How often do you experience stress in your daily life? Never? Rarely? Sometimes? Or frequently? When pollsters put a similar question to other collegians, some 85 percent recalled experiencing stress during the last three months—and most said it had disrupted their schoolwork at least once (Associated Press, 2009). On entering college or university, 18 percent of men and 39 percent of women reported having been “frequently overwhelmed” by all they had to do during the past year (Pryor et al., 2011).

Stress often strikes without warning. Imagine being 21-year-old Ben Carpenter, who experienced the world’s wildest and fastest wheelchair ride. As he crossed a street, his wheelchair handles got stuck in a semi-truck’s grille. The driver, unaware of the mishap, took off down the highway, pushing the wheelchair at 50 miles per hour! “It was very scary,” said Ben, who has muscular dystrophy.

In this section, we take a closer look at stress—what it is and how it affects our health and well-being. Let’s begin with some basic terms.

12-15 What events provoke stress responses, and how do we respond and adapt to stress?

Stress is a slippery concept. We sometimes use the word informally to describe threats or challenges (“Ben was under a lot of stress”), and at other times our responses (“Ben experienced acute stress”). To a psychologist, the dangerous truck ride was a stressor. Ben’s physical and emotional responses were a stress reaction. And the process by which he related to the threat was stress. Thus, stress is the process of appraising and responding to a threatening or challenging event (FIGURE 12.20). Stress arises less from events themselves than from how we appraise them (Lazarus, 1998). One person, alone in a house, ignores its creaking sounds and experiences no stress; someone else suspects an intruder and becomes alarmed. One person regards a new job as a welcome challenge; someone else appraises it as risking failure.

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When short-lived, or when perceived as challenges, stressors can have positive effects. A momentary stress can mobilize the immune system for fending off infections and healing wounds (Segerstrom, 2007). Stress also arouses and motivates us to conquer problems. In a Gallup World Poll, those who were stressed but not depressed reported being energized and satisfied with their lives. This is the opposite of the lethargy reported by those who were depressed but not stressed (Ng et al., 2009). Championship athletes, successful entertainers, and great teachers and leaders all thrive and excel when aroused by a challenge (Blascovich & Mendes, 2010). Compared with nonleaders, military and business leaders produce lower-than-average levels of stress hormones and report lower anxiety levels (Sherman et al., 2012). Having conquered a major stressor, some people emerge with stronger self-esteem and a deepened spirituality and sense of purpose. Indeed, experiencing some stress early in life builds resilience (Seery, 2011). Adversity can beget growth.

But extreme or prolonged stress can harm us. Demanding jobs that mentally exhaust workers also damage their physical health (Huang et al., 2010). Pregnant women with overactive stress systems tend to have shorter pregnancies, which pose health risks for their infants (Entringer et al., 2011).

So there is an interplay between our heads and our health. That isn’t surprising. Behavioral medicine research provides a reminder of one of contemporary psychology’s overriding themes: Mind and body interact; everything psychological is simultaneously physiological. Before exploring that interplay, let’s look more closely at stressors and stress reactions.

Stressors fall into three main types: catastrophes, significant life changes, and daily hassles. All can be toxic.

Catastrophes Catastrophes are unpredictable large-scale events, such as earthquakes, floods, wildfires, and storms. After such events, damage to emotional and physical health can be significant. In the four months after Hurricane Katrina, New Orleans’ suicide rate reportedly tripled (Saulny, 2006). And in surveys taken in the three weeks after the 9/11 terrorist attacks, 58 percent of Americans said they were experiencing greater-than-average arousal and anxiety (Silver et al., 2002). In the New York area, people were especially likely to report such symptoms, and sleeping pill prescriptions rose by a reported 28 percent (HMHL, 2002; NSF, 2001). Extensively watching 9/11 terrorist attack television footage predicted worse health outcomes two to three years later (Silver et al., 2013).

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For those who respond to catastrophes by relocating to another country, the stress may be twofold if the trauma of uprooting and family separation combine with the challenges of adjusting to a new culture’s language, ethnicity, climate, and social norms (Pipher, 2002; Williams & Berry, 1991). In the first half-year, before their morale begins to rebound, newcomers often experience culture shock and deteriorating well-being (Markovizky & Samid, 2008). In years to come, such relocations may become increasingly common due to climate change.

