Depression, one of the most common symptoms of hypothyroidism, is often treated with anti-depressant drugs. However, taking the correct hormone medication instead would handle the true cause of such feelings and relieve the person’s symptoms.
Hypothyroidism is a medical condition where the thyroid gland is underactive in its role of secreting the hormones needed to regulate functions of the thyroid. The thyroid gland located inside the neck of the body has the job of releasing hormones that monitor how efficiently and quickly the cells convert the nutrition from food into energy. Thus the gland’s role is to regulate metabolism throughout all the cells of the body.  An underactive thyroid thus gives a lower metabolism rate which mimics depression.
Hypothyroid symptoms can be identical to those of clinical depression.
•           Fatigue
•           Sleepiness
•           Slowing of speech
•           Depression
•           Persistent sadness
•           General apathy
•           Lack of interest in personal relationships
•           Low self-esteem
•           Poor concentration and memory
•           Suicidal thoughts
Medical publications acknowledge that properly done blood tests that measure the hormones secreted by the thyroid and adjusting them back up to normal levels will handle depression symptoms caused by a hypothyroid condition.
In July of 2011 “The Harvard Mental Health Letter” published a article titled “Sometimes Depression Results from an Underactive Thyroid” where Dr. Michael Miller, Editor in Chief, reported that taking the correct hormonal  supplement once a day would restore the depressed person to his or her normal emotional mood.
Yale Medical Group from The Yale School of Medicine published an article “Hypothyroidism and Depression” that explains that hypothyroid symptoms are “indistinguishable from depression.”
These medical findings have appeared in major media reports as well.
The “New York Times” ran an article in its Health section on Nov 22nd, 2011 entitled “For Some, Psychiatric Trouble May Start in Thyroid.”  Though he is a psychiatrist, Dr. Russell Joffe of the North Shore-Long Island Jewish Health System, who is doing research in this area, says that “In the early 20th century, the best descriptions of clinical depression were actually in textbooks on thyroid disease, not psychiatric textbooks.”
Another psychiatrist interviewed had this to say, “It’s the chicken-and-egg question,” said Jennifer Davis, assistant professor of psychiatry and human behavior at Brown University. “Is there an underlying thyroid problem that causes psychiatric symptoms, or is it the other way around?” 
Dr. Davis then said it is common for people with thyroid problems to be given a misdiagnosis of psychiatric illness. 
Meanwhile, knowing that Dr. Joffe’s work will take several years to conduct, a medical doctor who is not a psychiatrist is not going to wait for those results. “Psychiatric symptoms can be vague, subtle and highly individual,” noted Dr. James Hennessey, director of clinical endocrinology at Beth Israel Deaconess Medical Center in Boston. He is going ahead with thyroid hormone balancing for his patients who exhibit depression symptoms and who might have even small underactive thyroid situations.
Fox News published an article on August 17, 2011 “9 Sneaky Causes of Depression”. It  listed  the number one item as “The Weather”, number two as “Smoking” and number three as Thyroid disease, recommending that blood tests could easily determine if that is the cause.
MSNBC on June 22, 2011 ran “Is Your Thyroid on the Fritz?” stating that untreated thyroid disorders can lead to infertility, chronic depression, cardiac ills, or high cholesterol.
Knowing that symptoms of hypothyroidism have been shown to be identical to symptoms of depression, it would make sense for those feeling depressed to get the simple thyroid blood tests done by a competent medical doctor as a first step, since the hormonal pills properly given have no side effects. 
On the other hand the anti-depressants given out by psychiatrists to treat depression symptoms by adjusting “chemical imbalances in the brain” have no blood tests they can give to support to support their claims. Their drugs have many side effects including depression and suicidal thoughts, suicide attempts and, sadly, suicides.
http://www.health.harvard.edu/press_releases/sometimes-depression-results-from-an-underactive-thyroid
http://www.yalemedicalgroup.org/stw/Page.asp?PageID=STW000168
http://www.nytimes.com/2011/11/22/health/for-some-psychiatric-troubles-may-begin-with-the-thyroid.html
http://www.foxnews.com/health/2011/08/16/sneaky-causes-depression/
http://today.msnbc.msn.com/id/43492653/ns/today-today_health/t/your-thyroid-fritz/#.UEz8kJGyOnM