Depression is a brain disorder that can lead to much emotional anguish. Changes in how your brain functions also can have a big effect on your body. Is it any wonder, then, that depression contributes to a wide array of physical problems that affect everything from your heart to your immune system?
Depression doesn't just cause physical symptoms; it can also increase your risk for -- or may worsen -- certain physical illnesses or conditions. In turn, some illnesses can also trigger depression.
Serotonin acts as a neurotransmitter, a type of chemical that helps relay signals from one area of the brain to another. Although serotonin is manufactured in the brain, where it performs its primary functions, some 90% of our serotonin supply is found in the digestive tract and in blood platelets.
What causes these symptoms of depression? Changes in the brain have an effect on many of the body's systems. For example, abnormal functioning of brain messengers (neurotransmitters) such as serotonin can alter your pain threshold. This means you become more sensitive to pain, especially back pain. Serotonin also affects sleep and lowers sex drive -- nearly half of everybody with depression has problems with sex.
Unfortunately, individuals with depression, as well as their families and health care professionals, often overlook the physical signs and symptoms of depression. In one case, researchers found that sleep troubles, fatigue, and worries about health are reliable indicators of depression in older adults. But, they found, these signs are routinely and incorrectly dismissed as a natural part of aging.
Depression Increases Your Risk of Physical Illness
Depression increases your risk of a number of diseases and other conditions by, for example, increasing levels of stress hormones such as cortisol or adrenaline.
Depression can affect the immune system, making it harder for your body to fight infection. Vaccinations are even less effective in people with depression.
Many of the physical changes caused by depression, such as insomnia or a lack of deep sleep, are thought to weaken your immune system. This can make existing illnesses worse. In turn, physical changes caused either by depression or chronic disease can trigger or worsen depression. All these changes can lead to a vicious cycle that's tough to break without treatment for both depression and any other diseases.