Stress, Health & Well-being Chapter 4 PDF

@ 2012 Wadsworth, Cengage Learning  Topics 1. Illness 2. Research Strategies for Examining Stress and Illness 3. The Life Events Model of Stress and Illness 4. Daily Hassles Model 5. Linking Stress, Illness,...

@ 2012 Wadsworth, Cengage Learning  Topics 1. Illness 2. Research Strategies for Examining Stress and Illness 3. The Life Events Model of Stress and Illness 4. Daily Hassles Model 5. Linking Stress, Illness, and the Immune System 6. Strengthening the Protective and Immune Systems @ 2012 Wadsworth, Cengage Learning  ILLNESS @ 2012 Wadsworth, Cengage Learning  Illness  Infection refers to an invasion of the body by a harmful micro- organism that create a pathological condition in the body.  This pathological condition had recognizable signs and symptoms – referred to as disease (e.g., the disease called the cold).  Disease can be caused by a virus, genetic factors, or environmental conditions. @ 2012 Wadsworth, Cengage Learning  Illness (cont’d.)  Illness/sickness (sickness is a synonym for illness) is the unhealthy state caused by the disease.  The immune system is the body’s defense against infections.  The Sick role involves illness behaviour: people evaluate symptoms, seek medical care and look for support and empathy from others when they are feeling ill. @ 2012 Wadsworth, Cengage Learning  Illness (cont’d.)  It is reinforced when the increased attention, care or relief from duties are found rewarding.  These rewards from being ill are called secondary gains.  These secondary gains are some of the few positive aspects that come with illness. @ 2012 Wadsworth, Cengage Learning  THE LIFE EVENTS MODEL OF STRESS AND ILLNESS @ 2012 Wadsworth, Cengage Learning  The Life Events Model of Stress and Illness  Holmes and Rahe (1967) created an instrument called the Social Readjustment Rating Scale (SRRS) to determine if there is a predicted relationship between stress and illness in humans.  The SRRS conceptualizes stressors as positive or negative life events that require adaptation or adjustment.  The Social Readjustment Rating Scale (SRRS) uses life change units (LCU) (e.g., the death of a spouse) to categorize different events on the scale. @ 2012 Wadsworth, Cengage Learning  The Life Events Model of Stress and Illness  Criticisms of the SRRS led to dozens of other similar scales being developed.  Problems with the stressful life events (SLE) model:  Most studies are based on retrospective self- reports.  Some items on checklists overlap with illnesses.  Effects of negative affectivity/neuroticism levels may influence responses. @ 2012 Wadsworth, Cengage Learning  The Life Events Model of Stress and Illness (cont’d.)  Methodological problems have made it difficult to establish firm and consistent relationships between life changes and illness.  More objective measures such as blood tests are used in collaboration.  The concept of negative life stress events seems to be valid with regard to illness. @ 2012 Wadsworth, Cengage Learning  The Life Events Model of Stress and Illness (cont’d.)  Bedford College Life Events and Difficulties Schedule (LEDS): generally used with clinical populations (i.e., clinical depression).  Uses a semi-structured interview and a panel of trained raters rather than a checklist.  It examines the potential long-term threat of an event in the context in which it occurs. @ 2012 Wadsworth, Cengage Learning  The Life Events Model of Stress and Illness (cont’d.) Disadvantages:  Requires training in administering and scoring.  A panel must analyze and arrive at a consensus.  It is expensive and time consuming. @ 2012 Wadsworth, Cengage Learning  DAILY HASSLES MODEL @ 2012 Wadsworth, Cengage Learning  Daily Hassles Model  Research by Lazarus and colleagues showed that hassles (e.g., waiting in a cue, traffic jams, noise) played more of a role in illness than life change events.  This model suffers from similar methodological problems as the life events model.  For example, neuroticism can influence self-report of hassles. @ 2012 Wadsworth, Cengage Learning  Daily Hassles Model  Today, researchers use hassles scales to measure the effects of daily stressors on a wide variety of health conditions including asthma, fibromyalgia, and tension-type headache to name a few.  SLE and hassles measures are sometimes combined to study reports of health problems. @ 2012 Wadsworth, Cengage Learning  LINKING STRESS, ILLNESS, AND THE IMMUNE SYSTEM @ 2012 Wadsworth, Cengage Learning  Linking Stress, Illness, and the Immune System  Solomon and Moos (1964) were the first to publish the term psychoneuroimmunology (PNI) to refer to the study of the relationship among the psychological, neurological, and immunological interactions.  Pelletier and Herzing (1988, p. 29) defined the then emerging interdisciplinary field of PNI as: @ 2012 Wadsworth, Cengage Learning  Linking Stress, Illness, and the Immune System  “The study of the intricate interaction of consciousness (psycho), brain and central nervous system (neuro), and the body’s defence against external infection and internal aberrant cell division (immunology).”  As suggested by Pelletier (1977), stress plays a role in 50% to 80% of all illnesses and diseases.  PNI now an established field backed up by hundreds of studies. @ 2012 Wadsworth, Cengage Learning  The Human Immune System  The human immune system is designed to protects us from harmful exogenous (bacteria, fungi, viruses) and endogenous (own cells) threats.  