Adjustment Disorders Discussion Paper

5 stress and physical and mental health

learning objectives 5

·  5.1 What is stress?

·  5.2 How does the body respond to stress?

·  5.3 What role does our emotional state play in our physical health?

·  5.4 What mental disorders are explicitly recognized as being triggered by stress?

·  5.5 What are the clinical features of posttraumatic stress disorder?

·  5.6 What are the risk factors for PTSD?

·  5.7 What treatment approaches are used for PTSD?

With its deadlines, interpersonal tensions, financial pressures, and everyday hassles, daily life places many demands on us. We are all exposed to stress, and this exposure affects our physical and our psychological well-being. Sometimes even leisure activities can be stressful. For example, a loss in the Superbowl is followed by an increase in heart attacks and death over the following two weeks in the losing team’s city (Kloner et al.,  2011 ). And watching a stressful soccer match more than doubles the risk of having acute cardiovascular problems (Wilbert-Lampen et al.,  2008 ). How are you affected by stress? Does it make you anxious? Does it give you migraines? Adjustment Disorders Discussion Paper

The field of  health psychology  is concerned with the effects of stress and other psychological factors in the development and maintenance of physical problems. Health psychology is a subspecialty within  behavioral medicine . A behavioral medicine approach to physical illness is concerned with psychological factors that may predispose an individual to medical problems. These may include such factors as stressful life events, certain personality traits, particular coping styles, and lack of social support. Within behavioral medicine there is also a focus on the effects of stress on the body, including the immune, endocrine, gastrointestinal, and cardiovascular systems.

But stress affects the mind as well as the body. As we discussed in  Chapter 3 , the role that stress can play in triggering the onset of mental disorders in vulnerable people is explicitly acknowledged in the diathesis-stress model. Moreover, exposure to extreme and traumatic stress may overwhelm the coping resources of otherwise apparently healthy people, leading to mental disorders such as  posttraumatic stress disorder (PTSD) , as in the following example. Adjustment Disorders Discussion Paper

Posttraumatic Stress in a Military Nurse Jennifer developed PTSD after she served as a nurse in Iraq. During her deployment she worked 12- to 14-hour shifts in 120-degree temperatures. Sleep was hard to come by and disaster was routine. Day in and day out there was a never-ending flow of mangled bodies of young soldiers. Jennifer recalled one especially traumatic event:

·  I was working one evening. We received information that a vehicle, on a routine convoy mission, had been hit by an improvised explosive device (IED). Three wounded men and one dead soldier were on their way to our hospital. Two medics in the back room were processing the dead soldier for Mortuary Affairs. The dead soldier was lying on a cot. The air was strong with the smell of burned flesh. I was staring at the body and trying to grasp what was different about this particular body. After a while I realized. The upper chest and head of the dead soldier was completely missing. We received his head about an hour later. (Based on Feczer & Bjorklund,  2009 ).

In this chapter we consider the role that stress plays in the development of physical and mental disorders. We discuss both physical and mental problems because the mind and the body are powerfully connected and because stress takes its toll on both. Although the problems that are linked to stress are many, we limit our discussion to the most severe stress-related physical and mental disorders. In the physical realm, we focus on heart disease. For mental disorders, we concern ourselves primarily with PTSD.

After a Superbowl loss, heart attacks and death increase in the losing team’s city.

What is Stress?

Life would be very simple if all of our needs were automatically satisfied. In reality, however, many obstacles, both personal and environmental, get in the way. A promising athletic career may be brought to an end by injury; we may have less money than we need; we may be rejected by the person we love. The demands of life require that we adjust. When we experience or perceive challenges to our physical or emotional well-being that exceed our coping resources and abilities, the psychological condition that results is typically referred to as stress (see Shalev,  2009 ). To avoid confusion, we will refer to external demands as  stressors , to the effects they create within the organism as  stress , and to efforts to deal with stress as  coping strategies . It is also important to note that stress is fundamentally an interactive and dynamic construct because it reflects the interaction between the organism and the environment over time (Monroe,  2008 ).

All situations that require adjustment can be regarded as potentially stressful. Prior to the influential work of Canadian physician and endocrinologist Hans Selye ( 1956 ,  1976 ), stress was a term used by engineers. Selye took the word and used it to describe the difficulties and strains experienced by living organisms as they struggled to cope with and adapt to changing environmental conditions. His work provided the foundation for current stress research. Selye also noted that stress could occur not only in negative situations (such as taking an examination) but also in positive situations (such as a wedding). Both kinds of stress can tax a person’s resources and coping skills, although bad stress ( distress ) typically has the potential to do more damage. Stress can also occur in more than one form—not just as a simple catastrophe but also as a continuous force that exceeds the person’s capability of managing it.

