Hyperthryoidism and “Bipolar Disorder” When Thyroid Imbalance “Masquerades” As A Mood Disorder

Case Study Highlights Clinical Similarity Between Hyperthyroidism And Mania

by Great Western Laboratories

Older patients who suddenly develop symptoms of bipolar disorder may actually be suffering from an undiagnosed thyroid disorder, suggests a recent case study reported in Acta Psychiatrica Scandinavica.

Two physicians report the case of a 65-year-old man with no personal or family history of mental illness, who began experiencing classic symptoms of mania, including intense irritability, hyperactivity, and insomnia. After one month, the patient’s manic symptoms were replaced by depressive episodes fraught with sadness, anxiety, guilt, and disturbed sleep.
Initially diagnosed as a rare case of late-onset bipolar disorder, the man was treated with mood-stabilizing medications and discharged. Results of laboratory evaluations that came in a few days later, however, revealed that the patient was actually hyperthyroid – with elevated levels of thyroid hormones fT3, fT4, and TSH.

With treatment for thyroid dysfunction, the man’s hormone levels normalized, his mental state improved, and physicians were able to cut back mood-stabilizing medications.
“This case illustrates both the clarity with which hyperthyroid disease can mimic the manic state seen in classic bipolar disorder and the necessity of a thorough physical examination, history and laboratory work-up in order to identify possible underlying medical causes of patients who present with manic syndromes,” comments Michael Escamilla, M.D., of the Department of Psychiatry at the University of Texas Health Science Center, in an invited comment on the report.

Thyroid dysfunction is sometimes called the “great imitator” because of the vast array of health disorders it can mimic.

An overactive thyroid gland, or hyperthyroidism, can trigger restlessness, hyperactivity, insomnia and irritability – symptoms that could be mistaken for mania. On the other hand, a thyroid gland that responds sluggishly in a hypothyroid state may result in feelings of coldness, depression, and low energy.

Dr. Escamilla notes that the interplay between mood and thyroid function is a two-way street. While thyroid imbalances can disrupt mood, mood disorders themselves can also impair thyroid function. Hypothyroidism, for example, is estimated to occur in almost one out of every ten bipolar patients not being treated with certain mood-stabilizing medications.
Interestingly, certain drugs used to treat acute mania, such as lithium, may be effective, in part, because they tend to lower thyroid hormone levels. In fact, the intensity of manic symptoms in bipolar patients receiving lithium has been correlated with free thyroxine (fT4) levels, even when thyroid hormones remain within the “clinically normal” range.
Dr. Escamilla suggests that as scientific understanding of the interactions between genetics, biophysiology, and mood dysfunction advances, “it may be only a matter of time before many of the patients who we currently diagnose as having bipolar disorder will actually have more specific designations that describe in detail their underlying pathology.”

NOTE: Comprehensive Thyroid Assessment is important for assessing underlying clinical and subclinical thyroid imbalances linked to a variety of mood disruptions, including chronic anxiety, depression, insomnia, and restlessness. This evaluation of central and peripheral thyroid metabolism can pinpoint hidden causes of treatment dilemmas.
Source: Nath J, Safar R. Late-onset bipolar disorder due to hyperthyroidism. Acta Psychiatr Scand 2001;104:72-75.