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Psychosocial stress and its relationship to illness behavior and illnesses encountered commonly by family practitioners
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0271-5384.81.030155-0550200~0 0 1981 Pergamon Press Ltd
PSYCHOSOCIAL STRESS AND ITS RELATIONSHIP TO ILLNESS BEHAVIOR AND ILLNESSES ENCOUNTERED COMMONLY BY FAMILY PRACTITIONERS MICHAEL Department
of Family
A.
GODKIN
and CINDY A.
RICE
and Community Medicine, University of Massachusetts 55 Lake Avenue North, Worcester, MA, U.S.A.
Medical
Center,
Abstract-&Computerized, clinical data, pertaining to 21.000 patients at 4 family health centers, were used to examine possible relationships between psychosocial stress and physically manifested illnesses. Statistical tests revealed a significantly higher age-sex standardized prevalence rate of somatic complaints (e.g. arrythmia, chest pain. cystitis, cellulitis, obesity. abdominal pain, lower back pain, hypertension, headaches. dizziness. malaise, acute bronchitis, osteoarthritis, acute upper respiratory tract infections) in patients diagnosed with 1 of 4 selected indicators of psychosocial stress (i.e. anxiety, depression couple conflict. child abuse.neglect) compared with the patient population which was not diagnosed as stressed. The findings are discussed in the context of the case-control research design used in the study. Although causal relationships cannot be established as a definitive outcome of the study. the findings lend further support to the mounting evidence that psychosocial stress is a contributing factor in a wide variety of physical complaints encountered by Primary Care physicians.
have complicated the determination of relationships between psychosocial stress and illness will be highlighted. In particular, the concept of psychosocial stress will be elaborated upon and difficulties determining causal relationships between psychosocial stress and illnesses will be outlined.
INTRODUCTION
The focus of much of the literature on what has been called, somewhat loosely, ‘stress* and illness’ is on the contribution of stressful life events to the onset of catastrophic illnesses, particularly coronary conditions, Considerably less research exists on possible relationships between the psychosocial stresses, or what Kanner er a/. [l] termed the ‘hassles’, of daily living and common, less threatening illnesses,+ encountered frequently by Primary Care physicians. An increased understanding of the role of such psychosocial stresses in triggering or causing common somatic problems has potential ramification for more effective management of these medical problems which underlie the vast majority of visits for health care in the United States. It seems reasonable to suggest, in fact, that the early recognition and effective management of psychosocial stress associated with common physical complaints constitutes the sound practice of what is commonly called preventive medicine. Early intervention in the stress-illness cycle could reduce the incidence of more catastrophic illnesses associated with accumulated life stresses. This paper, then, has as its focus an examination of possible links between psychosocial stress and common somatic problems encountered by physicians at 4 family health centers. As background to the study, some conceptual and methodological issues which
CONCEPTUAL
ISSUES IN PSYCHOSOCIAL
STRESS RESEARCH
A review of the more recent literature indicates that considerable agreement exists concerning the conception of psychosocial stress as a transactional phenomenon, involving a dynamic and interdependent relationship between the psychosocial functioning of an organism and the social environment in which it exists. Within this broad framework, however, different components of the psychosocial stress concept have been emphasized. Some have viewed psychosocial stress as primarily a stimulus, or encironmental stressor. This view of psychosocial stress as an objective phenomenon (i.e. objective stress) is characteristic of life events research, in which certain life events (e.g. death of loved one, divorce, job changes, etc.) are assigned weights, with respect to their degree of associated stress, and an illness susceptibility index determined for an individual, dependent upon the number of life changes he/she has experienced [2]. Others have focused on the subjective nature of psychosocial stress (i.e. subjective stress). Lazarus [3] for example, has argued that individuals’ coping abilities are much more important than the nature of objective stressors in determining the level of stress that an individual experiences. The coynitioe mediation of an environmental stressor, and the way it is perceived subsequently, with respect to its degree of threat, is seen as the essential determination of the degree of stress. Others have focused their attention on psychosocial stress viewed as an emotional response (i.e. the organic and psychological response of an individual to some environmental stimulus) [4].
