Special section: The Stress Connection
| January 1, 2008
In-Depth Report
Special section: The Stress Connection
Have you ever had a "gut-wrenching" experience? Do certain situations make you "feel nauseous"? Have you ever felt "butterflies" in your stomach? We use these expressions to describe emotional reactions because the gastrointestinal tract is sensitive to emotion. Anger, anxiety, sadness, elation: all of these emotions and many others can trigger symptoms in the gut.
The brain has a direct effect on the stomach: even the thought of eating can release the stomach's juices before food gets there. This connection goes both ways. A troubled intestine can send signals to the brain, just as a troubled brain can send signals to the gut. Therefore, a patient's distressed gut can be as much the cause as the product of anxiety, stress, or depression. That's because the brain and the gastrointestinal (GI) system are intimately connected. So intimately, says Dr. Douglas Drossman, co-director of the University of North Carolina's Center for Functional Gastrointestinal and Motility Disorders, that they should be viewed as one system, rather than two.
This is especially true in cases when the gut is acting up and there's no obvious physical or infectious cause. For such functional GI disorders, trying to heal a distressed gut without considering the impact of stress and emotion is like trying to improve an employee's poor job performance without considering his manager and work environment.
The second brain
To appreciate the impact of stress on the gut, it is helpful to understand the similarities and connections between the brain and the digestive system. The gut is controlled by the enteric nervous system (ENS), a complex system of about 100 million nerves that oversees every aspect of digestion. The ENS is heavily influenced by the central nervous system (CNS) with which it communicates through pathways of nerves. The "second brain," as the ENS is sometimes called, arises from the same tissues as the CNS during fetal development. It has many structural and chemical counterparts in the cranial brain, including sensory and motor neurons as well as glial cells, which support and protect the neurons. And the ENS uses many of the same neurotransmitters, or chemical messengers, as the CNS.
The ENS is embedded in the gut wall and participates in a rich dialogue with the brain during the entire journey of food through the 30-foot-long digestive tract. The ENS cells in the lining of the gut communicate with the brain by way of the autonomic nervous system, which controls the body's vital functions. As part of that system, sympathetic nerves connect the gut to the spinal cord and then to the base of the brain. In addition, parasympathetic nerves pass to and from the base of the brain via the vagus nerve from the upper gut or the sacral nerves from the colon. The gut and brain use their shared neurotransmitters, including acetylcholine and serotonin, to transmit information back and forth by way of the sympathetic and parasympathetic nerves.
This two-way communication system between the gut and the brain (see Figure 4) explains why you stop eating when you're full (sensory neurons in your gut let your brain know that your stomach is distended), or conversely, why anxiety over this morning's exam has ruined your appetite for breakfast (the stress activated your "fight or flight" sympathetic nervous system, inhibiting gastrointestinal secretion and reducing blood flow to the gut).
Figure 4: Closing the pain gate
Have you ever noticed that you feel pain less when you're doing something that requires all your attention? That's because pain is not a one-way street. Your brain can inhibit the pain signals from the gut. Experts explain this with the "gate control" theory. For example, receptors in your intestines, known as afferent receptors, pick up a pain signal and send it to the brain. But certain centers in the spinal cord can regulate the pain. Fibers in these "pain gates" may allow the signal to proceed to the brain, or they may "close the gate" when they receive an inhibiting signal from the brain. This process is sometimes called "down-regulation" of the pain signal. Your brain does this naturally when you are doing something that requires deep concentration, such as playing a sport intensely. Antidepressant medications can also help close the gate by blocking or inhibiting the pain signal to the brain. |
Stress and the functional GI disorders
Given how closely the gut and brain interact, it becomes easier to understand why you might feel nauseated before giving a presentation, or why you have intestinal pain during times of stress. Emotional and psychosocial factors play a role in functional gastrointestinal disorders.
That doesn't mean, however, that functional gastrointestinal illnesses are imagined or "all in your head." Psychology combines with physical factors to cause pain and other bowel symptoms. Psychosocial factors, says Dr. Drossman, influence the actual physiology of the gut, as well as the modulation of symptoms. In other words, stress (or depression or other psychological factors) can affect movement and contractions of the GI tract, cause inflammation, or make you more susceptible to infection.
In addition, research suggests that some people with functional GI disorders perceive pain more acutely than other people do because their brains do not properly regulate pain signals from the GI tract. Stress can make the existing pain seem even worse.