These threats to our health are referred to as antigens.  Several layers of defence comprise our protective and immune systems.  Skin and mucous membranes block bacteria; those that enter the skin are attacked by leukocytes. @ 2012 Wadsworth, Cengage Learning  The Human Immune System  These first lines of defence consisting of our outer barriers such as the skin and early defenders are layers of the innate protective (immune) system.  Its members are on constant patrol against threats.  Agents of this innate immune system, also known as the natural immune system, have no memory of previous invaders and mount the same intensity of response each time they are threatened. @ 2012 Wadsworth, Cengage Learning  The Human Immune System @ 2012 Wadsworth, Cengage Learning  The Human Immune System  This innate system contrasts with members of the adaptive immune system, also known as the acquired or specific immune system, that remembers past invaders and can mount a vigorous response against specifically remembered offenders.  Because the adaptive immune system takes 4 to 5 days to be activated against a novel invader, the innate immune system must defend us indiscriminately against threatening antigens in the meantime. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Once engaged, however, the adaptive immune system is very effective at targeting and neutralizing the remaining invaders.  Because it remembers the offenders, if they breach the system a second time, the members of the adaptive immune system can quickly neutralize the invader.  Granulocytes, Monocytes, and Lymphocytes @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  The innate immune system consists of phagocytic cells, natural killer (NK) cells, and various enzymes and serum proteins that are involved in the inflammation process.  Inflammation is characterized by heat, redness, pain and swelling in response to damaged tissue or infection. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Our damaged cells and certain white blood cells release chemicals that call more white blood cells to the site.  The first battle responders tend to be neutrophils and some monocytes.  Neutrophils are the most common white blood cells (i.e., leukocytes), constituting over 50% of the total number. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  They are granular cells (i.e., cells with granules that contain digestive enzymes) called granulocytes that literally eat the antigens they attack.  Cells like neutrophils that eat the antigens they attack are called phagocytes (phagos is Greek for “eat”).  Phagocytes are like Pac Men from the vintage video game gobbling up any antigens they encounter. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Other white blood cell granulocytes include eosinophils and basophils. They are present in small numbers and are associated with inflammatory and allergic responses as well as other functions.  Monocytes are mononuclear phagocytes (Pac Men) that become enlarged upon leaving the bloodstream and entering bodily tissue to then become macrophages (bigger Pac Men). @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Another very important defender against the bad characters are the natural killer (NK) cells, which are lymphocytic cells programmed to recognize other cells that are “non-self” such as tumour cells and cells infected with viruses and to release cytotoxic (poisonous to the cell) chemicals that destroy these cells.  Besides the NK cells, other lymphocytic cells include the T cells and B cells. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Thus, T cells, B cells, and NK cells are referred to as lymphocytes.  The thymus, develops mature T cells (“T” for thymus cells) from other immature bone marrow lymphoid stem cells.  T cells include T-helper cells and T-cytotoxic cells. One variety of T-helper cells directs white blood cells to carry out cellular-mediated immunity, whereas another type of T-helper cells partners with B cells to produce humoral immunity. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  T-helper cells are immune cells that act to direct and amplify the immune response through the use of chemical messengers. They have no ability to engage in phagocytic or cytotoxic actions but can direct other cells to do so.  A different type of T cell, the T-cytotoxic cell, does engage directly in the fight because like the NK cell, it is “licensed to kill.”  All T cells contain receptors that recognize the targeted antigen, thus making them part of the adaptive immune system. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  T-helper cells have a molecule known as CD4 on their surface that enables them to respond to the targeted antigen.  It is important to note that, in a reverse of the normal process, the human immunodeficiency virus (HIV) attacks the CD4 T cells, which can then lead to an eventual compromise of the immune system against opportunistic infections. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  The third category of lymphocytes, the B cells (“B” for bone marrow cells), produce antibodies called immunoglobulins (Ig’s), which are soluble proteins that circulate in the bloodstream.  