*The term ‘stress’ in its original use by Hans Selye referred to physiological imbalances induced by physical trauma. More recently the use of the term has been extended to refer, also, to situational, psychological, and emotional states of disequilibrium. It is this latter perspective which is elaborated upon in this paper, and the term psychosocial stress is used to differentiate a more psychosocral interpretation of stress from its original definition. t The term ‘illness’ is used in this paper to describe physically manifested. or somatic, medical problems, including symptoms and diagnoses. 155
The perspective of this paper is one that had been detailed elsewhere, in which psychosocial stress is viewed as a dynamic phenomenon involving a series of stages [5]. These ‘stress stages’ involve an environmental stimulus (i.e. objective stress) which is perceived by an individual as threatening to self identity (i.e. subjective stress). In response to such a threat an individual undergoes certain organic and psychological changes (i.e. stress response or strain). Dependent on the individual’s ability to cope with the particular threat, certain consequences are possible with respect to psychological and physical health. METHODOLOGICAL
ISSUES IN STRESS
RESEARCH
Methodological problems in stress research have hindered a determination of the nature of causal re~ationships between psychosocial stress, illness, and illness behavior (i.e. behavioral responses to symptoms with respect to seeking medical care). At least 5 possible relationships can be considered: (a) psychosocial stress causes illness: (b) illness causes psychosocial stress: (c) psychosocial stress and illness are interdependent such that either one can cause and reinforce the other; (d) psychosocial stress causes certain illness behaviors and not illness (e.g. greater awareness of symptoms and likelihood of consultation with a physician); (e) psychosocial stress causes certain illness behaviors (e.g. psychosocial stress results in delayed seeking of medical care for minor symptoms) which in turn causes more serious iilnesses. The difficulty of untangling the web of causality has its roots in the implementation of certain research designs. The majority of stress studies. for both ethical and practical reasons, employ retrospective or casecontrol designs in which the subjects of the research have a particular illness or illnesses and an attempt is made to measure prior psychosocial stresses. Such designs, based on recall, have the difficulty of proving. conclusively, that psychosocial stress predates onset of the symptoms of the illness. Also, many studies, for practicaf purposes, focus on clinical populations which have seiected themselves from a ~pulation at risk. not only on the basis of illness. but also a variety of psychosocial considerations. Consequently. diagnostic information from the medical record may reflect simply behavioral patterns rather than patterns of morbidity. Moreover, many of these studies focus on the population of a particular clinic, and, as such, may give a highly distorted view of even the character of all those who seek help. To determine findings which are generalizeable, studies “require reliable and valid measurement of the dependent variable. a sizeable representative sample of persons suffering from the condition under the study, and a revelant comparison group” [6].
* The use of diagnostic checklists. and the definition of these diagnoses according to ICHPPC. provide an objective framework for the recording of data by different providers. although. ultimately, the subjective nature of the diagnostic p:actice of physicians must be acknowledged.
In examining the association between psychosocial stress and illness, the authors have attempted to satisfy the above criteria as much as possible. MATERIAL
AND METHODS
Data for the study are drawn from 1 year’s (July 197%June 1979) clinical data at 4 family health centers affiliated with the Family Practice Residency of Massachusetts Medical Program, University Center. Worcester. Two of these centers are located in the city of Worcester (population approximately 175.000) and are within 5 miles of the Medical Center. The third facility is situated in a rural town (population approximately 3ooO). some 25 miles from Worcester. Each of these 3 health centers is involved in training Family Practice residents. The fourth center. which did not train residents during the study year, is located in a city of approximately 80,000 people. 30 miles north of Worcester. Throughout the study period, there were 13 staff physicians and 3 1 Family Practice residents providing care at these 4 centers. Data for each of their encounters during the study year were entered into a computer housed within the Medical School. An audit of billing records at each health center indicated that 98”,, of all patient visits to the health center had encounter forms completed appropriately and entered into the computer. The number of encounters computerized during this period was 58,862 at all 4 health centers, for over 21.000 patients. The majority of patients visiting were female (571,,), and the largest proportion of patients were concentrated in the younger age groups (28”. under I5 years. 24”,, between 15 and 24 years, 17”,, between 35 and 34 years, and less than 8”,, over age 65). Data recording is facilitated by the use of check-list encounter forms which are precoded. using the International Classification of Health Problems in Primary Care (ICHPPC), [7]* and filled out by health center providers. The psychosocial and stress-related problems to be used as indicators of psychosocial stress in this study are classified as ‘Mental Disorders’ and ‘Social. Marital, Family Problems and Maladjustment’ in ICHPPC. The computerized encounter form data pertaining to the above diagnoses were found to have the same degree of reliability as the medical chart, the tr~~ditionally accepted source of much clinical research. In a I”,,, random sample of all patient encounters in the study period, the proportion of all psychosocial problems, omitted from the computer but present in the medical chart. was found to be equal to the proportion of all such diagnoses omitted from the medical chart but recorded on the computer (i.e. 17”,,). [S]. For the purposes of this paper 4 specific diagnoses were selected from the psychosocial category in ICHPPC. as indicators of psychosocial stress. The choice of the diagnoses was based on a desire to be consistent with a concept of stress which is multidimensional. involving both env~ronmen~~i stressors and emotional stress responses. The preceded diagnoses of anxiety and depression (ICHPPC codes 3000, 3004) were used as indicators of emotional stress, and couple conRict and child abuse and neglect (ICHPPC codes 1084, 1085) were used as indicators of environmental stressors. Child abuse and couple conflict
Psychosocial
stress and illness
conceivably, be considered as indicators or symptoms of psychosocial stress. Their inclusion as environmental stressors is based on the fact that they define pathological family situations or envjronments and the likelihood that both problems will cause or exacerbate emotional stress in family members. A ‘case-control’ research design was adopted for the study. Morbidity profiles were compared for stressed patients (‘cases’) and nonstressed patients (‘controls’) within the study population. Subjects were selected from a clinical population and, as such. are a selfselected group which might not represent the general population. The inclusion in the study, however, of 4 clinical sites, variously located with diverse patient characteristics (e.g. rural versus urban, small town versus large town, primarily Medicaid at one site and primarily Blue Cross at another site) suggest that reported findings are widely generalizeable. could,
R~seurch yuestiom Specifically, the research is designed to: (1) investigate the relationship of psychosocial stress (considered as both an environmental stressor and emotional stress) to somatic health problems (i.e. illness); (b) examine the relationship of psychosocial stress to illness behavior; (c) consider the role of stress on the general or specific nature of illness susceptibility. Again, the emphasis of this report is not on catastrophic illness, as is generally considered in the literature, but physically manifested illnesses encountered commonly by Primary Care physicians.