Stress and the DSM

The relationship between stress and psychopathology is considered so important that the role of stress is recognized in diagnostic formulations. Nowhere is this more apparent than in the diagnosis of PTSD—a severe disorder that we will discuss later. PTSD was classified as an anxiety disorder in DSM-IV. However, DSM-5 introduced a new diagnostic category called trauma- and stressor related disorders. PTSD is now included there. Other disorders in this new category are adjustment disorder and acute stress disorder. These disorders involve patterns of psychological and behavioral disturbances that occur in response to identifiable stressors. The key differences among them lie not only in the severity of the disturbances but also in the nature of the stressors and the time frame during which the disorders occur (Cardeña et al.,  2003 ). Adjustment Disorders Discussion Paper

Factors Predisposing a Person To Stress

 SHAPE * MERGEFORMAT 

Stress can result from both negative and positive events. Both types of stress can tax a person’s resources and coping skills, although distress (negative stress) typically has the potential to do more damage.

Everyone faces a unique pattern of demands to which he or she must adjust. This is because people perceive and interpret similar situations differently and also because, objectively, no two people are faced with exactly the same pattern of stressors. Some individuals are also more likely to develop long-term problems under stress than others. This may be linked, in part, to coping skills and the presence of particular resources. Children, for example, are particularly vulnerable to severe stressors such as war and terrorism (Petrovic,  2004 ). Research also suggests that adolescents with depressed parents are more sensitive to stressful events; these adolescents are also more likely to have problems with depression themselves after experiencing stressful life events than those who do not have depressed parents (Bouma et al.,  2008 ).

Individual characteristics that have been identified as improving a person’s ability to handle life stress include higher levels of optimism, greater psychological control or mastery, increased self-esteem, and better social support (Declercq et al.,  2007 ; Taylor & Stanton,  2007 ). These stable factors are linked to reduced levels of distress in the face of life events as well as more favorable health outcomes. There is also some evidence from twin studies that differences in coping styles may be linked to underlying genetic differences (Jang et al.,  2007 ).

A major development in stress research was the discovery that a particular form of a particular gene (the 5HTTLPR gene) was linked to how likely it was that people would become depressed in the face of life stress. Caspi and colleagues ( 2003 ) found that people who had two “short” forms of this gene (the s/s genotype) were more likely to develop depression when they experienced four or more stressful life events than were people who had two “long” forms of this gene (the l/l geneotype). Although this specific finding was controversial for a while a recent meta-analysis has provided clear support for the original finding (Karg et al.,  2011 ). More generally, it is now widely accepted that our genetic makeup can render us more or less “stress-sensitive.” Researchers are exploring genes that may play a role in determining how reactive to stress we are (Alexander et al.,  2009 ; Armbruster et al.,  2012 ).

The amount of stress we experience early in life may also make us more sensitive to stress later on (Gillespie & Nemeroff,  2007 ; Lupien et al.,  2009 ). The effects of stress may be cumulative, with each stressful experience serving to make the system more reactive. Evidence from animal studies shows that being exposed to a single stressful experience can enhance responsiveness to stressful events that occur later (Johnson, O’Connor et al.,  2002 ). Rats that were exposed to stressful tail shocks produced more of the stress hormone cortisol when they were later exposed to another stressful experience (being placed on a platform). Other biological changes associated with stress were also more pronounced in these rats. These results suggest that prior stressful experiences may sensitize us biologically, making us more reactive to later stressful experiences. The term  stress tolerance  refers to a person’s ability to withstand stress without becoming seriously impaired.

Stressful experiences may also create a self-perpetuating cycle by changing how we think about, or appraise, the things that happen to us. Studies have shown that stressful situations may be related to or intensified by a person’s cognitions (Nixon & Bryant,  2005 ). This may explain why people with a history of depression tend to experience negative events as more stressful than other people do (Havermans et al.,  2007 ). For example, if you’re feeling depressed or anxious already, you may perceive a friend’s canceling a movie date as an indication that she doesn’t want to spend time with you. Even though the reality may be that a demand in her own life has kept her from keeping your date, when you feel bad you will be much more inclined to come to a negative conclusion about what just happened rather than see the situation in a more balanced or more optimistic way. Can you think of an example in your own life when something like this has happened to you?