Significant Life Changes Life transitions—leaving home, becoming divorced, losing a job, having a loved one die—are often keenly felt. Even happy events, such as getting married, can be stressful. Many of these changes happen during young adulthood. One survey, in which 15,000 Canadian adults were asked whether “You are trying to take on too many things at once,” found the highest stress levels among young adults (Statistics Canada, 1999). Young adult stress appeared again when 650,000 Americans were asked if they had experienced a lot of stress “yesterday” (FIGURE 12.21).

Some psychologists study the health effects of life changes by following people over time. Others compare the life changes recalled by those who have or have not suffered a specific health problem, such as a heart attack. In such studies, those recently widowed, fired, or divorced have been more vulnerable to disease (Dohrenwend et al., 1982; Strully, 2009). One Finnish study of 96,000 widowed people found that the survivor’s risk of death doubled in the week following a partner’s death (Kaprio et al., 1987). A cluster of crises—losing a job, home, and partner—puts one even more at risk.

Daily Hassles Events don’t have to remake our lives to cause stress. Stress also comes from daily hassles—spotty phone connections, aggravating housemates, long lines at the store, too many things to do, e-mail and text spam, and loud talkers behind us (Lazarus, 1990; Pascoe & Richman, 2009; Ruffin, 1993). Some people shrug off such hassles. For others, the everyday annoyances add up and take a toll on health and well-being.

Many people face more significant daily hassles. As the Great Recession of 2008–2009 bottomed out, Americans’ most oft-cited stressors related to money (76 percent), work (70 percent), and the economy (65 percent) (APA, 2010). In impoverished areas—where many people routinely face inadequate income, unemployment, solo parenting, and overcrowding—such stressors are part of daily life.

Daily economic pressures may be compounded by anti-gay prejudice or racism, which—like other stressors—can have both psychological and physical consequences (Lick et al., 2013; Pascoe & Richman, 2009; Schetter et al., 2013). Thinking that some of the people you encounter each day will dislike you, distrust you, or doubt your abilities makes daily life stressful. When prolonged, such stress takes a toll on our health, especially our cardiovascular system. For many African-Americans, stress helps drive up blood pressure levels (Mays et al., 2007; Ong et al., 2009).

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Medical interest in stress dates back to Hippocrates (460–377 b.c.e.). In the 1920s, Walter Cannon (1929) confirmed that the stress response is part of a unified mind-body system. He observed that extreme cold, lack of oxygen, and emotion-arousing events all trigger an outpouring of the stress hormones epinephrine and norepinephrine from the core of the adrenal glands. When alerted by any of a number of brain pathways, the sympathetic nervous system arouses us, preparing the body for the wonderfully adaptive response that Cannon called fight or flight. It increases heart rate and respiration, diverts blood from digestion to the skeletal muscles, dulls feelings of pain, and releases sugar and fat from the body’s stores.

Since Cannon’s time, physiologists have identified an additional stress response system. On orders from the cerebral cortex (via the hypothalamus and pituitary gland), the outer part of the adrenal glands secrete glucocorticoid stress hormones such as cortisol. The two systems work at different speeds, explained biologist Robert Sapolsky (2003): “In a fight-or-flight scenario, epinephrine is the one handing out guns; glucocorticoids are the ones drawing up blueprints for new aircraft carriers needed for the war effort.” The epinephrine guns were firing at high speed during an experiment inadvertently conducted on a British Airways San Francisco to London flight. Three hours after takeoff, a mistakenly played message told passengers the plane was about to crash into the sea. Although the flight crew immediately recognized the error and tried to calm the terrified passengers, several required medical assistance (Associated Press, 1999).

Canadian scientist Hans Selye’s (1936, 1976) 40 years of research on stress extended Cannon’s findings. His studies of animals’ reactions to various stressors, such as electric shock and surgery, helped make stress a major concept in both psychology and medicine. Selye proposed that the body’s adaptive response to stress is so general that, like a single burglar alarm, it sounds, no matter what intrudes. He named this response the general adaptation syndrome (GAS), and he saw it as a three-phase process (FIGURE 12.22). Let’s say you suffer a physical or an emotional trauma.