In the first phase of the study, psychosocial stress was defined as an emotional stress. The prevalence of the ‘most common’ somatic symptoms and diagnoses was determined for the two groups of ‘cases’, i.e. separately, for patients who were diagnosed with anxiety or depression (the 2 chosen indicators of emotional stress). Any somatic problem which occurred in at least 5”;, of the cases was included in the analyses. Comparisons were made with the prevalence of the same somatic conditions in the rest of the patient population (‘controls’) by calculating a standardized morbidity ratio (SMR)* for each associated health problem among anxiety patients (N = 191) and among depression patients (N = 356). In the second phase of the study. psychosocial stress was defined as an environmental stressor, and the prevalence of the most common somatic conditions was determined for the two groups of ‘cases’: i.e. separately, for patients with each of 2 famiiy problems, couple conflict (N = 238) and child abuse/neglect (N = 194) the chosen indicators of environmentai stressors. Any somatic problem which occurred in at least 551;,of the cases was included in the analyses. Comparisons were then made with the prevalence of * Using all health center patients as the standard population and the indirect method of adjustment. the age-sex specific prevalence rates of a given somatic problem were applied. separately, to the age-sex distribution of anxious and depressed patients, to obtain an expected prevalence rate for both groups. A standardized morbidity ratio was then calculated for each group of anxiety and depression patients, i.e. the observed prevalence divided by the expected prevalence during the study year.
157
the same health problems in the rest of the patient population (‘controls’) using the above method of age-sex standardization. For each of the 4 case groups and their respective controls, either the normal or Poisson distribution was applied to the illness occurrence data (depending on the magnitude of the expected frequency of illness) to test for significant differences in illness occurrence between the stressed and nonstressed groups. RESULTS
As Table 1 indicates, after adjusting for sex-age differences between anxiety patients and the total patient population, and based on the normal or Poisson distribution, the observed prevalence rates of some of the physical problems associated with anxiety patients were significantly higher than the expected (i.e. cystitis. arrythmias, chest pain. abdominal pain, hypertension, headaches, acute bronchitis, dizziness, weight loss, and warts.) Table 2 demonstrates higher than expected prevalence rates of certain somatic complaints associated with depression patients (i.e. chest pain, boil/cellulitis. abdominal pain, low back pain, headache, vaginitis. obesity, hypertension. dizziness. osteoarthritis and malaise/fatigue). One could argue that the higher than expected prevalence rates of the above somatic problems in patients who are anxious or depressed is attributable to an increased tendency to make more visits for health care. since the probability that a patient will be diagnosed with any of the illnesses in Tables 1 or 2 is. among other factors. related to the number of visits made for health care (i.e. illness behavior). Depressed and anxious patients did make significantly higher (P < 0.001) Table
numbers
of visits,
1. Reiatjonship
on average,
between
anxiety
(5.5 and
5.4
and illness Standardized Morbidity Ratio?
Acute upper respiratory infection Hypertension Abdominal Pain Vaginitis Acute Bronchitis Obesity Cystitis. urinary infections Diabetes mellitus Arrythmia Dizziness, giddiness Chest pain Wetght Ioss Osteoarthritis Low back pain Headache Warts
1.39 1.96*** 2.41***
1.25 1.75** 1.10 3.58*** 0.79 4.!%*** 3.54*** (X19***
11.Yi*** 1.11 1.20 1.93* 4.69***
*** P < 0.001. ** P < 0.01. * P < 0.05. t SMR = .stcdurdixd
nmhidity rutio of observed to expected prevalence of illness among anxiety patients during year. age-sex adjusted by indirect method. The SMR compares the illness prevalence between anxiety patients and all other patients.
158
MKXAEL A. GODKINand
respectively) than non-depressed and non-anxiety patients (2.6 in both cases). However, since comparisons of the prevalence of problems between stressed and nonstressed groups were based not on frequency data alone, but on standardized, expected frequencies using the illness prevalence rates of the patient population, this argument is not valid (the prevalence rate of a particular illness in this context indicates the percentage of the total number of illnesses that is constituted by that illness). It follows that the proportion of the total illnesses accounted for by a particular illness should be equal for both stressed and non-stressed groups if the 2 groups actually have the same morbidity profiles, regardless of their unequal visit rates. However, these data reveal that many rates of illnesses were significantly higher for the stressed group. These findings would suggest, then, that the differences in prevalence rates reported in Tables 1 and 2 are not dependent upon the number of visits made by anxious or depressed patients, It is interesting to note that many of the illnesses significantly associated with anxiety and depression are common to both (i.e. abdominal pain, chest pain, headache, hypertension and dizziness). It is also noteworthy that a number of illnesses are more characteristic of depression patients than anxiety patients (i.e., obesity, low back pain, osteoarthritis, and vaginitis) and of anxiety patients than depressed (bronchitis, arrythmias, weight loss, warts.) It appears, then, that anxiety and depression increase the general susceptibility to illness rather than being related to one particular illness. However, the data indicate that there may be some specificity with respect to the types of illnesses that are induced by different forms of emotional stress. Although many illnesses associated with anxiety or depression are common to both, certain illnesses are more specific to either anxiety or depression.
