changes in the thalamus—an area of the brain that helps process information from the senses and transmit it to other parts of the brain" she said. "In other words, hypothyroid patients—compared to healthy individuals—have decreased metabolism in special parts of the brain that are responsible for processing information, " said Eichhorn. "Remarkably, this reduction in metabolism remains detectable after thyroid hormone replacement therapy," she added.

The thyroid, a butterfly-shaped gland in the neck just above the collarbone, is an endocrine gland that makes hormones and helps set a body's metabolism (how the body gets energy from food). Hypothyroidism, a condition in which your body produces too little thyroid hormone, often leads to exhaustion and depression, affecting millions of Americans, many of them women or the elderly. There are 27 million Americans who have underactive or overactive thyroid glands, but more than half remain undiagnosed, according to recent statistics.

Hypothyroidism can be treated by doses of thyroid hormone. Once the blood levels of thyroid hormone reach a normal range—called euthyroid—lethargy and depression often lift. However, in some patients, the depression persists, which means that successful therapy must address depression directly.

In this study, 10 patients with hypothyroidism underwent a cerebral 18-FDG/PET examination. She indicated that additional research is needed to determine whether special brain regions are responsible for increased depression or anxiety in patients suffering from hypothyroidism.

PET is a safe, highly specialized, noninvasive imaging technique that uses short-lived radioactive substances to produce three-dimensional images of those substances functioning within the body. A special type of camera works with computers to provide precise pictures of the areas of the body being imaged and molecular images of the body's biological functions.


Scientific Poster 1228: W.A. Eichhorn, K. Bose, H. Buchholz, T. Siessmeier and M. Schreckenberger, Nuclear Medicine Department, and U. Egle, Department of Psychosomatic Medicine and Psychotherapy, all at Johannes Gutenberg University, Mainz, Germany; P. Bartenstein, Department of Nuclear Medicine, Ludwig Maximilians University, Muenchen, Germany; and G. Kahaly, Department of Medicine I, Johannes Gutenberg University, Mainz, Germany, "Neuronal Correlates of Overt Hypothyroidism Measured by FDG PET," SNM's 54th Annual Meeting, June 2–6, 2007.

About SNM—Advancing Molecular Imaging and Therapy

SNM is holding its 54th Annual Meeting June 2–6 at the Washington Convention Center in Washington, D.C. Session topics for the 2007 meeting include brain amyloid imaging, hybrid imaging, molecular imaging in clinical drug development and evaluation, functional brain imaging in epilepsy and dementia, imaging instrumentation, infection imaging, lymphoma and thyroid cancer, cardiac molecular imaging, general nuclear medicine, critical elements of care in radiopharmacy and more.

SNM is an international scientific and professional organization of more than 16,000 members dedicated to promoting the science, technology and practical applications of molecular and nuclear imaging to diagnose,manage and treat diseases in women, men and children. Founded more than 50 years ago, SNM continues to provide essential resources for health care practitioners and patients; publish the most prominent peer-reviewed journal in the field (the Journal of Nuclear Medicine); host the premier annual meeting for medical imaging; sponsor research grants, fellowships and awards; and train physicians, technologists, scientists, physicists, chemists and radiopharmacists in state-of-the-art imaging procedures and advances. SNM members have introduced—and continue to explore—biological and technological innovations in medicine that noninvasively investigate the molecular basis of diseases, benefiting countless generations of patients. SNM is based in Reston, Va.; additional information can be found online at

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