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Selye’s basic point: Although the human body copes well with temporary stress, prolonged stress can damage it. Childhood stress gets under the skin, leading to greater adult stress responses and disease risk (Miller et al., 2011). The brain’s production of new neurons also slows and some neural circuits degenerate (Dias-Ferreira et al., 2009; Mirescu & Gould, 2006). One study found shortening of telomeres (DNA pieces at the ends of chromosomes) in women who suffered enduring stress as caregivers for children with serious disorders (Epel et al., 2004). Telomere shortening is a normal part of the aging process; when telomeres get too short, the cell can no longer divide and it ultimately dies. The most stressed women had cells that looked a decade older than their chronological age, which helps explain why severe stress seems to age people. Even fearful, easily stressed rats have been found to die sooner (after about 600 days) than their more confident siblings, which average 700-day life spans (Cavigelli & McClintock, 2003).

There are other ways to deal with stress. One option is a common response to a loved one’s death: Withdraw. Pull back. Conserve energy. Faced with an extreme disaster, such as a ship sinking, some people become paralyzed by fear. Another option (found often among women) is to give and seek support (Taylor et al., 2000, 2006). This tend-and-befriend response is demonstrated in the outpouring of help after natural disasters.

Facing stress, men more often than women tend to withdraw socially, turn to alcohol, or become aggressive. Women more often respond to stress by nurturing and banding together. This may in part be due to oxytocin, a stress-moderating hormone associated with pair bonding in animals and released by cuddling, massage, and breast feeding in humans (Campbell, 2010; Taylor, 2006). Brain scans reflect such stress-response differences: In women, areas important for face processing and empathy become more active; in men, these areas become less active (Mather et al., 2010).

It often pays to spend our resources in fighting or fleeing an external threat. But we do so at a cost. When stress is momentary, the cost is small. When stress persists, the cost may be much higher, in the form of lowered resistance to infections and other threats to mental and physical well-being.

12-16 How does stress make us more vulnerable to disease?

To study how stress, and healthy and unhealthy behaviors influence health and illness, psychologists and physicians have created the interdisciplinary field of behavioral medicine, integrating behavioral and medical knowledge. Health psychology provides psychology’s contribution to behavioral medicine. The subfield of psychoneuroimmunology, focuses on mind-body interactions (Kiecolt-Glaser, 2009). This awkward name makes sense when said slowly: Your thoughts and feelings (psycho) influence your brain (neuro), which influences the endocrine hormones that affect your disease-fighting immune system. And this subfield is the study of (ology) those interactions.

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If you’ve ever had a stress headache, or felt your blood pressure rise with anger, you don’t need to be convinced that our psychological states have physiological effects. Stress can even leave you less able to fight off disease because your nervous and endocrine systems influence your immune system (Sternberg, 2009). You can think of the immune system as a complex surveillance system. When it functions properly, it keeps you healthy by isolating and destroying bacteria, viruses, and other invaders. Four types of cells are active in these search-and-destroy missions (FIGURE 12.23).

Your age, nutrition, genetics, body temperature, and stress all influence your immune system’s activity. When your immune system doesn’t function properly, it can err in two directions:

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Stress can also trigger immune suppression by reducing the release of disease-fighting lymphocytes. This has been observed when animals were stressed by physical restraints, unavoidable electric shocks, noise, crowding, cold water, social defeat, or separation from their mothers (Maier et al., 1994). One study monitored immune responses in 43 monkeys over six months (Cohen et al., 1992). Half were left in stable groups. The rest were stressed by being housed with new roommates—3 or 4 new monkeys each month. By the end of the experiment, the socially disrupted monkeys had weaker immune systems.

Human immune systems react similarly. Some examples:

The stress effect on immunity makes physiological sense. It takes energy to track down invaders, produce swelling, and maintain fevers. Thus, when diseased, your body reduces its muscular energy output by decreasing activity and increasing sleep. Stress does the opposite. It creates a competing energy need. During an aroused fight-or-flight reaction, your stress responses divert energy from your disease-fighting immune system and send it to your muscles and brain. This renders you more vulnerable to illness. The point to remember: Stress does not make us sick, but it does alter our immune functioning, which leaves us less able to resist infection.