Table 2. Relationship
between
depression
and illness
Standardized Morbidity Ratio? Hypertension Obesity Osteoarthritis Low back pain Acute upper respiratory Abdominal pain Headache Chest pain Malaise, fatigue Acute bronchitis Diabetes mellitus Dizziness, giddiness Vaginitis Boil, cellufitis
infection
1.49** 1.96** 2.57*** 2.64*** 1.17 2.25*** 3.28*** 8.52”* 3.34*** 1.20 1.36 2.95*** 2.21*** 3.16***
*** P < 0.001. ** P i 0.01. t SMR = standardized morbidity rutio of observed to expected prevalence of illness among depression patients during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between depression patients and all other patients.
CINDY A. RICE
Table 3. Relationship
between
couple
conflict
and illness
Standardized Morbidity Ratio? Acute upper respiratory Obesity Abdominal pain Headache Acute bronchitis Hypertension
infection
1.10 2.19***
I x0*** 2.70*** 2.16*‘* 7.x2***
*** P < 0.001. t SMR = srandardized morbidit), rurio of observed to expected prevalence of illness among patients with couple conflict during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between ‘couple conflict’ patients and all other patients.
Psychosocial stress as e~~ir(~~rnel~t~l~ stressor From a perspective of stress as an environmental stressor, analyses using either the normal or Poisson distribution indicated a significantly higher prevalence of illnesses among patients with family problems, than would have been expected on the basis of the rates of the same diagnoses in the total patient population. The prevalence rates of headaches. abdominal pain, obesity, bronchitis and hypertension were significantly higher in patients with couple conflict recorded compared with the rest of the patient population (see Table 3). Patients with recorded abuse or neglect had significantly higher than expected rates of bronchitis. abdominal pain, acute URI, viral infections, and obesity compared with the rest of the patient population (Table 4). As argued earlier. the use of rates in the analyses means that these differences are not attributable to significant differences (P -C 0.001) in utilization rates between patients diagnosed with couple contfict (5.0 visits, on average) or child abuse (5.2 visits) and patients with neither couple conflict (2.6 visits) nor child abuse (2.6 visits) problems. Table 4. Relationship
between
abuse,‘neglect
and illness Standardized morbidity Ratio?
Viral infection Acute upper respiratory Acute bronchitis Abdominal pain Obesity Acute otitis media
infection
5.31*** 1.87* 2.07”s 1.7* I .46* I.05
*** P < 0.001. * P < 0.05. 7’ SMR = .standardi;ed morbidit~~ rutio of observed to expected prevalence of illness among patients with abuse,’ neglect during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between ‘abuse.: neglect’ patients and all other patients. CONCLUSION
The data presented in this study lend support to the existence of a relationship between psychosocial
Psychosocial
159
stress and illness
stress, viewed either as an environmental stressor or as an emotional stress, and illnesses encountered commonly by Primary Care physicians. The data do not the direction of causality establish, definitively, between psychosocial stress and illness: a more sophisticated and time-consuming prospective study involving survey techniques is necessary to establish the nature of causality. Strong evidence is provided, however, which supports a hypothesis that psychosocial stress leads to illness rather than vice-versa. The examination of the multi-dimensional nature of stress and, in particular. considering stress as a stimulus would appear to provide considerable support for such a hypothesis. It is highly unlikely that the physical problems associated with family problems are, in fact. the cause of such problems. It is much more likely that the familial problems. themselves. lead to the onset of illness and manifestation of physical symptoms. There are significant differences in the numbers of visits made by stressed and non-stressed patients but these differences do not account for the higher rates of illnesses in the stressed groups. Further studies, using different research methodologies, are needed, however, to determine whether the morbidity data presented in this paper reflect the existence of clinically verifiable somatic problems. It may be that the diagnosed somatic complaints represent, simply, patients’ experiences of physical discomfort because of heightened awareness of body functioning and lower pain thresholds in periods of stress, as in hypochondriacal behavior. Finally, the evidence in this paper
indicates that psychosocial stress increases an individual’s general susceptibility to illness, and that certain stressors and emotional stresses appear to be specific to certain diagnoses.
REFERENCES
1. Kanner A. D.. Coyne J. C., Shaefer C. and Lazarus R. S. Comparison of two modes of stress measurement:
2. 3.
4
5.
6 7.
8.
daily hassles and uplifts versus major life events. Forthcoming in J. Behac. M. Holmes T. H. and Rahe R. H. The social readjtistment rating scale. J. Psychosom. Rrs. 2, 213, 1967. Lazarus R. S. Cognitive and personality factors underlying threat and coping. In Psychological Stre.s.s (Edited by Appley M. H. and Trumbull R.), pp. 151-157. Wiley, New York, 1974. Arnold M. B. Stress and Emotion. In P.s~~cho/oyicul Srre.ss (Edited by Appley M. H. and Trumbull R.), pp. 123-140. Appleton-Century-Crofts, New York. 1967. Cobb S. A model for life events and therr consequences. In Strvssfil Lifr Ecents (Edited by Dohrenwend B. S. and Dohrenwend P. B.). pp. 15 1-I 57. Wiley, New York, 1974. Mechanic D. Stress. illness and illness behavior. J. hum. Stre.ss 2, 5. 1976. World Organization of National Colleges, Academies. and Academic Associations of General Practitioners.: Family Physicians. Intrrnationul Classificurion ctf Hrulfh Problems in Primur~~ Cure. American Hospital Association, Chicago, 1975. Rice C., Godkin M. and Catlin R. J. 0. Methodological. technical and ethical issues of a computerized data system. J. Fam. Prucf. 10, 665, 1980.
