Home       SAPA Project Test       Papers

Effects of Stress and Psychological Disorders on the Immune System

David B. Beaton
Rochester Institute of Technology

This is a review of the psychological field of psychoneuroimmunology (PNI) and how psychopathology has an impact on the immune system. Two areas of study of PNI are examined: first, how the psychosocial environment affects the health of an individual along with the impact stressors play on the immune system; second, the effects of psychopathology on the immune system and how perceived stresses are assessed. Coping strategies are also looked at where in some cases they have shown abilities in strengthening the immune system. The understanding of PNI is crucial in understanding the association between immunity, depression, stressors, and psychosocial aspects, along with their interactions with each other and their causal relations.

This is a review of a growing new field called psychoneuroimmunology (PNI), which incorporates facets of psychology, immunology, and neurosciences amongst many other fields. It attempts to understand the interactions between the nervous system, immune system and psyche. This is a rich area of research in which much work has done with many different theories. Specifically, one highly active area of research is where psychologists have been studying the effects that stress and psychopathology have on the immune system. This research has found correlations between stress, depression and the immune system.

The Immune System

The immune system is basically an interaction between cells and cellular products. The white blood cells (leukocytes), which are the main fighter cells of the immune system are made up of three classes; lymphocytes, monocytes, and granulocytes. Each type of cell has its own functions. Lymphocytes for instance, are subdivided into B cells, T-helper cells, T-suppressor cells, and natural killer cells. B cells are generally responsible for the production and secretion of antibodies. T-cells are responsible for making close and direct contact with the antigen. The other T cells are responsible for regulating the immune system; T-helper cells enhance whereas T-suppressor cells decrease the response.

In measuring the immune response, there are two basic ways; quantitatively measuring levels of cells, or second by using a functional measurement. In quantitative measurements, they are either a measure of the number of cells in a given volume of blood, or a percentage of each type of cell. In a functional measurement, lymphocytes, for example, are exposed to a non-specific antigen (mitogen) and the results of the exposure are then observed (O'Leary, 1990).

The psychosocial state of a person can have direct impacts on the immune system. For instance, stress has many different effects on the endocrine systems, including the well known fight or flight activation which is activations of the sympathetic adrenal-medullary (SAM) system, the hypothalamic-pituitary-adrenocortical (HPAC) system, and other endocrine systems.

Effects of Stress on the Immune System

Internal factors such as stress have been implicated in causing a deficient immune system because of the nature of the body's response in dealing with this problem. The capabilities of the immune system are diminished after frequent activation of the autonomic nervous system in the case of chronic stresses. The immune system is downgraded to be able to continuously functioning.

In a large study involving parents of both children with cancer and parents with children who were relatively healthy, the results showed that chronic psychological stress might reduce the immune system's reactions to hormonal secretions that were normally used to fight the inflammatory response (Miller, Cohen, & Ritchey, 2002).

Perceived mood also seems to play a role in immune system effectiveness. Having a positive attitude seems to correlate with an increased ability of the immune system in fighting diseases. In cases where patients have exhibited fear before a surgery, they have had a longer healing time afterwards. Correlations were observed in the number of lymphocyte cells and the person's level of optimism.

Cardiovascular diseases are another area where stress could have a negative effect. The natural response of the fight or flight activation mechanism could have a decidedly negative impact on the cardiovascular system. Since the activation of the fight or flight system involves an increase in the heart rate, a frequent activation could increase the possibility of a heart attack or other negative aspect of the disease. Specifically, a study was done in an industrial work environment in which a much higher frequency of cardiovascular mortality was found to correlate with an environment in which there was very little reward incentive (Kivimaki et al., 2002).

Even in relatively less dangerous health problems, mood can have an effect. A study with the common cold and emotions showed that participants with happy emotions exhibited a greater ability to fight off the cold when given a squirt of the rhinovirus (Jones, 2003).