Characteristics of Stressors

Why is misplacing our keys so much less stressful than being in an unhappy marriage or being fired from a job? At some level we all intuitively understand what makes one stressor more serious than another. The key factors involve (1) the severity of the stressor, (2) its chronicity (i.e., how long it lasts), (3) its timing, (4) how closely it affects our own lives, (5) how expected it is, and (6) how controllable it is.

Stressors that involve the more important aspects of a person’s life—such as the death of a loved one, a divorce, a job loss, a serious illness, or negative social exchanges—tend to be highly stressful for most people (Aldwin,  2007 ; Newsom et al.,  2008 ). Furthermore, the longer a stressor operates, the more severe its effects. A person may be frustrated in a boring and unrewarding job from which there is seemingly no escape, suffer for years in an unhappy and conflict-filled marriage, or be severely frustrated by a physical limitation or a long-term health problem. As we have already noted, stressors also often have cumulative effects (Miller,  2007 ). A married couple may endure a long series of difficulties and frustrations, only to divorce after experiencing what might seem to be a minor precipitating stressor. Encountering a number of stressors at the same time also makes a difference. If a man loses his job, learns that his wife is seriously ill, and receives news that his son has been arrested for selling drugs, all at the same time, the resulting stress will be more severe than if these events occurred separately and over an extended period. Symptoms of stress also intensify when a person is more closely involved in an immediately traumatic situation. Learning that the uncle of a close friend was injured in a car accident is not as stressful as being in an accident oneself. Adjustment Disorders Discussion Paper

A devastating house fire is not an event we can anticipate. It is almost impossible to be psychologically prepared to experience a stressor such as this.

Extensive research has shown that events that are unpredictable and unanticipated (and for which no previously developed coping strategies are available) are likely to place a person under severe stress. A devastating house fire and the damage it brings are not occurrences with which anyone has learned to cope. Likewise, recovery from the stress created by major surgery can be improved when a patient is given realistic expectations beforehand; knowing what to expect adds predictability to the situation. In one study, patients who were about to undergo hip replacement surgery watched a 12-minute film the evening before they had the operation. The film described the entire procedure from the patient’s perspective. Compared to controls who did not see the film, patients who saw the video were less anxious on the morning of the surgery, were less anxious after the surgery, and needed less pain medication (Doering et al.,  2000 ). Adjustment Disorders Discussion Paper

Unpredictable and uncontrollable events cause the greatest stress. These people are reacting to the collapse of the World Trade Center towers.

Finally, with an uncontrollable stressor, there is no way to reduce its impact, such as by escape or avoidance. In general, both people and animals are more stressed by unpredictable and uncontrollable stressors than by stressors that are of equal physical magnitude but are either predictable or controllable or both (e.g., Evans & Stecker,  2004 ; Maier & Watkins,  1998 ).

THE EXPERIENCE OF CRISIS

Most of us experience occasional periods of especially acute (sudden and intense) stress. The term  crisis  is used to refer to times when a stressful situation threatens to exceed or exceeds the adaptive capacities of a person or a group. Crises are often especially stressful, because the stressors are so potent that the coping techniques we typically use do not work. Stress can be distinguished from crisis in this way: A traumatic situation or crisis overwhelms a person’s ability to cope, whereas stress does not necessarily overwhelm the person.

Measuring Life Stress

Life changes, even positive ones such as being promoted or getting married, place new demands on us and may therefore be stressful. The stress from life changes can trigger problems, even in disorders, such as bipolar disorder, that have strong biological underpinnings (see Johnson & Miller,  1997 ). The faster life changes occur, the greater the stress that is experienced.