0271-5384.81.030155-0550200~0 0 1981 Pergamon Press Ltd
PSYCHOSOCIAL STRESS AND ITS RELATIONSHIP TO ILLNESS BEHAVIOR AND ILLNESSES ENCOUNTERED COMMONLY BY FAMILY PRACTITIONERS MICHAEL Department
of Family
A.
GODKIN
and CINDY A.
RICE
and Community Medicine, University of Massachusetts 55 Lake Avenue North, Worcester, MA, U.S.A.
Medical
Center,
Abstract-&Computerized, clinical data, pertaining to 21.000 patients at 4 family health centers, were used to examine possible relationships between psychosocial stress and physically manifested illnesses. Statistical tests revealed a significantly higher age-sex standardized prevalence rate of somatic complaints (e.g. arrythmia, chest pain. cystitis, cellulitis, obesity. abdominal pain, lower back pain, hypertension, headaches. dizziness. malaise, acute bronchitis, osteoarthritis, acute upper respiratory tract infections) in patients diagnosed with 1 of 4 selected indicators of psychosocial stress (i.e. anxiety, depression couple conflict. child abuse.neglect) compared with the patient population which was not diagnosed as stressed. The findings are discussed in the context of the case-control research design used in the study. Although causal relationships cannot be established as a definitive outcome of the study. the findings lend further support to the mounting evidence that psychosocial stress is a contributing factor in a wide variety of physical complaints encountered by Primary Care physicians.
have complicated the determination of relationships between psychosocial stress and illness will be highlighted. In particular, the concept of psychosocial stress will be elaborated upon and difficulties determining causal relationships between psychosocial stress and illnesses will be outlined.
INTRODUCTION
The focus of much of the literature on what has been called, somewhat loosely, ‘stress* and illness’ is on the contribution of stressful life events to the onset of catastrophic illnesses, particularly coronary conditions, Considerably less research exists on possible relationships between the psychosocial stresses, or what Kanner er a/. [l] termed the ‘hassles’, of daily living and common, less threatening illnesses,+ encountered frequently by Primary Care physicians. An increased understanding of the role of such psychosocial stresses in triggering or causing common somatic problems has potential ramification for more effective management of these medical problems which underlie the vast majority of visits for health care in the United States. It seems reasonable to suggest, in fact, that the early recognition and effective management of psychosocial stress associated with common physical complaints constitutes the sound practice of what is commonly called preventive medicine. Early intervention in the stress-illness cycle could reduce the incidence of more catastrophic illnesses associated with accumulated life stresses. This paper, then, has as its focus an examination of possible links between psychosocial stress and common somatic problems encountered by physicians at 4 family health centers. As background to the study, some conceptual and methodological issues which
CONCEPTUAL
ISSUES IN PSYCHOSOCIAL
STRESS RESEARCH
A review of the more recent literature indicates that considerable agreement exists concerning the conception of psychosocial stress as a transactional phenomenon, involving a dynamic and interdependent relationship between the psychosocial functioning of an organism and the social environment in which it exists. Within this broad framework, however, different components of the psychosocial stress concept have been emphasized. Some have viewed psychosocial stress as primarily a stimulus, or encironmental stressor. This view of psychosocial stress as an objective phenomenon (i.e. objective stress) is characteristic of life events research, in which certain life events (e.g. death of loved one, divorce, job changes, etc.) are assigned weights, with respect to their degree of associated stress, and an illness susceptibility index determined for an individual, dependent upon the number of life changes he/she has experienced [2]. Others have focused on the subjective nature of psychosocial stress (i.e. subjective stress). Lazarus [3] for example, has argued that individuals’ coping abilities are much more important than the nature of objective stressors in determining the level of stress that an individual experiences. The coynitioe mediation of an environmental stressor, and the way it is perceived subsequently, with respect to its degree of threat, is seen as the essential determination of the degree of stress. Others have focused their attention on psychosocial stress viewed as an emotional response (i.e. the organic and psychological response of an individual to some environmental stimulus) [4].
*The term ‘stress’ in its original use by Hans Selye referred to physiological imbalances induced by physical trauma. More recently the use of the term has been extended to refer, also, to situational, psychological, and emotional states of disequilibrium. It is this latter perspective which is elaborated upon in this paper, and the term psychosocial stress is used to differentiate a more psychosocral interpretation of stress from its original definition. t The term ‘illness’ is used in this paper to describe physically manifested. or somatic, medical problems, including symptoms and diagnoses. 155
The perspective of this paper is one that had been detailed elsewhere, in which psychosocial stress is viewed as a dynamic phenomenon involving a series of stages [5]. These ‘stress stages’ involve an environmental stimulus (i.e. objective stress) which is perceived by an individual as threatening to self identity (i.e. subjective stress). In response to such a threat an individual undergoes certain organic and psychological changes (i.e. stress response or strain). Dependent on the individual’s ability to cope with the particular threat, certain consequences are possible with respect to psychological and physical health. METHODOLOGICAL
ISSUES IN STRESS
RESEARCH
Methodological problems in stress research have hindered a determination of the nature of causal re~ationships between psychosocial stress, illness, and illness behavior (i.e. behavioral responses to symptoms with respect to seeking medical care). At least 5 possible relationships can be considered: (a) psychosocial stress causes illness: (b) illness causes psychosocial stress: (c) psychosocial stress and illness are interdependent such that either one can cause and reinforce the other; (d) psychosocial stress causes certain illness behaviors and not illness (e.g. greater awareness of symptoms and likelihood of consultation with a physician); (e) psychosocial stress causes certain illness behaviors (e.g. psychosocial stress results in delayed seeking of medical care for minor symptoms) which in turn causes more serious iilnesses. The difficulty of untangling the web of causality has its roots in the implementation of certain research designs. The majority of stress studies. for both ethical and practical reasons, employ retrospective or casecontrol designs in which the subjects of the research have a particular illness or illnesses and an attempt is made to measure prior psychosocial stresses. Such designs, based on recall, have the difficulty of proving. conclusively, that psychosocial stress predates onset of the symptoms of the illness. Also, many studies, for practicaf purposes, focus on clinical populations which have seiected themselves from a ~pulation at risk. not only on the basis of illness. but also a variety of psychosocial considerations. Consequently. diagnostic information from the medical record may reflect simply behavioral patterns rather than patterns of morbidity. Moreover, many of these studies focus on the population of a particular clinic, and, as such, may give a highly distorted view of even the character of all those who seek help. To determine findings which are generalizeable, studies “require reliable and valid measurement of the dependent variable. a sizeable representative sample of persons suffering from the condition under the study, and a revelant comparison group” [6].
