Depression and Anxiety Special Report

Can constant stress literally cause a mood disorder? Possibly. Of course, not everyone with depression or anxiety has experienced a very stressful event — such as the death of a loved one, moving to a new town, or losing a job. And not everyone who is under stress develops depression or anxiety. But stressful events may induce changes in brain chemistry that predispose you to depression and anxiety.

Usually, we think of stress as a bad thing. But at its most basic level, stress is helpful. When your mind senses a dangerous situation — such as an animal about to attack — it triggers your body to react with the “fight or flight” response, which helps you do one of those two things.

The hypothalamus brain region signals your adrenal glands to release a surge of hormones, mostly epinephrine (adrenaline) and cortisol. Epinephrine increases your pulse and breathing rate, sending more blood and oxygen to your muscles and brain to give you a jolt of energy. It also contracts your pupils and helps you focus your vision. Cortisol (“the stress hormone”) boosts glucose levels in the bloodstream and maximizes the brain’s use of the sugar as well as slows down nonessential functions like those of the digestive and reproductive systems, so that your energy can be directed to the emergency at hand.

Your body is well equipped to deal with acute stress, like the animal attack mentioned above. When the stressful event is over, your body’s systems should return to normal. But in today’s world we usually face psychological threats, such as marital discord, financial troubles, or the death of a loved one, which are more chronic and prolonged than immediate physical dangers.

Our bodies exhibit the same stress response, but when there’s no end to the stressful situation, we remain in crisis mode. Our bodies aren’t equipped to deal with these prolonged, elevated levels of stress hormones, and a host of health problems can result. Depression and anxiety are common, as is an increased risk of digestive disorders, heart disease, obesity, and insomnia.

Are You Susceptible? The way that stress can increase the risk of mood disorders isn’t completely understood, but it does seem logical that the stress hormone cortisol plays a role. People with depression and anxiety often have high levels of cortisol. In addition, individuals with Cushing’s disease (in which the adrenal gland produces too much cortisol) often develop depression or anxiety. And users of corticosteroids, a type of therapy for inflammatory disorders that contains an active ingredient similar to cortisol, are at risk for mood disorders.

Genetics most likely plays a role as well, and the current evidence suggests that certain events may trigger more episodes of depression in genetically susceptible people. A study from The American Journal of Psychiatry of 2,164 female twins found that those who had a high genetic risk of depression, meaning that their twin had a history of major depression, were at 2.4 times greater risk for experiencing depression after a significantly stressful event than those with a low genetic risk (whose twin had no history of major depression).

Four traumatic events — death of a close relative, assault, serious marital problems, or divorce or breakup — increased the risk of a depressive episode by almost 6% in the low-risk group, while the risk increased to 14% in those genetically predisposed. Research has also found that people with a family history — but no personal history — of depression have higher cortisol levels than people with no family or personal history of depression, suggesting that they are more genetically vulnerable to mood disorders.

Last, chronically elevated stress levels can make you less likely to eat well, sleep, exercise, and have positive interactions with family and friends; of course, deficiencies in these areas can increase your stress level, creating a vicious circle.

Posted in Depression and Anxiety on September 30, 2009