A study done on students in an academic environment during exam time produced some convincing results. In the study, the level of T-cells and responses to mitogens was lower. Secondly, there was a higher self-reported occurrence of health problems, such as, upper respiratory-tract infections (O'Leary, 1994).

In the case of external factors, the social environment could play a huge role in immune functioning. If a person has an effective social support web, it has been shown to effectively increase the immune's systems abilities. The cardiovascular system could also have a positive response to this type of social support. Having positive social support could aid in blood pressure regulation, thus reducing the probability of a heart or related disease.

Coping Strategies

The definition of stress can be confusing. It can be a stimulus or demand, a response, or it may involve a process that involves both. Seyle is the champion of the commonly believed process of the physiological response; the alarm stage, resistance stage, and the exhaustion stage or also known as the general adaptation strategy. Lazarus promoted an alternative to this theory that also involves the emotional or psychological based response of the individual when faced with a stress. In his model, cognitive factors come into play like the cultural background of the individual or past experiences. First an individual determines the degree of threat that is perceived by the stress. Next coping strategies are assessed by the individual to effectively deal with the confronted situation.

Cox determined that both physiological and psychological components were equally important. He also recognized that each individual incorporated their own coping strategies.

The strategy an individual uses to cope with stress has in some studies shown a strong relationship with the ability of the immunes system. In the case of cognitive-behavioral stress management therapies, there has been shown effective means at reducing stress. The ability to proactively handle how one deals with their stress in everyday life could alleviate the constant activation of the endocrine system, which in turn increases the effectiveness of the immune system (Jones, 2003).

Inhibition of emotions could be another stress factor negatively affecting health. Bottling up negative emotions seems to tie up resources of the immune system. Individuals who disclosed a tragic event seemed to have an elevated immune response and generally were healthier than those who inhibited expression of these emotions. There is considerable evidence that talking about problems and using mental health services, decreases the number of sick days, and lowers health costs for these individuals (O'Leary, 1990).

Using a coping strategy which involves a denial or assessing that a particular illness or stress is beyond the control of the individual can prove to be an ineffective strategy. The person tries to escape reality, and refuses to use their social network to help deal with their problem. They believe that work requirements are more important than seeking therapy or treatments. This strategy can have a tragic result on an individual (Jones, 2003).

A large study of individuals with Aids was conducted in which participants of the study group were given advice on health, stress management techniques, psychological support, and problem solving skills regarding diagnosis. Initially after the 6-week study, there wasn't a noticeable result, but a follow up 6 months later showed profound decreases in psychological distress and higher levels of immune functioning (Glaser & Glaser, 1992).

Behavior Change

The field of PNI is not without controversy. One of the debatable topics is the causal relationship between stress, depression and immune response. Depression has been implicated in causing behavioral changes in people with major depressive disorder. Some of these lifestyle changes can be profound, such as, not eating, drug abuse, or disturbed sleep patterns. Some argue that it really is these "lifestyles" which is the culprit in reduced immune functioning. Having bad nutritional habits could starve the body of necessary nutrients to maintain high levels of white blood cells. As a result, the immune system downgrades its functioning and the person becomes more prone to diseases or inflammatory.

In a study done with depressed women and physical activity, 42 to 63 percent of the differences in immune functioning were observed to be related to physical activity. The study observed 32 depressed women and 32 non-depressed women. The production of lymphocytes was measured to determine the immune system's functioning (Hendersen, 1999).

Patients with cancer can have significant lifestyle changes as a result of their condition. They will have poor eating habits because of nauseating feelings which were not directly related to their treatments or conditions. They have disturbed sleep patterns, such as insomnia or waking up early. They also frequently develop drug problems. All of these factors seem to add additional stresses which impact the physiological effects. Targeting these stresses has had positive results on the health of individuals. Again, a study done with physical activity not only helped eliminate the bad physical habits, but it also decreased the depression and gave the clients a positive outlook (Anderson, Glaser, & Kiecolt-Glaser, 1994).