* The use of diagnostic checklists. and the definition of these diagnoses according to ICHPPC. provide an objective framework for the recording of data by different providers. although. ultimately, the subjective nature of the diagnostic p:actice of physicians must be acknowledged.
In examining the association between psychosocial stress and illness, the authors have attempted to satisfy the above criteria as much as possible. MATERIAL
AND METHODS
Data for the study are drawn from 1 year’s (July 197%June 1979) clinical data at 4 family health centers affiliated with the Family Practice Residency of Massachusetts Medical Program, University Center. Worcester. Two of these centers are located in the city of Worcester (population approximately 175.000) and are within 5 miles of the Medical Center. The third facility is situated in a rural town (population approximately 3ooO). some 25 miles from Worcester. Each of these 3 health centers is involved in training Family Practice residents. The fourth center. which did not train residents during the study year, is located in a city of approximately 80,000 people. 30 miles north of Worcester. Throughout the study period, there were 13 staff physicians and 3 1 Family Practice residents providing care at these 4 centers. Data for each of their encounters during the study year were entered into a computer housed within the Medical School. An audit of billing records at each health center indicated that 98”,, of all patient visits to the health center had encounter forms completed appropriately and entered into the computer. The number of encounters computerized during this period was 58,862 at all 4 health centers, for over 21.000 patients. The majority of patients visiting were female (571,,), and the largest proportion of patients were concentrated in the younger age groups (28”. under I5 years. 24”,, between 15 and 24 years, 17”,, between 35 and 34 years, and less than 8”,, over age 65). Data recording is facilitated by the use of check-list encounter forms which are precoded. using the International Classification of Health Problems in Primary Care (ICHPPC), [7]* and filled out by health center providers. The psychosocial and stress-related problems to be used as indicators of psychosocial stress in this study are classified as ‘Mental Disorders’ and ‘Social. Marital, Family Problems and Maladjustment’ in ICHPPC. The computerized encounter form data pertaining to the above diagnoses were found to have the same degree of reliability as the medical chart, the tr~~ditionally accepted source of much clinical research. In a I”,,, random sample of all patient encounters in the study period, the proportion of all psychosocial problems, omitted from the computer but present in the medical chart. was found to be equal to the proportion of all such diagnoses omitted from the medical chart but recorded on the computer (i.e. 17”,,). [S]. For the purposes of this paper 4 specific diagnoses were selected from the psychosocial category in ICHPPC. as indicators of psychosocial stress. The choice of the diagnoses was based on a desire to be consistent with a concept of stress which is multidimensional. involving both env~ronmen~~i stressors and emotional stress responses. The preceded diagnoses of anxiety and depression (ICHPPC codes 3000, 3004) were used as indicators of emotional stress, and couple conRict and child abuse and neglect (ICHPPC codes 1084, 1085) were used as indicators of environmental stressors. Child abuse and couple conflict
Psychosocial
stress and illness
conceivably, be considered as indicators or symptoms of psychosocial stress. Their inclusion as environmental stressors is based on the fact that they define pathological family situations or envjronments and the likelihood that both problems will cause or exacerbate emotional stress in family members. A ‘case-control’ research design was adopted for the study. Morbidity profiles were compared for stressed patients (‘cases’) and nonstressed patients (‘controls’) within the study population. Subjects were selected from a clinical population and, as such. are a selfselected group which might not represent the general population. The inclusion in the study, however, of 4 clinical sites, variously located with diverse patient characteristics (e.g. rural versus urban, small town versus large town, primarily Medicaid at one site and primarily Blue Cross at another site) suggest that reported findings are widely generalizeable. could,
R~seurch yuestiom Specifically, the research is designed to: (1) investigate the relationship of psychosocial stress (considered as both an environmental stressor and emotional stress) to somatic health problems (i.e. illness); (b) examine the relationship of psychosocial stress to illness behavior; (c) consider the role of stress on the general or specific nature of illness susceptibility. Again, the emphasis of this report is not on catastrophic illness, as is generally considered in the literature, but physically manifested illnesses encountered commonly by Primary Care physicians.