These observations suggest that at least some patients with functional GI conditions might find relief with therapy to reduce stress. And sure enough, a review of 13 studies showed that patients who tried psychologically based approaches had greater improvement in their symptoms compared with patients who received conventional medical treatment.
Is stress causing your symptoms?When evaluating whether your gastrointestinal symptoms — such as heartburn, abdominal cramps, or loose stools — are related to stress, watch for these other common symptoms of stress and report them to your clinician as well. Physical symptoms Stiff or tense muscles, especially in the neck and shoulders Headaches Sleep problems Shakiness or tremors Recent loss of interest in sex Weight loss or gain Restlessness Behavioral symptoms Procrastination Grinding teeth Difficulty completing work assignments Changes in the amount of alcohol or food you consume Taking up smoking, or smoking more than usual Increased desire to be with or withdraw from others Rumination (frequent talking or brooding about stressful situations) Emotional symptoms Crying Overwhelming sense of tension or pressure Trouble relaxing Nervousness Quick temper Depression Poor concentration Trouble remembering things Loss of sense of humor Indecisiveness |
Treating the whole body
Stress-related symptoms in the GI tract vary greatly from one patient to the next, and treatment can vary as well. For example, one person with GERD might describe an occasional, mild burning sensation in the chest, while another complains of excruciating discomfort night after night. As the severity of symptoms varies, so should the therapies, medications, self-help strategies, or even surgeries used to relieve them.
Many patients have mild symptoms that respond quickly to changes in diet or medications. If symptoms do not improve, your clinician may ask you more questions about your medical history and perform some diagnostic tests to rule out a physical abnormality, infection, or cancer. For some people, symptoms improve as soon as a serious diagnosis has been ruled out (another example of how emotional stress affects the gut!). Your doctor may also recommend symptom-specific medications. But sometimes these treatments are not enough. As symptoms become more severe, so does the likelihood that a patient is experiencing some sort of psychological distress.
Often, patients with moderate to severe symptoms, particularly those whose symptoms arise from stressful circumstances, stand to benefit from psychological treatments such as cognitive behavioral therapy, relaxation techniques, and hypnosis. Initially, some patients may be reluctant to accept the role of psychosocial factors in their illness. These treatments do not directly reduce pain or improve symptoms (although these may be indirect benefits). Rather, the goal is to reduce anxiety, encourage healthy behaviors, and help patients cope with the pain and discomfort of their condition.
Cognitive behavioral therapy
Cognitive behavioral therapy, or CBT, involves working with a therapist to learn how thoughts and behaviors affect a person's symptoms and quality of life. The goal is to change counterproductive thoughts and actions and learn new coping skills. This may be accomplished through a number of techniques, including modifying counterproductive thoughts and feelings, stress management and relaxation training, modeling healthy behaviors, and role playing. CBT can reduce the stress of dealing with a functional GI disorder so that the disorder is no longer the focal point of a person's life. As stress decreases, symptoms often improve, and in turn stress and anxiety may improve even further. In a 2003 study of patients with irritable bowel syndrome, Dr. Drossman found that 70% reported less pain, bloating, and diarrhea after 12 weeks of CBT.
A variety of mental health professionals practice CBT, including psychologists, psychiatrists, social workers, and psychiatric nurses. Most cognitive behavioral therapists are not specifically trained in treating irritable bowel syndrome or other functional GI disorders unless they are associated with a clinic that specializes in treating these conditions. More likely, you will be taught more general techniques that you can apply to your specific situation. To find a trained cognitive behavioral therapist, consult your doctor or health plan, or visit the Web site of the Academy of Cognitive Therapy at www.academyofct.org. Make sure your therapist has a license to practice in your state.
Relaxation therapy
Relaxation therapy is a technique that helps people to be more relaxed over all and also to stay more relaxed when confronted by pain or a stressful situation. Therapists use a variety of methods, including progressive muscle relaxation, mental imaging, music, and even aromas, to induce a natural state of relaxation. During and after relaxation, thoughts begin to flow slowly and naturally, muscle tension diminishes, and breathing slows and becomes deeper and more regular. This allows the parasympathetic branch of the autonomic nervous system to take over. The result? The body can relax and digest.
