The most common diagnoses that involve the thyroid gland are goiters, hypothyroidism, and hyperthyroidism. A goiter is a condition where your thyroid gland grows larger. Iodine deficiency is the most common cause of goiters. Hypothyroidism is the result of the thyroid gland not producing enough of certain crucial hormones. Symptoms of hypothyroidism include weight gain, fatigue, hair loss, muscle cramps, and depression. Hyperthyroidism commonly referred to as an ‘overactive thyroid’, is the result of the thyroid gland producing too much hormone. Common symptoms include weight loss, tachycardia (rapid heart rate), sweating, changes in the menstrual cycle, and nervousness.