Medical problems and depression

Depression often accompanies other types of medical conditions, for complex reasons.

As reported in Harvard Medical School's special health report, Understanding Depression, medical illnesses or medications may be at the root of up to 10%–15% of all cases of depression. Medical conditions can also cause other mood disturbances, such as anxiety or mania.

Among the best-known culprits are two thyroid hormone imbalances. An excess of thyroid hormone (hyperthyroidism) can trigger manic symptoms. Hyperthyroidism occurs in about two and a half million Americans. Hypothyroidism, a condition in which your body produces too little thyroid hormone, often leads to exhaustion and depression. This imbalance affects more than nine million Americans.

Heart disease has also been linked to depression, with up to half of heart attack survivors reporting feeling blue and many having significant depression. Depression can spell trouble for heart patients: It's been linked with slower recovery, future cardiovascular trouble, and a higher risk of dying within about six months. Although doctors have hesitated to give heart patients older depression medications called tricyclic antidepressants (TCAs) because of their impact on heart rhythms, newer drugs such as selective serotonin reuptake inhibitors (SSRIs) seem safe for people with heart conditions.

The following medical conditions have also been associated with mood disorders:

• degenerative neurological conditions, such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, and Huntington's disease
• stroke
• some nutritional deficiencies, such as a lack of vitamin B12
• other endocrine disorders, such as problems with the parathyroid or adrenal glands that cause them to produce too little or too much of particular hormones
• certain immune system diseases, such as lupus
• some viruses and other infections, such as mononucleosis, hepatitis, and HIV
• cancer
• erectile dysfunction in men.

When considering the connection between health problems and depression, an important question to address is which came first, the medical condition or the mood changes. There is no doubt that the stress of having certain illnesses can trigger depression. In other cases, depression precedes the medical illness and may even contribute to it. To find out whether the mood changes occurred on their own or as a result of the medical illness, a doctor carefully considers a person's medical history and the results of a physical exam.

If depression or mania springs from an underlying medical problem, the mood changes should disappear after the medical condition is treated. If you have hypothyroidism, for example, lethargy and depression often lift once treatment regulates the level of thyroid hormone in your blood. In many cases, however, the depression is an independent problem, which means that in order to be successful, treatment must address depression directly.

Have you or someone you know experienced mood changes that were related to an underlying medical condition? What treatments helped?

Dr. Michael W. Kahn is an Assistant Professor in the Department of Psychiatry at Harvard Medical School, and is medical Director of Ambulatory Psychiatry at the Beth Israel Deaconess Medical Center in Boston.

Depression
Nearly 1 in 10 adults will suffer from some form of depression in a given year, affecting not only them, but also their friends and family. Thankfully, years of research and recent breakthroughs have made this serious illness easier to treat. With Understanding Depression, a special health report from Harvard Medical School, you can stay up-to-date on the latest information on depression symptoms and treatments to improve your life—or the life of someone close to you.

Are you Living With Depression? Connect with others with similar health concerns and issues. Click here to join the group.

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