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We know that stress suppresses immune system functioning. What does this mean for people with AIDS (acquired immune deficiency syndrome)? As its name tells us, AIDS is an immune disorder, caused by the human immunodeficiency virus (HIV). Although AIDS-related deaths have decreased 29 percent since 2001, AIDS remains the world’s sixth leading cause of death and Africa’s number one killer (UNAIDS, 2013; WHO, 2013).

Ironically, if a disease is spread by human contact (as AIDS is, through the exchange of bodily fluids, primarily semen and blood), and if it kills slowly (as AIDS does), it can be lethal to more people. Those who acquire HIV often spread it in the highly contagious first few weeks before they know they are infected. Worldwide, some 2.3 million people—slightly more than half of them women—became infected with HIV in 2012, often without their awareness (UNAIDS, 2013). Years after the initial infection, when AIDS appears, people have difficulty fighting off other diseases, such as pneumonia.

Stress cannot give people AIDS. But could stress and negative emotions speed the transition from HIV infection to AIDS? And might stress predict a faster decline in those with AIDS? An analysis of 33,252 participants from around the world suggest the answer to both questions is Yes (Chida & Vedhata, 2009). The greater the stress that HIV-infected people experience, the faster their disease progresses.

Would efforts to reduce stress help control the disease? Again, the answer appears to be Yes. Educational initiatives, bereavement support groups, cognitive therapy, relaxation training, and exercise programs that reduce distress have all had positive consequences for HIV-positive people (Baum & Posluszny, 1999; McCain et al., 2008; Schneiderman, 1999). But compared with available drug treatments, the benefits have been small.

Although AIDS is now more treatable than ever before, preventing HIV infection is a far better option. This is the focus of many educational programs, such as the ABC (Abstinence, Be faithful, Condom use) program that has been used with seeming success in Uganda (Altman, 2004; UNAIDS, 2005). In addition to such programs that seek to influence sexual norms and behaviors, today’s combination prevention programs also include medical strategies (such as drugs and male circumcision that reduce HIV transmission) and efforts to reduce social inequalities that increase HIV risk (UNAIDS, 2010).

Stress does not create cancer cells. But in a healthy, functioning immune system, lymphocytes, macrophages, and NK cells search out and destroy cancer cells and cancer-damaged cells. If stress weakens the immune system, might this weaken a person’s ability to fight off cancer? To explore a possible connection between stress and cancer, experimenters have implanted tumor cells in rodents or given them carcinogens (cancer-producing substances). They then exposed some rodents to uncontrollable stress, such as inescapable shocks, which weakened their immune systems (Sklar & Anisman, 1981). Stressed rodents, compared with their unstressed counterparts, developed cancer more often, experienced tumor growth sooner, and grew larger tumors.

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Does this stress-cancer link also hold with humans? The results are mixed. Some studies find that people are at increased risk for cancer within a year after experiencing depression, helplessness, or bereavement (Chida et al., 2008; Steptoe et al., 2010). In one large Swedish study, the risk of colon cancer was 5.5 times greater among people with a history of workplace stress than among those who reported no such problems. This difference was not due to group differences in age, smoking, drinking, or physical characteristics (Courtney et al., 1993). Other studies, however, have found no link between stress and human cancer (Coyne et al., 2010; Petticrew et al., 1999, 2002). Concentration camp survivors and former prisoners of war, for example, do not have elevated cancer rates.

One danger in hyping reports on emotions and cancer is that some patients may then blame themselves for their illness: “If only I had been more expressive, relaxed, and hopeful.” A corollary danger is a “wellness macho” among the healthy, who take credit for their “healthy character” and lay a guilt trip on the ill: “She has cancer? That’s what you get for holding your feelings in and being so nice.” Dying thus becomes the ultimate failure.