A major focus of research on life changes has concerned the measurement of life stress. Years ago, Holmes and Rahe ( 1967 ) developed the Social Readjustment Rating Scale. This is a self-report checklist of fairly common, stressful life experiences (see also Chung et al.,  2010 ; Cooper & Dewe,  2007 ). Although easy to use, limitations of the checklist method later led to the development of interview-based approaches such as the Life Events and Difficulties Schedule (LEDS; Brown & Harris,  1978 ). One advantage of the LEDS is that it includes an extensive manual that provides rules for rating both acute and chronic forms of stress. The LEDS system also allows raters to consider a person’s unique circumstances when rating each life event. For example, if a woman who is happily married and in good financial circumstances learns that she is going to have a baby, she may experience this news in a way that is quite different from that of an unmarried teenager who is faced with the prospect of having to tell her parents that she is pregnant. Although interview-based approaches are more time consuming and costly to administer, they are considered more reliable and are preferred for research in this area (see Monroe,  2008 ). Adjustment Disorders Discussion Paper

Resilience

After experiencing a potentially traumatic event, some people function well and experience very few symptoms in the following weeks and months. This kind of healthy psychological and physical functioning after a potentially traumatic event is called  resilience . You might be surprised to learn that resilience is not rare. In fact, resilience is the most common reaction following loss or trauma (Bonnano et al.,  2011 ; Quale & Schanke,  2010 ).

But why are some people more resilient than others? Research suggests that there is no single factor that predicts resilience. Rather, resilience is linked to a variety of different characteristics and resources. Factors that increase resilience include being male, being older, and being well educated. Having more economic resources is also beneficial. Some earlier studies suggested that, after the 9/11 attacks in New York, African Americans and members of some Latino groups fared more poorly and showed lower levels of resilience compared to whites. However, race and ethnicity are often confounded with social class. Importantly, when social class is controlled for, statistics show that race and ethnicity are no longer predictive of reduced resiliency.

It also helps to be a positive person. Research shows that people who can still show genuine positive emotions when talking about their recent loss also tend to adjust better after bereavement (see Bonnano et al.,  2011 ). In contrast, having more negative affect, being more inclined to ruminate, and trying to find meaning in what has happened is associated with people doing less well after a traumatic event.

The importance of positive and negative emotions is nicely illustrated in a study of 80 people who were being treated in a specialized rehabilitation hospital (Quale & Schanke,  2010 ). All had multiple traumatic injuries or severe spinal cord injuries, usually caused by accidents. The people who showed most resilience in the months after their injuries were those who, when interviewed shortly after arriving in the hospital, reported that they generally had an optimistic approach to life. In addition to optimism, being generally high on positive affect and low on negative affect also predicted having a more resilient trajectory (as opposed to a distress trajectory) over the period of rehabilitation treatment.

Resilience is the most common response to a potentially traumatic event. Optimism, positive emotions, and having more economic resources are all predictive of resilience.

Finally, it is interesting to note that people who are very self-confident and who view themselves in an overly positive light also tend to cope remarkably well in the face of trauma. Although people with this kind of self-enhancing style are sometimes unpleasant to interact with, such a style may serve them well in times of crisis. For example, in a recent prospective study, Gupta and Bonanno ( 2010 ) showed that college students with this self-enhancing style coped much better over a four-year period than people who did not.

in review

·  • What factors play a role in determining a person’s stress tolerance?

·  • What characteristics of stressors make them more serious and more difficult to adapt to?

·  • Describe two methods that can be used to measure life stress.

·  • What is resilience? Describe three factors that increase resilience and three factors that are associated with reduced resilience.

Stress and the Stress Response

To understand why stress can lead to physical and psychological problems, we need to know what happens to our bodies when we experience stress. Faced with the threat of a perceived stressor, the body undergoes a cascade of biological changes. Two distinct systems are involved here. The  sympathetic-adrenomedullary (SAM) system  (see Gunnar & Quevedo,  2007 ) is designed to mobilize resources and prepare for a fight-or-flight response. The stress response begins in the hypothalamus, which stimulates the sympathetic nervous system (SNS). This, in turn, causes the inner portion of the adrenal glands (the adrenal medulla) to secrete adrenaline (epinephrine) and noradrenaline (norepinephrine). As these circulate through the blood, they cause an increase in heart rate (familiar to all of us). They also get the body to metabolize glucose more rapidly. Adjustment Disorders Discussion Paper

The second system involved in the stress response is called the  hypothalamus-pituitary-adrenal (HPA) system  (which we introduced in  Chapter 3 ; also see  Figure 5.1 ). In addition to stimulating the SNS, the hypothalamus releases a hormone called “corticotrophin-releasing hormone” (or CRH). Traveling in the blood, this hormone stimulates the pituitary gland. The pituitary then secretes adrenocorticotrophic hormone (ACTH). This induces the adrenal cortex (the outer portion of the adrenal gland) to produce the stress hormones called glucocorticoids. In humans, the stress glucocorticoid that is produced is called  cortisol .  Figure 5.1  illustrates this sequence of events.

