Depression And Anxiety - What Causes Fatigue: Chronic Fatigue

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Depression and anxiety

As many as 20%–40% of people who seek help for ongoing fatigue suffer from depression or anxiety. With depression, fatigue can manifest itself in two ways. One is mental fatigue, specifically a decreased drive or motivation to do things that you once enjoyed. Another is a change in sleep patterns — some people sleep more than usual, others develop insomnia. Either way, they grow weary during the day. Depression doesn't have to be severe to cause fatigue. Dysthymia, a persistent low-level depression, can make a person feel tired or fatigued much of the time.

People with anxiety, on the other hand, are prone to panic, fear, and other high-stress responses, which cause fatigue by increasing levels of stress hormones. These people are also more likely to have chronic high-stress reactions, the most debilitating and energy-robbing kind. Anxiety causes a host of emotional and physical symptoms, including worry, restlessness, and irritability, as well as rapid heartbeat, hyperventilation, upset stomach, or general aches and pains. Many people with anxiety also suffer from depression.

It's impossible to overstate that neither depression nor anxiety is the result of any shortcoming in a person's character. Nor are they conditions that a person can simply "shake off" or "snap out of." These conditions are chemical disorders in the brain, which cause often debilitating symptoms (see "Spotting the symptoms of depression and anxiety").

Only in the last decade or so have scientists actually been able to see the brain while it works, using sophisticated forms of imaging such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). These imaging tools have led to a better understanding of which areas of the brain help regulate mood and other functions that are affected by depression and anxiety. Research suggests that depression may arise from abnormalities within the hypothalamus in the brain and the pituitary gland below the brain, as well as in the adrenal glands atop the kidneys: a trio known as the hypothalamic-pituitary-adrenal (HPA) axis. Together these organs govern a multitude of hormonal activities in the body, including a person's perceived energy level (see Figure 6). National Institute of Mental Health research suggests that consistently having the HPA axis in overdrive may lay the groundwork for depression. Abnormal levels of the neurotransmitter GABA may make a person susceptible to anxiety.

Figure 6: Depression and the HPA axis Depression is a common cause of low energy and fatigue. A trio of hormone-releasing glands — the hypothalamus, pituitary, and adrenal (known as the HPA axis) — govern a multitude of hormonal activities in the body. In the brain, the hypothalamus secretes corticotropin-releasing hormone (CRH), which follows a pathway to the pituitary gland. There it stimulates the secretion of adrenocorticotropic hormone (ACTH), which pulses into the bloodstream. Once ACTH reaches the adrenal glands, it triggers the release of cortisol, a hormone that plays a role in the body's stress response. One theory contends that chronic stress puts the HPA axis into a state of continual overdrive, which could lay the groundwork for depression.

A host of factors influence a person's tendency toward depression or anxiety. One is genes. Someone who has a first-degree relative who suffered a major depression has a somewhat higher risk than the average person of developing depression. The tendency toward anxiety may also be genetic because the brain abnormalities that help cause anxiety can be inherited.

Certain life experiences also come into play. The early loss of a parent, as well as sexual or other physical abuse, increase the risk for depression. Early traumas or difficult current life experiences are probably also necessary to trigger episodes of anxiety. Regardless of the cause, getting help for depression and anxiety is extremely important. Several therapies, including medication and psychotherapy, can relieve the symptoms of depression within a matter of weeks. Certain medications to treat anxiety work almost immediately.

If you suspect that you are suffering from depression or anxiety, start off by seeing your primary care doctor. He or she can assess your symptoms with the goal not only of uncovering depression or anxiety, but also of diagnosing possible underlying medical problems.

Treating depression

If the evaluation points to depression, the doctor may suggest some combination of antidepressant medication, psychotherapy, and lifestyle changes such as exercise.

Medication. Antidepressants work to correct some of the disordered brain chemistry that causes depression. Selective serotonin reuptake inhibitors (SSRIs), one class of antidepressants, increase the brain's level of serotonin, a neurotransmitter that affects mood, arousal, anxiety, impulses, and aggression. SSRIs are the most commonly prescribed medicines for depression. Tricyclic antidepressants, an older class of medication, increase serotonin and also norepinephrine, a neurotransmitter that affects mood, anxiety, and drive. Tricyclic antidepressants are often the best choice for someone with sleep problems, although they should be prescribed with caution in people older than 60 and people with known heart disease.

Controlled studies have found that 65%–85% of people with depression get some relief from antidepressants, compared with 25%–40% of people taking a placebo. But not all antidepressants are equally effective for everyone. People's responses are highly individual. If one antidepressant does not help within a few weeks, the doctor might recommend that you try another one until you feel better — and that includes feeling more energetic.

Psychotherapy. Another effective way to beat depression is psychotherapy with a qualified counselor, such as a psychiatrist, psychologist, social worker, or psychiatric nurse. The combination of psychotherapy with an antidepressant is often an effective strategy.

Exercise. A sustained exercise program can improve the mood of people with mild-to-moderate depression. It might also augment antidepressant treatment for people with severe depression. You don't have to exercise a lot to obtain mental health benefits: Two separate clinical trials found that people who do an average of 30 minutes or more of moderate-intensity aerobic exercise (such as walking or riding a bike) at least three times a week alleviate their depression as effectively as those taking antidepressants or undergoing cognitive behavioral therapy. Besides boosting your mood, exercise can also increase your energy level (see "Boosting your natural energy").

Treating anxiety

As with depression, anxiety can be treated with medications, psychotherapy, or both. The most effective drugs for short-term treatment of anxiety are benzodiazepines, which calm symptoms of anxiety in about half of people with generalized anxiety disorder. But benzodiazepines are generally limited to short-term use because over the long term, people develop a tolerance for them and need increasingly larger doses to produce the same effect.

For long-term treatment of anxiety, there are two options: antidepressants or the anti-anxiety drug buspirone (BuSpar). These medications are often prescribed once a person's anxiety is under control, in order to prevent relapse. In addition, short-term psychotherapy is at least as effective as anti-anxiety medications alone. Cognitive behavioral therapy, which aims to correct ingrained patterns of negative thoughts and behaviors, is especially helpful.

Last updated:	January 23, 2007