In the first phase of the study, psychosocial stress was defined as an emotional stress. The prevalence of the ‘most common’ somatic symptoms and diagnoses was determined for the two groups of ‘cases’, i.e. separately, for patients who were diagnosed with anxiety or depression (the 2 chosen indicators of emotional stress). Any somatic problem which occurred in at least 5”;, of the cases was included in the analyses. Comparisons were made with the prevalence of the same somatic conditions in the rest of the patient population (‘controls’) by calculating a standardized morbidity ratio (SMR)* for each associated health problem among anxiety patients (N = 191) and among depression patients (N = 356). In the second phase of the study. psychosocial stress was defined as an environmental stressor, and the prevalence of the most common somatic conditions was determined for the two groups of ‘cases’: i.e. separately, for patients with each of 2 famiiy problems, couple conflict (N = 238) and child abuse/neglect (N = 194) the chosen indicators of environmentai stressors. Any somatic problem which occurred in at least 551;,of the cases was included in the analyses. Comparisons were then made with the prevalence of * Using all health center patients as the standard population and the indirect method of adjustment. the age-sex specific prevalence rates of a given somatic problem were applied. separately, to the age-sex distribution of anxious and depressed patients, to obtain an expected prevalence rate for both groups. A standardized morbidity ratio was then calculated for each group of anxiety and depression patients, i.e. the observed prevalence divided by the expected prevalence during the study year.
157
the same health problems in the rest of the patient population (‘controls’) using the above method of age-sex standardization. For each of the 4 case groups and their respective controls, either the normal or Poisson distribution was applied to the illness occurrence data (depending on the magnitude of the expected frequency of illness) to test for significant differences in illness occurrence between the stressed and nonstressed groups. RESULTS
As Table 1 indicates, after adjusting for sex-age differences between anxiety patients and the total patient population, and based on the normal or Poisson distribution, the observed prevalence rates of some of the physical problems associated with anxiety patients were significantly higher than the expected (i.e. cystitis. arrythmias, chest pain. abdominal pain, hypertension, headaches, acute bronchitis, dizziness, weight loss, and warts.) Table 2 demonstrates higher than expected prevalence rates of certain somatic complaints associated with depression patients (i.e. chest pain, boil/cellulitis. abdominal pain, low back pain, headache, vaginitis. obesity, hypertension. dizziness. osteoarthritis and malaise/fatigue). One could argue that the higher than expected prevalence rates of the above somatic problems in patients who are anxious or depressed is attributable to an increased tendency to make more visits for health care. since the probability that a patient will be diagnosed with any of the illnesses in Tables 1 or 2 is. among other factors. related to the number of visits made for health care (i.e. illness behavior). Depressed and anxious patients did make significantly higher (P < 0.001) Table
numbers
of visits,
1. Reiatjonship
on average,
between
anxiety
(5.5 and
5.4
and illness Standardized Morbidity Ratio?
Acute upper respiratory infection Hypertension Abdominal Pain Vaginitis Acute Bronchitis Obesity Cystitis. urinary infections Diabetes mellitus Arrythmia Dizziness, giddiness Chest pain Wetght Ioss Osteoarthritis Low back pain Headache Warts
1.39 1.96*** 2.41***
1.25 1.75** 1.10 3.58*** 0.79 4.!%*** 3.54*** (X19***
11.Yi*** 1.11 1.20 1.93* 4.69***
*** P < 0.001. ** P < 0.01. * P < 0.05. t SMR = .stcdurdixd
nmhidity rutio of observed to expected prevalence of illness among anxiety patients during year. age-sex adjusted by indirect method. The SMR compares the illness prevalence between anxiety patients and all other patients.
158
MKXAEL A. GODKINand
respectively) than non-depressed and non-anxiety patients (2.6 in both cases). However, since comparisons of the prevalence of problems between stressed and nonstressed groups were based not on frequency data alone, but on standardized, expected frequencies using the illness prevalence rates of the patient population, this argument is not valid (the prevalence rate of a particular illness in this context indicates the percentage of the total number of illnesses that is constituted by that illness). It follows that the proportion of the total illnesses accounted for by a particular illness should be equal for both stressed and non-stressed groups if the 2 groups actually have the same morbidity profiles, regardless of their unequal visit rates. However, these data reveal that many rates of illnesses were significantly higher for the stressed group. These findings would suggest, then, that the differences in prevalence rates reported in Tables 1 and 2 are not dependent upon the number of visits made by anxious or depressed patients, It is interesting to note that many of the illnesses significantly associated with anxiety and depression are common to both (i.e. abdominal pain, chest pain, headache, hypertension and dizziness). It is also noteworthy that a number of illnesses are more characteristic of depression patients than anxiety patients (i.e., obesity, low back pain, osteoarthritis, and vaginitis) and of anxiety patients than depressed (bronchitis, arrythmias, weight loss, warts.) It appears, then, that anxiety and depression increase the general susceptibility to illness rather than being related to one particular illness. However, the data indicate that there may be some specificity with respect to the types of illnesses that are induced by different forms of emotional stress. Although many illnesses associated with anxiety or depression are common to both, certain illnesses are more specific to either anxiety or depression.