These antibodies bind to viruses, rendering them incapable of invading the body’s own cells. They may also neutralize targeted bacterial toxins.  There are five kinds of antibodies: IgA, IgE, IgM, IgG, and IgD. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Cellular-Mediated Immunity (Th1) and Humoral Immunity (Th2) Strategies  The human immune system employs two major strategies, which can be called the one-two punch of cellular immunity and humoral immunity.  The first punch, cellular-mediated immunity involves the NK cells, granulocytes (e.g., neutrophils), macrophages, and T cells quickly localizing to the site of injury or infection. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  And in the process of inflammation either engulfing (phagocytosing—the Pac Man strategy) damaged endogenous cells along with invading exogenous antigens or releasing toxic substances (e.g., poison dart strategy) to harm them.  This type of immunity is governed by a certain type of T cell known as a Type 1 T-helper (Th1) cell.  The second punch of the immune system’s one- two punch, is known as humoral immunity. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  The cells of this system are tailor made to have specific receptor sites that fit the molecular shape of the antigen.  Therefore, these can only attack one specific type of invader. This type of immunity is most closely associated with the B cells.  The B cells, antibodies, and a different type of T- helper cell, form the primary components of the adaptive immune system. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  Activating the humoral immunity strategy involves the Type 2 T-helper cells (Th2) partnering with B cells to stimulate antibody production.  As discussed previously, this is a much slower process than cellular-mediated immunity, sometimes taking up to 7 days to reach full antibody immunity.  Th1 and Th2 cells inhibit each other’s actions so that by the time the B cells are in full action the Th1 activities should be dampened. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.)  A dysregulated immune system may involve chronic inflammation or autoimmune activity if the Th1 : Th2 ratio is chronically imbalanced. Therefore, a homeostatically balanced Th1/Th2 system is desired for good health. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.): Inflammation process @ 2012 Wadsworth, Cengage Learning  Figure 4.3:Action of Cytotoxic T Cells on a Targeted Cell. Like the James Bond-style NK cells of the innate immune system, these adaptive immune system 008s are “licensed to kill.” SOURCE: Guyton & Hall (2006), Medical Physiology, 11th ed., p. 448, Figure 34.8, Philadelphia: Elsevier Saunders. Reprinted with permission from Elsevier. @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.) @ 2012 Wadsworth, Cengage Learning  The Human Immune System (cont’d.) @ 2012 Wadsworth, Cengage Learning  The Immune System and Acute Stressors  As you will recall from Chapter 3, during the fight-or- flight response, the sympathetic-adrenal medulla (SAM) axis and the hypothalamic-pituitary-adrenal (HPA) axis are activated, resulting in the release of catecholamines and glucocorticoids.  Catecholamines, especially norepinephrine, temporarily boost immunological activity.  This activates leukocytes, which enter the blood stream.  NK cell numbers rise dramatically, and the natural immune system prepares for possible injury or infection. @ 2012 Wadsworth, Cengage Learning  The Immune System and Acute Stressors (cont’d)  Neuropeptides (such as endorphins) released during exercise enhance the immune system’s response.  As stressors become chronic (longer lasting), the body switches from the cellular-mediated immune system to the humoral immune system.  With sufficient time of exposure to the stressors, there is suppression of both cellular and humoral immunity. @ 2012 Wadsworth, Cengage Learning  The Immune System and Acute Stressors (cont’d)  Chronic stressors have broad immunosuppressive effects.  It decreases the number of T-cells. @ 2012 Wadsworth, Cengage Learning  The Immune System and Chronic Stressors  Chronic stressors, unlike acute stressors, generally have broad immunosuppressive effects.  Immune dysregulation refers to the overreacting of the immune system, which can result in allergies, arthritis, etc., and the underreacting of the immune system that can cause cancer and cold/flu outbreaks. @ 2012 Wadsworth, Cengage Learning  The Immune System and Chronic Stressors (cont’d.)  Both types of reactions can occur simultaneously. For example, a person with a suppressed immune system to a cold virus and who is chronically stressed can succumb to the illness of the common cold while also experiencing a hay fever overreaction to pollen.  During chronic stress, the hormones glucocorticoids and cortisol are elevated, which contribute to immunosuppression. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  Many studies have been done to examine the effects of stressors on suppression of the immune system.  Categories of stress-related immuno- suppressive studies:  Exam stressors include the time leading up to the exams. Students have higher levels of cortisol, which suppress the immune system. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  Large-scale disasters can be a source of chronic and intense stress.  The suppression of their immune systems, include lower levels of T-cells, B-cells and NK cells as well as a higher number of herpes simplex virus.  