It’s important enough to repeat: Stress does not create cancer cells. At worst, it may affect their growth by weakening the body’s natural defenses against multiplying malignant cells (Antoni & Lutgendorf, 2007). Although a relaxed, hopeful state may enhance these defenses, we should be aware of the thin line that divides science from wishful thinking. The powerful biological processes at work in advanced cancer or AIDS are not likely to be completely derailed by avoiding stress or maintaining a relaxed but determined spirit (Anderson, 2002; Kessler et al., 1991). And that explains why research has consistently indicated that psychotherapy does not extend cancer patients’ survival (Coyne et al., 2007, 2009; Coyne & Tennen, 2010).

12-17 Why are some of us more prone than others to coronary heart disease?

Depart from reality for a moment. In this new world, you wake up each day, eat your breakfast, and check the news. Political coverage buzzes, local events snap up airtime, and your favorite sports team occasionally wins. But there is a fourth story: Four 747 jumbo jet airlines crashed yesterday and all 1642 passengers died. You finish your breakfast, grab your books, and head to class. It’s just an average day.

Replace airline crashes with coronary heart disease, the United States’ leading cause of death, and you have re-entered reality. About 600,000 Americans die annually from heart disease (CDC, 2013). Heart disease occurs when the blood vessels that nourish the heart muscle gradually close. High blood pressure and a family history of the disease increase the risk. So do smoking, obesity, a high-fat diet, physical inactivity, and a high cholesterol level.

Stress and personality also play a big role in heart disease. The more psychological trauma people experience, the more their bodies generate inflammation, which is associated with heart and other health problems (O’Donovan et al., 2012). Plucking a hair and measuring its level of cortisol (a stress hormone) can help predict whether a person will have a future heart attack (Pereg et al., 2011).

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Type A Personality In a now-classic study, Meyer Friedman, Ray Rosenman, and their colleagues tested the idea that stress increases vulnerability to heart disease by measuring the blood cholesterol level and clotting speed of 40 U.S. male tax accountants at different times of year (Friedman & Ulmer, 1984). From January through March, the test results were completely normal. Then, as the accountants began scrambling to finish their clients’ tax returns before the April 15 filing deadline, their cholesterol and clotting measures rose to dangerous levels. In May and June, with the deadline past, the measures returned to normal. For these men, stress predicted heart attack risk. Blood pressure also rises as students approach everyday academic stressors (Conley & Lehman, 2012).

So, are some of us at high risk of stress-related coronary heart disease? To answer this question, the researchers who studied the tax accountants launched a nine-year study of more than 3000 healthy men, aged 35 to 59. The researchers first interviewed each man for 15 minutes, noting his work and eating habits, manner of talking, and other behavior patterns. Those who seemed the most reactive, competitive, hard-driving, impatient, time-conscious, supermotivated, verbally aggressive, and easily angered they called Type A. The roughly equal number who were more easygoing they called Type B. Which group do you suppose turned out to be the most prone to coronary heart disease?

Nine years later, 257 men had suffered heart attacks, and 69 percent of them were Type A. Moreover, not one of the “pure” Type Bs—the most mellow and laid back of their group—had suffered a heart attack.

As often happens in science, this exciting discovery provoked enormous public interest. After that initial honeymoon period, researchers wanted to know more. Was the finding reliable? If so, what was the toxic component of the Type A profile: Time-consciousness? Competitiveness? Anger?

More than 700 studies have now explored possible psychological correlates or predictors of cardiovascular health (Chida & Hamer, 2008; Chida & Steptoe, 2009). These reveal that Type A’s toxic core is negative emotions—especially the anger associated with an aggressively reactive temperament. When we are harassed or challenged, our active sympathetic nervous system redistributes bloodflow to our muscles, pulling it away from our internal organs. One of those organs, the liver, which normally removes cholesterol and fat from the blood, can’t do its job. Type A individuals are more often “combat ready.” Thus, excess cholesterol and fat may continue to circulate in their blood and later get deposited around the heart. Further stress—sometimes conflicts brought on by their own abrasiveness—may trigger altered heart rhythms. In people with weakened hearts, this altered pattern can cause sudden death (Kamarck & Jennings, 1991). Hostility also correlates with other risk factors, such as smoking, drinking, and obesity (Bunde & Suls, 2006). In important ways, people’s minds and hearts interact.