Table 2. Relationship
between
depression
and illness
Standardized Morbidity Ratio? Hypertension Obesity Osteoarthritis Low back pain Acute upper respiratory Abdominal pain Headache Chest pain Malaise, fatigue Acute bronchitis Diabetes mellitus Dizziness, giddiness Vaginitis Boil, cellufitis
infection
1.49** 1.96** 2.57*** 2.64*** 1.17 2.25*** 3.28*** 8.52”* 3.34*** 1.20 1.36 2.95*** 2.21*** 3.16***
*** P < 0.001. ** P i 0.01. t SMR = standardized morbidity rutio of observed to expected prevalence of illness among depression patients during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between depression patients and all other patients.
CINDY A. RICE
Table 3. Relationship
between
couple
conflict
and illness
Standardized Morbidity Ratio? Acute upper respiratory Obesity Abdominal pain Headache Acute bronchitis Hypertension
infection
1.10 2.19***
I x0*** 2.70*** 2.16*‘* 7.x2***
*** P < 0.001. t SMR = srandardized morbidit), rurio of observed to expected prevalence of illness among patients with couple conflict during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between ‘couple conflict’ patients and all other patients.
Psychosocial stress as e~~ir(~~rnel~t~l~ stressor From a perspective of stress as an environmental stressor, analyses using either the normal or Poisson distribution indicated a significantly higher prevalence of illnesses among patients with family problems, than would have been expected on the basis of the rates of the same diagnoses in the total patient population. The prevalence rates of headaches. abdominal pain, obesity, bronchitis and hypertension were significantly higher in patients with couple conflict recorded compared with the rest of the patient population (see Table 3). Patients with recorded abuse or neglect had significantly higher than expected rates of bronchitis. abdominal pain, acute URI, viral infections, and obesity compared with the rest of the patient population (Table 4). As argued earlier. the use of rates in the analyses means that these differences are not attributable to significant differences (P -C 0.001) in utilization rates between patients diagnosed with couple contfict (5.0 visits, on average) or child abuse (5.2 visits) and patients with neither couple conflict (2.6 visits) nor child abuse (2.6 visits) problems. Table 4. Relationship
between
abuse,‘neglect
and illness Standardized morbidity Ratio?
Viral infection Acute upper respiratory Acute bronchitis Abdominal pain Obesity Acute otitis media
infection
5.31*** 1.87* 2.07”s 1.7* I .46* I.05
*** P < 0.001. * P < 0.05. 7’ SMR = .standardi;ed morbidit~~ rutio of observed to expected prevalence of illness among patients with abuse,’ neglect during year, age-sex adjusted by indirect method. The SMR compares the illness prevalence between ‘abuse.: neglect’ patients and all other patients. CONCLUSION
The data presented in this study lend support to the existence of a relationship between psychosocial
Psychosocial
159
stress and illness
stress, viewed either as an environmental stressor or as an emotional stress, and illnesses encountered commonly by Primary Care physicians. The data do not the direction of causality establish, definitively, between psychosocial stress and illness: a more sophisticated and time-consuming prospective study involving survey techniques is necessary to establish the nature of causality. Strong evidence is provided, however, which supports a hypothesis that psychosocial stress leads to illness rather than vice-versa. The examination of the multi-dimensional nature of stress and, in particular. considering stress as a stimulus would appear to provide considerable support for such a hypothesis. It is highly unlikely that the physical problems associated with family problems are, in fact. the cause of such problems. It is much more likely that the familial problems. themselves. lead to the onset of illness and manifestation of physical symptoms. There are significant differences in the numbers of visits made by stressed and non-stressed patients but these differences do not account for the higher rates of illnesses in the stressed groups. Further studies, using different research methodologies, are needed, however, to determine whether the morbidity data presented in this paper reflect the existence of clinically verifiable somatic problems. It may be that the diagnosed somatic complaints represent, simply, patients’ experiences of physical discomfort because of heightened awareness of body functioning and lower pain thresholds in periods of stress, as in hypochondriacal behavior. Finally, the evidence in this paper
indicates that psychosocial stress increases an individual’s general susceptibility to illness, and that certain stressors and emotional stresses appear to be specific to certain diagnoses.
REFERENCES
1. Kanner A. D.. Coyne J. C., Shaefer C. and Lazarus R. S. Comparison of two modes of stress measurement:
2. 3.
4
5.
6 7.
8.
daily hassles and uplifts versus major life events. Forthcoming in J. Behac. M. Holmes T. H. and Rahe R. H. The social readjtistment rating scale. J. Psychosom. Rrs. 2, 213, 1967. Lazarus R. S. Cognitive and personality factors underlying threat and coping. In Psychological Stre.s.s (Edited by Appley M. H. and Trumbull R.), pp. 151-157. Wiley, New York, 1974. Arnold M. B. Stress and Emotion. In P.s~~cho/oyicul Srre.ss (Edited by Appley M. H. and Trumbull R.), pp. 123-140. Appleton-Century-Crofts, New York. 1967. Cobb S. A model for life events and therr consequences. In Strvssfil Lifr Ecents (Edited by Dohrenwend B. S. and Dohrenwend P. B.). pp. 15 1-I 57. Wiley, New York, 1974. Mechanic D. Stress. illness and illness behavior. J. hum. Stre.ss 2, 5. 1976. World Organization of National Colleges, Academies. and Academic Associations of General Practitioners.: Family Physicians. Intrrnationul Classificurion ctf Hrulfh Problems in Primur~~ Cure. American Hospital Association, Chicago, 1975. Rice C., Godkin M. and Catlin R. J. 0. Methodological. technical and ethical issues of a computerized data system. J. Fam. Prucf. 10, 665, 1980.