12 Surprising Causes of Depression

thyroid-check

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Thyroid disease

When the thyroid, a butterfly-shaped gland in the neck, doesn't produce enough thyroid hormone, it's known as hypothyroidism, and depression is one of its symptoms. This hormone is multifunctional, but one of its main tasks is to act as a neurotransmitter and regulate serotonin levels. If you experience new depression symptoms—particularly along with cold sensitivity, constipation, and fatigue—a thyroid test couldn't hurt. Hypothyroidism is treatable with medication.

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