Cortisol is a good hormone to have around in an emergency. It prepares the body for fight or flight. It also inhibits the innate immune response. This means that if an injury does occur, the body’s inflammatory response to it is delayed. In other words, escape has priority over healing, and tissue repair is secondary to staying alive. This obviously has survival value if you need to run away from a lion that has just mauled you. It also explains why cortisone injections are sometimes used to reduce inflammation in damaged joints.

FIGURE 5.1 The Hypothalamic-Pituitary-Adrenal (HPA) Axis. Prolonged stress leads to secretion of the adrenal hormone cortisol, which elevates blood sugar and increases metabolism. These changes help the body sustain prolonged activity but at the expense of decreased immune system activity.

 Explore the simulation LivePsych! Stress and Immune System on MyPsychLab .

But there is also a downside to cortisol. If the cortisol response is not shut off, cortisol can damage brain cells, especially in the hippocampus (see Sapolsky,  2000 ). At a very fundamental level, stress is bad for your brain. It may even stunt growth (babies who are stressed don’t gain weight in the normal way and “fail to thrive”). Accordingly, the brain has receptors to detect cortisol. When these are activated, they send a feedback message that is designed to dampen the activity of the glands involved in the stress response. But if the stressor remains, the HPA axis stays active and cortisol release continues. Although short-term cortisol production is highly adaptive, a chronically overactive HPA axis, with high levels of circulating cortisol, may be problematic.

Biological Costs of Stress

The biological cost of adapting to stress is called the  allostatic load  (McEwan,  1998 ). When we are relaxed and not experiencing stress, our allostatic load is low. When we are stressed and feeling pressured, our allostatic load will be higher. Although efforts to relate specific stressors to specific medical problems have not generally been successful, stress is becoming a key underlying theme in our understanding of the development and course of virtually all physical illness. Moreover, the focus now is not just on major stressors such as job loss or the death of a loved one, but also on daily stressors such as commuting, unexpected work deadlines, or even computer problems (Almeida,  2005 ). For example, a person with allergies may find his or her resistance further lowered by emotional tension. Similarly, when a virus has already entered a person’s body—as is thought to be the case in multiple sclerosis—emotional stress may interfere with the body’s normal defensive forces or immune system. In like manner, any stress may tend to aggravate and maintain certain disorders, such as migraine headaches (Levor et al.,  1986 ) and rheumatoid arthritis (Affleck et al.,  1994 ; Keefe et al.,  2002 ). Adjustment Disorders Discussion Paper

The Mind–Body Connection

The link between stress and physical illness involves diseases (like colds) that are not directly related to nervous system activity. This suggests that stress may cause an overall vulnerability to disease by compromising immune functioning.  Psychoneuroimmunology  is the study of the interaction between the nervous system and the immune system. Although it was once thought that the immune system was essentially “closed” and responsive only to challenges from foreign substances, we now realize that this is not the case. The nervous system and the immune system communicate in ways that we are now beginning to understand.

Evidence continues to grow that the brain influences the immune system and that the immune system influences the brain. In other words, a person’s behavior and psychological states do indeed affect immune functioning, but the status of the immune system also influences current mental states and behavioral dispositions by affecting the blood levels of circulating neurochemicals; these, in turn, modify brain states. For example, we have already seen that glucocorticoids can cause stress-induced  immunosuppression . In the short term, this can be adaptive (escape first, heal later). However, it makes sense that longer-term stress might create problems for the immune system. To appreciate why this might be, we need to describe briefly the basics of immune functioning.

When we are relaxed and calm, our allostatic load is low.

When our allostatic load is high, we experience the biological signs of stress including high heart rate and increased levels of cortisol.

Understanding the Immune System

The word immune comes from the Latin immunis, which means “exempt.” The  immune system  protects the body from such things as viruses and bacteria. It has been likened to a police force (Kalat,  2001 ). If it is too weak, it cannot function effectively, and the body succumbs to damage from invading viruses and bacteria. Conversely, if the immune system is too strong and unselective, it can turn on the body’s own healthy cells. This is what may happen in the case of autoimmune diseases such as rheumatoid arthritis and lupus. Adjustment Disorders Discussion Paper

The front line of defense in the immune system is the white blood cells. These  leukocytes  (or  lymphocytes ) are produced in the bone marrow and then stored in various places throughout the body, such as the spleen and the lymph nodes. There are two important types of leukocytes. One type, called a  B-cell (because it matures in the bone marrow) produces specific antibodies that are designed to respond to specific antigens.  Antigens  (the word is a contraction of antibody generator) are foreign bodies such as viruses and bacteria, as well as internal invaders such as tumors and cancer cells. The second important type of leukocyte is the  T-cell  (so named because it matures in the thymus, which is an important endocrine gland). When the immune system is stimulated, B-cells and T-cells become activated and multiply rapidly, mounting various forms of counterattack (see  Figure 5.2 ).