Chronic stress of long-term caregiving of loved ones with Dementia: They have higher levels of stress hormones and lower levels of antibodies. Altered T-cell function and accelerated immune cell ageing. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  Not only was the experience stressful, but it also resulted in immunosuppression.  A recent study found evidence that the chronic stress of giving long-term care to patients with Alzheimer’s disease was “associated with altered T cell function and accelerated immune cell ageing as suggested by excessive telomere loss”  Loss and bereavement: The loss of a spouse to separation, divorce, or more painfully to death is a very stressful event. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  Separated and divorced men reported more distress, loneliness and recent illnesses.  Bereavement studies showed a decrease in NK cytotoxicity.  The NK cells of the subjects had decreased levels of effectiveness, which the authors believed was due to an increase in cortisol production in the bereaved. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  Viral challenges: For chronic infections that have periods of dormancy followed by active phases (e.g., herpes simplex virus [HSV] and Ebstein-Bar virus [EBV]), the presence of an increased titer of blood antibody levels for the virus suggests an immune response deficiency.  This is counterintuitive because we are inclined to think that the higher level equals a more robust immune response. @ 2012 Wadsworth, Cengage Learning  Stress and Immunosuppression  However, in the case of these viruses, the higher levels represent a failure of the innate immune system to suppress the viral activity, thus requiring more B lymphocytes to respond.  Therefore, higher antibody levels mean a weaker immune system.  In the case of viral inoculation, however, we can draw an opposite conclusion; that is, the more robust the anti-body response, the stronger the immune system. @ 2012 Wadsworth, Cengage Learning  STRENGTHENING THE PROTECTIVE AND IMMUNE SYSTEMS @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune Systems  Behavioural strategies for strengthening the immune system:  Wash hands:  The skin is our outer protective layer that gives us a first line of immune defence against infectious agents.  Hand washing serves to remove harmful pathogens before they get into your body through self-infecting the nose, eyes, mouth or other open areas. @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune Systems  Get immunized:  Most of the available immunizations give protection against harmful pathogens.  Get sufficient sleep:  Evidence is mounting that one of the restorative functions of sleep is to regulate the immune system.  Normal sleep consists of increases in NK activity and a shift toward Th1/Th2 cytokine production. @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune Systems  Thus, good quality sleep is involved in maintaining immune competency.  Exercise:  Exercise seems to reduce inflammation and enhance macrophage and NK function.  Regular moderate exercise (30- to 45-minute brisk walks) seems to be the most effective behavioural strategy for boosting the immune system. Too much exercise, however, can temporarily suppress immune function. @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune System  Eat healthy:  The idea is to give your body the nutrition it needs to maintain and repair immune system cells.  Foods that are high in antioxidants help to neutralize free radicals that can damage these and other cells in the body.  Other foods, such as those high in omega-3 fatty acids, appear to have anti-inflammatory properties.  Foods rich in zinc also are beneficial to the immune system. @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune System  Seek treatment for clinical depression:  It is now well documented that major depressive disorder is associated with many immunological changes.  There is immunosuppression leading to potential infectious diseases as well as immune system inflammation leading to potential autoimmune disorders, cardiovascular disease, cancer, or more depression. @ 2012 Wadsworth, Cengage Learning  Strengthening the Protective and Immune System  Avoid known immune system suppressors: Another effective strategy for maintaining a healthy immune system is to avoid known immune system suppressors like cigarette smoke and excessive alcohol intake.  NK cell activity, antibody responses, and functional capacity of leukocytes are all reduced in smokers.  Alcoholics appear to have suppressed immune systems reflected by their higher rates of bacterial and viral infections. @ 2012 Wadsworth, Cengage Learning  Summary  System of organs, tissues, and cells designed to protect the body against infections is referred to as the immune system.  PNI is the study of the relationship between the psychological, neurological, and immunological interactions.  Human immune system is divided into innate and adaptive immune systems. @ 2012 Wadsworth, Cengage Learning  Summary (cont’d.)  Cellular mediated immunity and humoral immunity ratio should be balanced.  Acute stressors can mobilize immune response, but chronic stressors broadly suppress it.  Several recommendations exist for strengthening the immune system. @ 2012 Wadsworth, Cengage Learning