For people with functional or stress-related GI disorders, relaxation therapy can help manage the stress associated with physical discomfort. One small study, for example, found that people with irritable bowel syndrome who practiced a form of relaxation therapy called the Relaxation Response, developed by Harvard Medical School researcher Dr. Herbert Benson, enjoyed significant short- and long-term reductions in pain, bloating, diarrhea, and flatulence. There are many relaxation techniques, including yoga, transcendental meditation, hypnosis, and biofeedback. Many types of health care professionals, including psychologists and behavioral therapists, teach relaxation skills. Ask your doctor for a referral.
Antidepressants for body and mind
A small minority of patients have severe functional GI symptoms that can be debilitating, significantly affecting their day-to-day functioning. It's important for these patients to be screened for anxiety and depression. Patients with severe symptoms have a high frequency of psychological diagnoses, such as anxiety or depression, or a history of loss, abuse, or trauma. In some studies, high rates of prior sexual and physical abuse have been found in patients with functional GI disorders — as high as 56% among patients with severe symptoms. And among patients referred to gastrointestinal clinics — usually those with more severe symptoms — functional bowel disorders often started after a time of extreme stress.
If either anxiety or depression appears to be a factor in a functional GI disorder, specific treatment for anxiety or depression, including referral to a mental health professional, may be needed. Moreover, patients with severe GI symptoms, especially those with chronic pain, may benefit from treatment with antidepressants even if they are not depressed. Although these medications are most often prescribed to help alleviate depression and anxiety, in lower doses they also act to relieve pain. One large analysis of patients with irritable bowel syndrome and functional dyspepsia found that in all 12 studies examined, patients treated with antidepressants showed an improvement in abdominal pain scores compared with placebo. Antidepressants also improve a sense of overall well-being in functional GI disorder patients. And they can benefit gut motility.
There are currently three groups of antidepressant medications that can be used to treat functional GI disorders: tricyclic antidepressants, selective serotonin reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors.
Tricyclic antidepressants. Tricyclic antidepressants (TCAs) include amitriptyline (Elavil), desipramine (Norpramin), and nortriptyline (Pamelor). At full doses, TCAs have considerable side effects. However, when prescribed at doses lower than those used to treat depression, TCAs may be used to relieve pain. Pain is, in part, a matter of perception; the brain may perceive GI pain to be more or less severe based on how well it regulates signals coming from the GI tract. TCAs can turn down the level of pain perceived by the brain by acting on the neurotransmitters (dopamine, serotonin, norepinephrine, and acetylcholine) that are carrying pain impulses between the gut and the brain (see Figure 4). TCAs can also act directly on the gut, reducing the sensitivity of the gut to painful stimuli. In addition, TCAs affect motility (constipation is a common side effect, so they are helpful for individuals with diarrhea), and they help alleviate symptoms of depression.
Selective serotonin reuptake inhibitors. Selective serotonin reuptake inhibitors (SSRIs) include citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft), and fluoxetine (Prozac). SSRIs are less effective than TCAs for pain, but they have fewer side effects. They are a good treatment option for patients with functional GI disorders who also have depression or anxiety.
Serotonin-norepinephrine reuptake inhibitors. Duloxetine (Cymbalta) is one of a newer class of antidepressants called serotonin-norepinephrine reuptake inhibitors (SNRIs). SNRIs act on serotonin and norepinephrine, without the side effects of full-dose TCAs. Although SNRIs have not yet been studied for their effectiveness in fighting functional GI disorders, they are expected to join the arsenal of antidepressants used in this context.
Gut reactionsEarly researchers relied on some remarkable yet basic observations to learn how the digestive tract responds to emotions. In 1833, William Beaumont, a U.S. Army surgeon, was given an inside view when Alexis St. Martin, a French-Canadian traveler, was accidentally shot in the stomach. The wound left a gastric fistula (opening to the skin) that allowed Beaumont not only to observe the pumping, to-and-fro motion of the stomach, but also to see what happened when his patient expressed different emotions. In his journals, Beaumont wrote that when St. Martin showed fear, anger, or impatience, his stomach mucosa grew pale and produced less gastric juice. Studies have since found that powerful emotions can evoke both increased and decreased stomach secretions. In another experiment, a student agreed to let medical researcher Thomas Almy view his sigmoid colon, the section of the lower colon near the rectum, through a sigmoidoscope. During the exam, someone else present mentioned cancer of the colon, and the startled student leapt to the conclusion that this was his diagnosis. The researchers watched the lining of his colon blush and contract rapidly, only to relax and regain its normal color when the student was reassured that he did not have cancer. |
Review Date: 2008-01-01
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