FIGURE 5.2 Immune System Responses to a Bacterial Infection .

Source: J. W. Kalat.  2001 . Biological Psychology, 7th ed. Belmont, CA: Wadsworth.

T-cells circulate through the blood and lymph systems in an inactive form. Each T-cell has receptors on its surface that recognize one specific type of antigen. However, the T-cells are unable to recognize antigens by themselves. They become activated when immune cells called macrophages (the word means “big eater”) detect antigens and start to engulf and digest them. To activate the T-cells, the macrophages release a chemical known as interleukin-1. With the help of the macrophages, the T-cells become activated and are able to begin to destroy antigens (Maier et al.,  1994 ).

B-cells are different in structure from T-cells. When a B-cell recognizes an antigen, it begins to divide and to produce antibodies that circulate in the blood. This process is facilitated by cytokines that are released by the T-cells. Production of antibodies takes 5 days or more (Maier et al.,  1994 ). However, the response of the immune system will be much more rapid if the antigen ever appears in the future because the immune system has a “memory” of the invader.

The protective activity of the B- and T-cells is supported and reinforced by other specialized components of the system, most notably natural killer cells, macrophages (which we have already mentioned), and granulocytes. The immune system’s response to antigen invasion is intricately orchestrated, requiring the intact functioning of numerous components.

An important component of the immune system response involves  cytokines . Cytokines are small protein molecules that serve as chemical messengers and allow immune cells to communicate with each other. Interleukin-1, which we have just discussed, is a cytokine. Another cytokine that you may have heard about is interferon, which is given to patients with cancer, multiple sclerosis, and hepatitis C.

Cytokines play an important role in mediating the inflammatory and immune response (see Kronfol & Remick,  2000 , for a review). They can be divided into two main categories: proinflammatory cytokines and anti-inflammatory cytokines. Proinflammatory cytokines such as interleukin-1 (IL-1), IL-6, or tumor necrosis factor help us deal with challenges to our immune system by augmenting the immune response. In contrast, anti-inflammatory cytokines such as IL-4, IL-10, and IL-13 decrease or dampen the response that the immune system makes. Sometimes they accomplish this by blocking the synthesis of other cytokines. Adjustment Disorders Discussion Paper

What makes cytokines especially interesting is that in addition to communicating with the immune system, they also send signals to the brain. Because the brain and the immune system can communicate via the cytokines, we can regard the immune system almost as another sensory organ. Far from being a self-contained system, the immune system can monitor our internal state and send the brain information about infection and injury. The brain can then respond. What this means is that the brain is capable of influencing immune processes. With this in mind, some of the findings discussed in this chapter (the link between depression and heart disease, for example, and the health benefits of optimism and social support) make much more sense. In a very tangible way, what is going on at the level of the brain can affect what is going on with the body, and vice versa.

We also know that IL-1 and other cytokines can stimulate the HPA axis (refer back to  Figure 5.1 ). The resulting increase in cortisol sets off a negative feedback loop that is designed to prevent an excessive or exaggerated immune or inflammatory response. However, if this feedback system fails and is either too sensitive or not sensitive enough, serious disorders such as cancer, infection, or autoimmune diseases can develop. Because the brain is also involved in this feedback loop, emotional factors and psychosocial stresses may tilt the balance in the feedback loop in either a helpful or a detrimental way.

One implication of developments in cytokine research is that disorders of the brain could potentially have “downstream” effects on the immune system. In the opposite direction, problems with the immune system may also lead to some behavioral changes or even to psychiatric problems. For example, when you are ill you sleep more, have a diminished appetite, and have little sexual interest. This is classic sickness behavior. It may also result, at least in part, from the effects of specific cytokines on the brain. When cytokines such as IL-1 or interferon are injected, subjects become lethargic, lose their appetites, and have trouble concentrating, among other problems (Reichenberg et al.,  2001 ). In other words, they have some of the symptoms of depression. And when cancer patients are treated with cytokines such as interferon, they experience both flu-like symptoms and depression, the latter of which is typically treated with paroxetine (Paxil), an antidepressant (Musselman et al.,  2001 ). In short, cytokines may have great potential for helping us understand the links between physical and mental well-being that are at the heart of behavioral medicine.

