Final answer:
Lithium can affect thyroid functioning by causing hypothyroidism and goiter.
Step-by-step explanation:
Lithium is a medication commonly used to treat bipolar disorder. It can affect thyroid functioning by interfering with the production and release of thyroid hormones. Research has shown that lithium can lead to hypothyroidism, which is the underproduction of thyroid hormones. This can cause symptoms such as weight gain, sensitivity to cold, and reduced mental activity.
Lithium can also cause goiter, which is the enlargement of the thyroid gland. This occurs because lithium can inhibit the uptake of iodine by the thyroid gland, which is necessary for the synthesis of thyroid hormones. When iodine levels are low, the thyroid gland compensates by increasing in size.
In summary, lithium can affect thyroid functioning by causing hypothyroidism and goiter. It is important for individuals taking lithium to have regular thyroid function tests to monitor their thyroid hormone levels.