/Physiology, Disease Process And The Mind

Physiology, Disease Process And The Mind

Is illness a purely physical condition?  Does a person’s mind play a role in becoming ill and getting well? People have wondered about these questions for thousands of years, and the answers they have arrived at have changed over time.


Although we do not know for certain, it appears that the best-educated people thousands of years ago believed physical and mental illness were caused by mystical forces, such as evil spirits.


The philosophers of ancient Greece produced the earliest written ideas about  physiology, disease processes, and the mind  between  500 and  300 B.C. Hippocrates, often called ‘‘the Father of Medicine,’’ proposed a humoral theory of illness. According to this theory, the body contains four fluids called humor (in biology, the term humor refers to any plant or animal fluid). When the mixture of these humor is harmonious or balanced, we are in a state of health. The disease occurs when the mixture is faulty.

Greek philosophers, especially  Plato,  were among the first  to propose that the mind and the body are separate entities. The mind was considered to have little or no relationship to the body and its state of health. This remained the dominant view of writers and philosophers for more  than a thousand years, and the body  and the  mind  are  conceptually separate  today.  The body refers to our physical being, including our skin, muscles, bones, heart and brain.  The mind refers to an abstract process that includes our thoughts, perceptions and feelings. Although we can separate the mind and body conceptually, an important issue is whether they function independently.  The question of  their  relationship  is called the mind/body problem.


After the collapse of the Roman Empire in the 5th century A.D., much of the  Western world  was in disarray.  The advancement of knowledge and culture slowed sharply in Europe and remained stunted during the Middle Ages, which lasted almost a thousand years. Sickness was seen as God’s punishment for doing  evil things.  As a result,  the  Church  came  to  control  the practice  of medicine,  and  priests  became  increasingly involved in treating the ill, often by torturing the body to drive out evil spirits. It was  not  until  the  13th  century  that  new  ideas about  the  mind/body  problem  began  to  emerge.  The Italian philosopher St.  Thomas  Aquinas  rejected   the view that the mind and body are separate and saw them as interrelated. Although his position did not have as great an impact as others had had, it renewed interest in the issue and influenced later philosophers.


The word renaissance means rebirth—a fitting name for the 14th and 15th centuries. During this period  in history, Europe  saw a rebirth  of inquiry,  culture,  and  politics. Scholars became more ‘‘human-centered’’ than ‘‘God centered’’  in their  search  for truth  and  ‘‘believed that truth  can be seen  in many ways, from many individual perspectives’’. These ideas set the stage for  important changes   in  philosophy once  the scientific revolution began after 1600.

The 17th-century French philosopher and mathematician   Rene´ Descartes   probably   had   the   greatest influence  on  scientific  thought of any  philosopher in history. Like the Greeks, he regarded the  mind  and  body  as  separate entities, but he introduced three important innovations. First, he conceived of the body as a machine and described the mechanics  of how action  and  sensation occurred.  Second, he proposed that the mind and body, although separate, could communicate through the pineal gland, an  organ  in the  brain. Third, he believed that  animals  have no soul and that  the soul in humans leaves the body at death .

In the 18th and 19th centuries, knowledge in science and  medicine  grew quickly, helped  greatly by improvements   in  the  microscope  and  the  use  of  dissection in  autopsies.  Once  scientists  learned   the   basics   of how the body functioned  and discovered that micro- organisms   cause   certain   diseases,  they  rejected   the humoral  theory  of illness  and  proposed new theories.

The field of surgery flourished after antiseptic techniques and anesthesia were introduced in the mid-19th century. Before  then,  hospitals were  ‘‘notorious places,  more likely to spread  diseases than  cure them’’. Over time, the reputation of physicians and hospitals began to improve, and people’s trust in the ability of doctors  to heal increased.

These   advances,    coupled    with   the   continuing belief  that  the  mind  and  body  are  separate, laid  the foundation for a  new  approach, or  ‘‘model,’’ for conceptualizing  health  and  illness.  This approach called the biomedical model proposes that  all diseases or physical  disorders  can  be  explained   by  disturbances in physiological processes, which result from injury, biochemical  imbalances, bacterial or viral infection, and the like.  The  biomedical  model   assumes  that   disease is  an  affliction  of the  body  and  is  separate from the psychological  and  social  processes of the  mind.  This viewpoint became widely accepted during the 19th and 20th centuries and still represents the dominant view in medicine today.


The idea that medicine and psychology are somehow connected has a long history, dating back at least to ancient Greece.  It became somewhat more formalized early in the 20th century in the work of Sigmund Freud, who was trained as a physician.  He noticed that some patients showed physical symptoms with no detectable organic disorder. Using his psychoanalytic theory, Freud proposed that these symptoms were ‘‘converted’’ from unconscious emotional conflicts. He called this condition conversion hysteria. Symptoms like these occur less often in urban than in backwoods areas,  perhaps because urbanites realize that medical  tests can generally determine if an organic disorder  exists. The need to understand conditions such as  conversion hysteria led to the development of psychosomatic medicine,  the first field dedicated to studying  the interplay  between emotional life and bodily processes.

