Hockenbury Discovering Psychology 5th txtbk

Physical Effects of Stress507PsychoneuroimmunologyUntil the 1970s, the immune system was thought to be completely independentof other body systems, including the nervous and endocrine systems. Thus, mostscientists believed that psychological processes could not influence the immunesystem response.That notion was challenged in the mid-1970s, when psychologist RobertAder teamed up with immunologist Nicholas Cohen. Ader (1993) recalls, “Asa psychologist, I was not aware of the general position of immunology thatthere were no connections between the brain and the immune system.” ButAder and Cohen showed that the immune system response in rats could beclassically conditioned (see Chapter 5). After repeatedly pairing flavoredwater with a drug that suppressed immune system functioning, Ader and Cohen(1975) demonstrated that the flavored water alone suppressed the immune system.Ader and Cohen’s research helped establish a new interdisciplinary field calledpsychoneuroimmunology. Psychoneuroimmunology is the scientific study of theconnections among psychological processes (psycho-), the nervous system (-neuro-),and the immune system (-immunology).Today, it is known that there are many interconnections among the immune system,the endocrine system, and the nervous system, including the brain (Ader,2001; Segerstrom & Miller, 2004). First, the central nervous system and the immunesystem are directly linked via sympathetic nervous system fibers, which influencethe production and functioning of lymphocytes.Second, the surfaces of lymphocytes contain receptor sites for neurotransmittersand hormones, including catecholamines and cortisol. Thus, rather than operatingindependently, the activities of lymphocytes and the immune system are directly influencedby neurotransmitters, hormones, and other chemical messengers from thenervous and endocrine systems.Third, psychoneuroimmunologists have discovered that lymphocytes themselvesproduce neurotransmitters and hormones. These neurotransmitters and hormones,in turn, influence the nervous and endocrine systems. In other words, there is ongoinginteraction and communication among the nervous system, the endocrinesystem, and the immune system. Each system influences and is influenced by theother systems (Kiecolt-Glaser, 2009).Stressors That Can Influence the Immune SystemWhen researchers began studying how stress affects the immune system, they initiallyfocused on extremely stressful events (see Kiecolt-Glaser & Glaser, 1993). Forexample, researchers looked at how the immune system was affected by such intensestressors as the reentry and splashdown of returning Skylab astronauts, being forcedto stay awake for days, and fasting for a week (Kimzey, 1975; Leach & Rambaut,1974; Palmblad & others, 1979). Each of these highly stressful events, it turnedout, was associated with reduced immune system functioning.Could immune system functioning also be affected by more common negative lifeevents, such as the death of a spouse, divorce, or marital separation? In a word, yes. Researchersconsistently found that the stress caused by the end or disruption of importantinterpersonal relationships impairs immune function, putting people at greater riskfor health problems (Kiecolt-Glaser, 1999; Kiecolt-Glaser & Newton, 2001). Andperhaps not surprisingly, chronic stressors that continue for years, such as caringfor a family member with Alzheimer’s disease, also diminish immune system functioning(Cass, 2006; Robles & others, 2005).What about the ordinary stressors of life, such as the pressure of exams? Dothey affect immune system functioning? Since the 1980s, psychologist JaniceKiecolt-Glaser and her husband, immunologist Ronald Glaser, have collectedimmunological and psychological data from medical students. Severaltimes each academic year, the medical students face three-day examinationperiods. Kiecolt-Glaser and Glaser have consistently found that eventhe commonplace stress of exams can adversely affect the immune system(Glaser & Kiecolt-Glaser, 2005; Kiecolt-Glaser & Glaser, 1991, 1993).Conditioning the Immune SystemPsychologist Robert Ader (left) teamedwith immunologist Nicholas Cohen (right)and demonstrated that immune systemresponses could be classically conditioned.Ader and Cohen’s groundbreakingresearch helped lead to the new field ofpsychoneuroimmunology—the study ofthe connections among psychologicalprocesses, the nervous system, and theimmune system.Ron Glaser and Janice Kiecolt-GlaserTwo of the leading researchers in psycho -neuroimmunology are psychologist JaniceKiecolt-Glaser and her husband, immunologistRon Glaser. Their research has shownthat the effectiveness of the immunesystem can be lowered by many commonstressors—from marital arguments tocaring for sick relatives (see Glaser &Kiecolt-Glaser, 2005).