On top of lifestyle changes, a person's response to a known acquired disease, or even having symptoms of a disease could be another factor. A person under heavy stress or extreme depression may forgo seeking treatments for physical illness, thus increasing the likelihood of an escalation in the physical problem.

Effects of Psychological Disorders on the Immune System

Depression and Stress

The issue of whether stress causes depression or vice versa is another area of concern for PNI. Some wonder if depression is caused by stress or if depression itself is a form of a stressor. Pinpointing which is the primary cause of reduced immune response in PNI can be difficult.

Because both can be products of each other, it can be almost impossible to determine which has a more important role in effecting an individual's health. Stress can come in many forms. Anxiety causes stress, depression causes stress, and life events can also cause stress. On the other hand, stress can also trigger a major depressive disorder.

One theory of how stress can cause depression has its roots in the brain's mood and pleasure pathways. The stress exposure can cause the glucocorticoid hormone to be overly active which causes a depletion of norephinehprine levels in locus coeruleus neurons. This has an effect of slowing the attentiveness within the individual. They become emotionless and inactive (Salzano, 2003).

Perceived stress is quite possibly a cause in and of itself as well. One person may see a stressor as a far greater problem than another individual who may not feel the same degree of "stress" from the stressor. If an individual experiences great anxiety because of constant thought about a stressor, their fight or flight mechanism could be in perpetual heightened response. Just thinking about the stressor could set off the elevated response. These stresses amount to a constant initiating of the response multiple times a day if the thoughts preoccupy the individual.

Schizophrenia and the Immune System

There is a considerable amount of evidence that schizophrenic patients have longer healing times after major surgeries. A study investigated the levels of plasma interleukin in the blood of twenty-five control and schizophrenics during all stages of the surgery process of hemicolectomy and sigmoidectomy. Plasma IL-8 levels were significantly lower in the schizophrenic patients after surgery. Plasma cortisol concentrations were significantly lower during surgery for the schizophrenic patients as well. The conclusion of the study was that schizophrenic patients had a reduced ability for cytokine to fight inflammations. The reason for the findings could be explained by a schizophrenic's hypothalamus-pituitary-adrenal dysfunction. The endocrine system has close interactions with the immune system (Kudoh, Sakai, Ishiria, & Matsuki, 2001).

Summary and Future Considerations

This paper has shown that the immune system is not an isolated entity from the psychosocial state of an individual. A person experiences many stressors throughout a day and lifetime. These stressors are affecting the ability of the immune system to function at the highest possible level. Many important studies have shown that there is a correlation between these stressors and a person's health.

A person's psychological state is also a prominent factor in health. Depression influences the health of a person either by having a direct relationship with the immune system, or by indirectly influencing how a person takes care of themselves.

It is difficult to doubt that immunity and a person' psyche are interrelated, but what is difficult to explain is the causal relationship. What is really causing what? Some argue that stress causes depression, which causes the immune system to function improperly because resources are tied up in activating the fight or flight mechanism. Others argue that depression causes stress, which then causes fight or flight. And yet another group argues that a person's psychological state causes the individual to indirectly affect their health by bad nutritional, physical and sleep patterns.

Future studies need to address these issues. First, long term studies on people who both exhibit and don't exhibit depression and their daily stresses need to be done. The stresses these individuals experience and their responses, whether they are physical or not, need to be catalogued. Is the person experiencing stress directly related to the depression, or is depression a non-factor in the stresses. The person's health throughout the time they are experiencing the problems must be measured in different degrees. The degree of health problems, and their associated stressors or depressive states needs to be compared to determine whether stress or depression is the prominent factor.

Lastly, and most important, a person's physical habits need to be monitored to determine if the immune response is solely, partly or not at all affected by the individual habits and not the stressors or depression.