Psychosomatic Medicine

The field called psychosomatic medicine was formed in the 1930s and began publishing  the journal Psychosomatic Medicine. Its founders were mainly trained  in medicine,  and  their  leaders  included psychoanalysts and  psychiatrists. The field was soon organized as a society now called the American Psychosomatic Society.

The term  psychosomatic  does  not  mean  a  person’s symptoms  are ‘‘imaginary’’; it means  that  the mind and body  are  both  involved.  Early  research   in  psychosomatic  medicine  focused  on  psychoanalytic  interpretations for specific, real health  problems, including ulcers, high blood  pressure, asthma, migraine  headaches, and rheumatoid arthritis.  For example, Alexander (1950) described the case of a 23-year-old man with a bleeding ulcer and proposed that the man’s relationship with his mother created feelings of insecurity and dependency that  caused   the  ulcer.  The  man’s  stomach  problems later decreased, presumably  because he overcame these feelings through  therapy. Over the years, the field’s approaches and  theories evolved. It is currently a broader  field concerned  with interrelationships among psychological and social factors, biological and physiological  functions,  and the  development and course of illness.

Health psychology,  a field that  is principally within the discipline of psychology.


  • To promote and maintain  health. Health psychologists study such   topics   as  why  people   do  and   do  not   smoke cigarettes, exercise,  drink  alcohol,  and  eat  particular diets.   As  a  result,   these   professionals  can  help  in the  design  of school  health  education programs  and media  campaigns to encourage  healthful  lifestyles and behaviors.
  • To prevent  and treat illness. Psychological  principles  have been applied effectively in preventing illness, such as in reducing  high blood  pressure. For people  who become seriously ill, psychologists with clinical training can help them  adjust  to  their  current  condition, rehabilitation program, and future prospects, such as reduced work or sexual activity.
  • To identify  the causes and diagnostic  correlates of health, illness, and related dysfunction. Health psychologists study the causes of disease;   the  research   we saw  earlier  showing  the importance of personality  factors  in the  development of illness  is an example  of the  work toward  this  goal. Psychologists also study physiological and perceptual processes, which affect people’s  experience  of physical symptoms.
  • To analyze  and improve  health care systems  and health policy.


Health  psychologists contribute  toward  this  goal  by studying  and  advising  medical  professionals on  ways by  which  characteristics  or  functions   of  hospitals, nursing  homes,  medical  personnel, and  medical  costs affect patients and their likelihood of following medical advice.


Biopsychosocial Model

In 1977, George Engel at the University of Rochester published a seminal paper that described the biopsychosocial model of disease, which stressed an integrated systems approach to human behavior and disease. The biopsychosocial model is derived from general systems theory. The biological system emphasizes the anatomical, structural, and molecular substrate of disease and its effects on the patient’s biological functioning; the psychological system emphasizes the effects of psychodynamic factors, motivation, and personality on the experience of illness and the reaction to it; and the social system emphasizes cultural, environmental, and familial influences on the expression and the experience of illness. Engel postulated that each system affects, and is affected by, every other system. Engel’s model does not assert that medical illness is a direct result of a person’s psychological or sociocultural makeup but, rather, encourages a comprehensive understanding of disease and treatment.

A dramatic example of Engel’s conception of the biopsychosocial model was a 1971 study of the relation between sudden death and psychological factors. After investigating 170 sudden deaths over about 6 years, he observed that serious illness or even death can be associated with psychological stress or trauma. Among the potential triggering events Engel listed are the following: the death of a close friend, grief, anniversary reactions, loss of self-esteem, personal danger or threat and the letdown after the threat has passed, and reunion or triumphs.


The Role of Biological  Factors

What is included  in the  term biological factors?  This term includes the genetic materials and processes by which we inherit characteristics from our parents. It also includes the  function  and  structure  of the  person’s  physiology. For example,  does  the  body contain  structural defects, such as a malformed heart valve or damage in the brain, that  impair  the  operation of these  organs?  Does  the body respond effectively in protecting  itself, such as by fighting infection?  Does the  body overreact  sometimes in the protective  function,  as happens in many allergic reactions  to   harmless  substances,  such   as   pollen or dust?

The body is made up of enormously complex physical systems.  For instance, it has organs, bones,  and nerves, and these are composed of tissues, which in turn consist of cells, molecules,  and  atoms.  The efficient, effective, and healthful  functioning  of these  systems  depends on the  way these  components operate and  interact  with each other.