Stress, Depression, and the Immune System

Did you know that stress slows the healing of wounds by as much as 24 to 40 percent (Kiecolt-Glaser et al.,  2002 )? This is because stress is linked to suppression of the immune system (Segerstrom & Miller,  2004 ). The list of stressors that have been linked to immunosuppression is varied and includes sleep deprivation, marathon running, space flight, being the caregiver for a patient with dementia, and death of a spouse (Cacioppo et al.,  1998 ; Schleifer et al.,  1985 ; Schleifer et al.,  1989 ; Vasiljeva et al.,  1989 ). On the positive side, there is evidence that laughter is associated with enhanced immune functioning (Berk et al.,  1988 ; Lefcourt,  2002 ).

Although short-term stress (such as occurs when we take an examination) compromises the immune system (Glaser et al.,  1985 ; Glaser et al.,  1987 ), it is the more enduring stressors such as unemployment or loss of a spouse that are associated with the most global immunosuppression. This is of particular concern in today’s difficult economic times. People who are unemployed have lower levels of immune functioning than people who are employed. The good news, however, is that immune functioning returns to normal again once people find another job (Cohen et al.,  2007 ). Adjustment Disorders Discussion Paper

Stress causes our immune system to function less efficiently.

Depression is also associated with compromised immune function (Kiecolt-Glaser et al.,  2002 ). Moreover, the relationship between depression and suppression of the immune system is at least partially independent of specific situations or events that may have provoked depressed feelings. In other words, the state of being depressed adds something beyond any negative effects of the stressors precipitating the depressed mood.

research CLOSE-UP: Correlational Research

In contrast to experimental research (which involves manipulating variables in some way and seeing what happens), in correlational research the researcher observes or assesses the characteristics of different groups, learning much about them without manipulating the conditions to which they are exposed.

Although there is a great deal of evidence linking stress to suppression of the immune system, researchers are becoming aware that both chronic stress and depression may also enhance certain immune system responses, although not in a good way (Robles et al.,  2005 ). Chronic stress and depression may trigger the production of proinflammatory cytokines such as interleukin-6 (IL-6). One  correlational research  study showed that women who were caring for a family member with Alzheimer’s disease had higher levels of IL-6 than women who were either anticipating the stress of relocation or who were experiencing neither of these stressors (Lutgendorf et al.,  1999 ). This difference was found even though the women who were caregivers were 6 to 9 years younger than the women in the other two groups and even though IL-6 levels are known to increase with age. Major depression has also been linked to enhanced production of proinflammatory cytokines, including IL-6, but treatment with antidepressant medications can reduce this elevation (Kenis & Maes,  2002 ).

These findings are especially interesting in light of research showing a relationship between IL-6 and aging, as well as to chronic diseases including certain cancers and cardiovascular disease (Papanicolaou et al.,  1998 ). Further evidence that higher levels of IL-6 are bad for health is suggested by their association with being overweight, smoking, and having a sedentary lifestyle (Ferrucci et al.,  1999 ).

One group of investigators has reported that older adults (average age 71 years) who regularly attended church had lower levels of IL-6 and were less likely to die during the course of a 12-year follow-up than those who did not go to church regularly (Lutgendorf et al.,  2004 ). These findings also held when other potential confounding variables such as age, social support, being overweight, having medical problems, and being depressed were also considered. Given all of the findings, it is not hard to see why researchers are becoming excited about the possibility that proinflammatory cytokines like IL-6 could be key mediators in the link between psychosocial factors and disease. Overall, what the research findings suggest is that chronic stress and depression can result in the immune system going out of balance in ways that may compromise health (see Robles et al.,  2005 ). In short, the potential for psychological factors to influence our health and for our health to affect our psychological well-being is becoming ever more apparent. Adjustment Disorders Discussion Paper

in review

·  • Describe the biological changes that occur when we are under stress.

·  • What is cortisol? Is cortisol beneficial or harmful?

·  • What is meant by the term allostatic load?

·  • Describe the relationship between stress and the immune system.