The purpose of this review was to show that a person' psychosocial environment is a primary cause either directly or indirectly in how a person feels physically, or recovers from illness. This could have profound implications in future treatments administered to people with morbid diseases. Psychotherapy and behavioral therapy may prove to be an extremely useful tool in helping these individuals to recover or deal with their illness without inhibiting the natural abilities of the immune system. If we know the true cause effect relationship, we could develop these psychosocial treatments to specifically deal with not only the individual's health state, but also their depression or stressors, which in turn could improve the chances of physically recovering.

Peer Commentary

The Role of Stress in Physiological Disorders

Andrew P. Ochtinsky
Rochester Institute of Technology

The basic premise of this paper was that psychosocial environment and psychopathology have measurable effects on the immune system. The paper showed this to be true and suggested that coping techniques for stress can greatly improve a person's physical health.

Chronic psychological stress, such as dealing with a terminal illness in the self of or a loved ones, has been shown to reduce immune effectiveness. Positive attitude correlates strongly with increased ability of the immune system to fight pathogens. Performance stress, such as that of students during an examination period, seems to correlate with a decrease in disease-fighting cells and the response of the immune system to mitogens. Persons with an effective social support structure have been shown to have stronger immune abilities. Thus, other things being equal, psychosocial environment has a very powerful effect on the immune system.

Stress-coping mechanisms have an effect on the immune system. Those using cognitive-behavioral stress management therapies have been shown to have a more effective immune system. Relief of stress can assuage the immune-decreasing properties of strong negative emotions, which weaken immune response over time. Coping strategies that involve denial of loss of control over personal health correlate with decreased immune abilities. Even in individuals with acquired immune deficiency syndrome (AIDS), positive stress management techniques and psychological support were shown to have profound effects on psychological distress and immune functioning. These arguments are absolutely convincing regarding the effects of stress and stress management on the human immune system.

The paper showed that depression and anxiety have significant negative effects on the immune system. These disorders cause considerable stress, which, given what was already shown about the effects of stress, has a major effect on the immune system. It suggested that, because depression and anxiety can have this effect, it is important not only to treat the disorders but also to teach methods of coping with the associated stress to prevent immune problems.

Future studies could definitely address methods of coping with stress and psychological disorders to increase the effectiveness of the immune system. This paper might have suggested the efficacy of certain types of therapy in positively affecting the immune system by way of reducing and managing stress, thus providing direction for future studies. It is also important to suggest that all individuals, not just those with psychological disorders, can benefit greatly from stress management techniques, given that there is no upper limit on immune performance.

Overall, the paper illustrated its points very nicely and with few flaws. It was effective in convincing me of the role of stress in physiological health.

Peer Commentary

The Role of Prior Protective Factors

Kathryn O. Tacy
Rochester Institute of Technology

This paper gave an overview of psychosocial and psychological implications in states of heightened stress. The causal factor was a main focus of attention and inquiry, as well as the effects of stress on the physical and psychological self.

Attitude, social networks, and a healthy diet are woven together in their importance for physical and mental health. Attitude is one thing humans have great control over, but for the most part people choose to let their attitude run them, or they think their situation has to change before their attitude can change, which is usually not the case. When faced with a challenge of any sort, people make a decision how it is going to affect them. The outcome of that decision is a big indicator of the events to follow. People can choose to take a positive attitude, which could lead to better judgment-making and a quicker recovery from the situation. People can also choose to see only negative aspects, which often clouds other avenues or opportunities. These choices are not so cut and dry, however, and can sometimes be realized a short time after the fact. This is a point where perhaps one is capable of making a stronger decision having gone through some of it already. Having a good social network of family and friends is a great stress reducer if used properly. Being able to trust those people with your vulnerability can be hard to do but does not have to be. People must remember that reciprocity is important for a good "shoulder to lean on" relationship. Diet is another big factor in overcoming physical or mental illness. Even though depression and stress can cause poor eating habits, a good diet to start with will help keep one better prepared in any event.