Hundreds of other studies of young and middle-aged men and women have confirmed the finding that people who react with anger over little things are the most coronary-prone. Suppressing negative emotions only heightens the risk (Kupper & Denollet, 2007). One study followed 13,000 middle-aged people for 5 years. Among those with normal blood pressure, people who had scored high on anger were three times more likely to have had heart attacks, even after researchers controlled for smoking and weight (Williams et al., 2000). Another study followed 1055 male medical students over an average of 36 years. Those who had reported being hot tempered were five times more likely to have had a heart attack by age 55 (Chang et al., 2002). Rage “seems to lash back and strike us in the heart muscle” (Spielberger & London, 1982).

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Type D Personality In recent years, another personality type has interested stress and heart disease researchers. Type A individuals direct their negative emotion toward dominating others. People with another personality type—Type D—suppress their negative emotion to avoid social disapproval. The negative emotion these Type D individuals experience during social interactions is mainly distress (Denollet, 2005; Denollet et al., 1996). In one analysis of 12 studies, having a Type D personality significantly increased risk for mortality and nonfatal heart attack (Grande et al., 2012).

Effects of Pessimism and Depression Pessimism seems to be similarly toxic. Laura Kubzansky and her colleagues (2001) studied 1306 initially healthy men who a decade earlier had scored as optimists, pessimists, or neither. Even after other risk factors such as smoking had been ruled out, pessimists were more than twice as likely as optimists to develop heart disease (FIGURE 12.25).

Depression, too, can be lethal. Happy people tend to be healthier and to outlive their unhappy peers (Diener & Chan, 2011; Siahpush et al., 2008). Even a big, happy smile predicts longevity, as researchers discovered when they examined the photographs of 150 Major League Baseball players who had appeared in the 1952 Baseball Register and had died by 2009 (Abel & Kruger, 2010). On average, the nonsmilers had died at 73, compared with an average 80 years for those with a broad, genuine smile. People with broad smiles tend to have extensive social networks, which predict longer life (Hertenstein, 2009).

The accumulated evidence suggests that “depression substantially increases the risk of death, especially death by unnatural causes and cardiovascular disease” (Wulsin et al., 1999). After following 63,469 women over a dozen years, researchers found more than a doubled rate of heart attack death among those who initially scored as depressed (Whang et al., 2009). In the years following a heart attack, people with high scores for depression were four times more likely than their low-scoring counterparts to develop further heart problems (Frasure-Smith & Lesperance, 2005). Depression is disheartening.

Stress and Inflammation Depressed people tend to smoke more and exercise less (Whooley et al., 2008), but stress itself is also disheartening:

As FIGURE 12.26 illustrates, both heart disease and depression may result when chronic stress triggers persistent inflammation (Matthews, 2005; Miller & Blackwell, 2006). After a heart attack, stress and anxiety increase the risk of death or of another attack (Roest et al., 2010). As we have seen, stress disrupts the body’s disease-fighting immune system, enabling the body to focus its energies on fleeing or fighting the threat. Yet stress hormones enhance one immune response, the production of proteins that contribute to inflammation. Thus, people who experience social threats, including children raised in harsh families, are more prone to inflammation responses (Dickerson et al., 2009; Miller & Chen, 2010). Inflammation fights infections; if you cut yourself, inflammation recruits infection-fighting cells. But persistent inflammation can produce problems such as asthma or clogged arteries, and worsen depression. Researchers are now uncovering the molecular mechanisms by which stress, in some people, activates genes that control inflammation (Cole et al., 2010).

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We can view the stress effect on our disease resistance as a price we pay for the benefits of stress (FIGURE 12.27). Stress invigorates our lives by arousing and motivating us. An unstressed life would hardly be challenging or productive.

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Psychological states are physiological events that influence other parts of our physiological system. Just pausing to think about biting into an orange section—the sweet, tangy juice from the pulpy fruit flooding across your tongue—can trigger salivation. As the Indian sage Santi Parva recognized more than 4000 years ago, “Mental disorders arise from physical causes, and likewise physical disorders arise from mental causes.” There is an interplay between our heads and our health. We are biopsychosocial systems.

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