The Role of Psychological Factors

When we discussed the role of lifestyle and personality in health and illness earlier, we were describing behavior and mental processes. Behavior and mental processes are the focus of psychology, and they involve cognition, emotion, and motivation.

Cognition is a mental activity that encompasses perceiving, learning, remembering, thinking,  interpreting, believing, and problem-solving. How do these cognitive factors affect health and illness?  Suppose,  for instance, you strongly believe, ‘‘Life is not worth living without the things  I enjoy.’’ If you enjoy smoking cigarettes, would you quit to reduce your risk of getting cancer  or heart disease?  Probably not. Or suppose you develop a pain in your abdomen and you remember having had a similar symptom in the past that disappeared in a couple of days. Would you seek treatment? Again, probably not. These examples are just two of the countless ways cognition plays a role in health and illness.

Emotion is  a  subjective  feeling  that  affects  and  is affected  by  our  thoughts,  behavior,   and   physiology. Some  emotions are  positive  or  pleasant, such  as  joy and  affection,  and  others  are  negative,  such  as  anger, fear, and sadness. Emotions relate to health  and illness in many ways. For instance, people  whose emotions are relatively positive are less disease-prone and more likely to take good care of their health  and to recover quickly from  an  illness  than  are  people  whose  emotions are relatively  negative.  We considered these  relationships when  we discussed the  role  of personality in  illness. Emotions can also  be important in people’s  decisions about  seeking  treatment. People  who are frightened  of doctors  and dentists may avoid getting  the health  care they need.

Motivation is the process  within individuals  that gets them  to  start  some  activity, choose  its  direction,  and persist  in it. A person  who is motivated to feel and look better   might  begin  an  exercise  program,  choose   the goals to be reached,  and stick with it. Many people  are motivated to do what important people in their lives want them to do. Parents who quit smoking because their child pleads with them to protect their health are an example.

The Role of Social Factors

People  live in  a  social  world.  We have  relationships with individual  people—a  family member,  a friend,  or an acquaintance—and with groups.  As we interact  with people,  we affect them, and they affect us. For example, adolescents often start  smoking cigarettes and drinking alcohol as a result of peer pressure. They want very much  to be popular  and  to look ‘‘cool’’  or  ‘‘tough’’ to  schoolmates and  others.   These social processes provide clear and powerful motivational forces. But our social world is larger than just the people we know or meet.

On a fairly broad level, our society affects the health of individuals by promoting certain values of our culture, such as that being fit and healthy is good. The mass media—television, newspapers, and so on—often reflect these values by setting good examples and urging us to eat well, not to use drugs, and not to drink and drive. The media can do much to promote health, but sometimes they encourage unhealthful behavior, such as when children see jazzy TV  commercials for sweet,  nutrient-poor foods.  Can individuals affect society’s values?  Yes, by writing our opinions to the mass media and lawmakers,  selecting which television shows and movies to watch, and buying healthful products, for example.

Our  community consists  of  individuals   who  live fairly  near  one  another,  such  as  in  the  same   town or  county,   and   organizations,  such   as   government. The  influence   of  communities  is  suggested  in  the research  finding that  they differ in the  extent  to which their members practice certain health-related behaviors, such  as  smoking  cigarettes   or  consuming fatty  foods (Diehr et  al., 1993). There are  many  reasons for these differences.  For instance, a community’s  environmental characteristics seem to influence residents’  physical activity and diets  (Sallis et al., 2006; Story et al., 2008). Residents tend  to  be  more  physically active  and  have healthier diets in communities that have parks, are safe, and have stores  and restaurants with large selections of high-quality fruits, vegetables, and low-fat products.

The closest and  most continuous social relationships  for most people   occur within  the family, which can include nonrelatives who live together and share a strong emotional bond. As individuals grow and develop in childhood,  the family has an especially strong  influence. Children learn many health-related behaviors and  ideas from their parents, brothers, and sisters.  Parents can  set good  examples for healthful behavior  by using seat  belts,  serving and eating nutritious meals,  exercising,  not smoking,  and so on. Families can also encourage children to perform healthful behaviors  and praise them when they do. And as we have said,  an individual can influence the larger social unit. A family may stop eating  certain nutritious foods, such as broccoli or fish because one member has a tantrum when these foods are served.

The  role  of  biological,   psychological,   and  social factors in health  and illness  is not hard to see. What is more difficult to understand is how health  is affected by the interplay of these components, as the biopsychosocial model   proposes.

MBBS, MBA, MPH, & MD Phase B Resident, Department of Psychiatry, Bangabandhu Sheikh Mujib Medical University. Adjunct Faculty, Department of Public Health, ASA University, Bangladesh. Contact: arafatdmc62@gmail.com