Another serious aspect of wellbeing is fear. By fear I mean the lack of a willingness to get medical and psychological treatment due to the fear of discovering a real problem. The irony of this situation is that, by a lack of "check-ups," a person runs an even greater risk of not getting treatment or getting treatment that may be too late to have a profound effect. Another serious aspect of wellbeing is habit. If a person succumbs to a depressive state, then unhealthy eating habits and states of mind can become routine. After a person overcomes depression, these problems may be overlooked and become future coping mechanisms, which can lead to long-term dysfunction that may repeat the cycle that was first to be overcome!

This paper gave good arguments for both sides of the causal conflict and had good emphasis on coping and pharmaceutical therapy and its dual importance in recovery. I would, however, be interested in an elaboration on a few points. The percentage range of 42-63% for immune efficacy in physically active women seemed a bit vague to me. Was it 63% or was it 42%? There seemed to be a lot of room for causal interpretation here. Lastly, there was a report of nausea in cancer victims that was said not to be due to current conditions or therapy and that caused an increase in good eating habits. It was previously stated, however, that these lifestyle changes were a result of their current conditions. If the nausea was not due to any of the above mentioned circumstances, then what was its cause? Was there some outlier at work here? Overall this paper was effective in getting across the seriousness of stress and its potential implications for the immune system, as well as stating the importance of prior well being.

Peer Commentary

The Immune System: Quite a Mouthful

Jason J. Zodda
Rochester Institute of Technology

Think about your last bad day. How did you feel? Were you a little more tired then usual? Did you feel unusually fatigued? The chances are you probably did. Why does this happen?

No one really knows for sure why the immune system acts weak when one thinks it should function strongly. The evolutionary perspective is the strongest view on the market. It claims that the immune system is suppressed during periods of stress to serve as a protective function in the evolution of our species. The belief is that it helps prevent people from developing autoimmune diseases (Carson, Butcher, & Mineka, 2002).

In David B. Beaton's "Effects of Stress and Psychological Disorders on the Immune System," he mentioned a few reasons why the immune system is suppressed, but in sum, this was what the paper lacked most. The author briefly mentioned a correlation between lymphocyte cells and the amount of healing time after surgery, but he did not describe it any further.

Beaton mentioned an interesting connection between the body's "fight or flight" response and the cardiovascular system. He made a strong point on how the increase in heart rate during the bodily response can possibly lead to a heart attack or some other negative affect on the cardiovascular system.

Finally, Beaton described the relation between schizophrenia and the immune system. Schizophrenic persons have a longer rehabilitation time after surgery. The conclusion was that schizophrenic persons' hypothalamus-pituitary-adrenal dysfunction, which worked along with the immune system, was at fault. Another important finding was that schizophrenic persons have a lower ability for cytokine (a protein) to fight inflammations.

Beaton should elaborate more on why the immune system fails when under stress. The points that Beaton made on the "flight or fight" response and the schizophrenic relation were very compelling, and I hope to see more information about these topics in his author response. This paper was clear and attention-grabbing. I hope it will lead to more investigation on this important topic.

Author Response

Just Scratching the Surface of Psychoneuroendocrinology

David B. Beaton
Rochester Institute of Technology

I really appreciated the commentaries on my paper--they were well thought-out and had great points. One point seemed to be a consensus among the peer commentators--that I could have elaborated more on some of the studies and ideas presented. I wish I could have. This area of research has ocean depths of research and ideas, and it has not even began to touch on the potential knowledge that can and will be gained in the future. I could have gone on for pages, but unfortunately I needed to compress the paper into a format that readers would enjoy without becoming entrenched too deeply in details.

Otchinsky suggested that I elaborate on the efficacy of different coping techniques. In reply, it seems that behavior therapies have been the most successful. Specifically, using exercise as a treatment appears to have a universal benefit for almost all types of stress and greatly helped persons with diseases. This makes sense, considering that personal health decisions play a prominent role in immune functioning. It would also make sense that this relieving of "caged in" tension by venting through exercise would have great benefits on the psychological state of an individual.

Tacy first questioned the nausea that cancer patients felt that were not related to their treatments and what they meant for physical habits. The nausea I was referring to was the sick-to-the-stomach feelings that people get when they are under great stress. We have all felt sick just by thinking of something stressful, and as a result we lose our appetite. So in this case the thoughts about cancer bring about stress and poor eating habits. Targeting this stress through behavior therapy allowed cancer patients to decrease stress and increase positive emotions.

Tacy also questioned the statement that 42 to 63 percent of differences in immune functioning were related to exercise. Not every woman had the same results from exercise; some had only 43 percent improvement, whereas others had 63 percent improvement. This finding corroborates the understanding that even in a worst-case scenario there are dramatic results from using exercise in a stress-reducing regime.

Zodda suggested that I elaborate on how the immune system is actually affected. When I began the paper, I originally wanted to go in depth in this area, but I soon realized that I would need more than just one paper to fairly address the immune system. I decided purposefully to shy away from most of the extremely technical details so as not to bore readers. But to put the findings in a nutshell, the immune system is a perfectly balanced system of cells that do their jobs and then quit using resources when their jobs are complete. Persons under stress throw off the balance of their immune system. As a result, certain immune cells become overactive and thus prevent other ones from functioning as they should. The communication among cells is broken down, and the entire immune system becomes unstable and ineffective.

I hope this response addresses some of the questions brought up by the peer commentators. Admittedly, there are still weaknesses in the paper, but overall I hope that the paper allows readers to enjoy a high level understanding of psychoneuroendocrinology. I know that for myself, studying these topics has allowed me to take a second look at how I deal with everyday stressors.


Konsman, P. J., Luheshi, G. N., Bluthe, R., & Dantzer, R. (2000). The vagus nerve mediates behavioural depression, but not fever, in response to peripheral immune signals: A functional anatomical analysis. European Journal of Neuroscience, 12, 4434-4446.

Snyder, R. (2000). Overview of the toxicology of benzene. Psychological Review, 105, 83-107.

Maier, S. F., & Watkins, L. R. (1998). Cytokines for psychologists: Implications of bidirectional immune-to-brain communication for understanding behavior, mood, and cognition. Psychological Review, 105, 83-107.

Bower, B., (1985). Severe depression depresses immunity. Science News, 127, 100.

Bower, B. (1991). Questions of mind over immunity. Science News, 139, 216-218.

Carson, R. C., Butcher, J. N., & Mineka, S. (2002). Fundamentals of abnormal psychology and modern life. Boston: Allyn and Bacon.

Davis, P. A., Corless, D. J., & Aspinall, W. C. (2001). Effect of CD4[supp +] and CD8[Sup +] cell depletion on wound healing. British Journal of Psychology, 88, 298-305.

Denman, A. M. (1986). Immunity and depression. Science News, 293, 464.

Glaser, R., Kiecolt-Glaser, J. K., & Andersen, B. L. (1994). A biobehavioral model of cancer, stress, and disease course. American Psychologist, 49, 389-404.

Jones, J. (2003). Stress responses, pressure ulcer development and adaptation. British Journal of Nursing, 12, 17-23.

Kivimaki, M., Leino-Arjas, P., Luukkonen, R., Riihimaki, H., Vahtera, J., & Kirjonen, J. (2002). Work stress and risk of cardiovascular mortality: Prospective cohort study of industrial employees. British Medical Journal, 325, 857-861.

Maes, M., Bosmans, E., Meltzer, H. Y., Scharpe, S., & Suy, E., (1993). Psychiatric disorders and immune activity. Advances: The Journal of Mind-Body Health, 10, 49-52.

O'Leary, A. (1990). Stress, emotion, and human immune function. Psychological Bulletin, 108, 363-382.

Salzano, R. (2003), Taming stress. Scientific American, 289, 88-98.

Weisse, C. S. (1992). Depression and immunocompetence: A review of the literature. Psychological Bulletin, 111, 475-489.

Last modified November 2003
Visited times since November 2003

Home to Personality Papers

Home to Great Ideas in Personality