The psychological aspects of essential hypertension

Journal oj Psychosomatic Printed in Great Britain.

Research,

Vol.

30,

No.

5 pp.

527-541.

1986 0

INVITED THE PSYCHOLOGICAL

1986

OOZZ-3999/86 $3.00 + Ml Pergamon Journals Ltd.

REVIEW ASPECTS

OF ESSENTIAL

HYPERTENSION ANTHONY

H.

MANN

(Received22 May 1986)

INTRODUCTION IT IS SALUTARY to

start by noting that psychological factors must be currently classed as an also ran in the aetiology of essential hypertension and of cardiovascular disease in general. This lack of importance for psychological factors stands out, bearing in mind that clinicians since earliest times have observed that strokes and heart attacks often occur at times of high emotion. Further, it is now 50 years since Franz Alexander [l] proposed an immediately attractive hypothesis that linked emotional state and hypertension. ‘The hypertensive individual has been described as one with inhibited and poorly expressed rage and anger. It has been suggested that this inhibited rage, or anger, expresses itself in stimulation of the autonomic nervous system with the release of significant amounts of norepinephrine leading to acute and eventually chronic hypertension’ [2]. Two hypotheses are here contained: (a) that a behavioural attribute is expressed in physical changes and (b) that a repeated acute change in physical state would eventually cause a chronic state. The large volume of work that has followed this original formulation has failed essentially to substantiate these theories so far. The failures could however have stemmed from methodological inadequacies rather than falsity of basic ideas. For instance, the basic hypothesis of Alexander which borrows mechanisms from psychoanalytic theory is difficult to test scientifically, usually studies have superficial measures of psychological and social state, the studies are often on small selected samples of hypertensive patients and there has been a naivety about the nature of hypertension itself. Despite many inconclusive results, however, it is remarkable that so much research has persisted, perhaps a reflection of the increasing importance accorded to even mild levels of raised blood pressure in the causation of stroke or heart attack, the lack of a total organic explanation for the cause of hypertension and, tantalizingly, the discovery that behavioural therapy can be successful in controlling blood pressure level in some subjects. Before reviewing some of the main themes in these last. decades of research, the perspective must be set by defining hypertension in modern terms and describing some non-psychological factors that are now known to have a harked impact on blood pressure levels. The psychological research, which normally investigates small samples of subjects, must be assessed against this broader background.

Royal Free Hospital, Hampstead, London NW3 2QG, U.K. 521

ANTHONY H. MANN

528 ESSENTIAL,

LABILE

AND

BORDERLINE

HYPERTENSION

Blood pressure levels are normally distributed in a population. Thus the definition of hypertension is inevitably arbitrary, the critical levels being selected because of increasing risks of subsequent morbidity; the World Health Organisation classifying levels of 160/95 mm Hg as definitely hypertensive. However, current methods of 24 hour continuous monitoring of blood pressure level have revealed that for all individuals, hypertensive or not, there is considerable daily fluctuation in blood pressure level, falls of 40-70% from the maximal level of systolic and diastolic pressure being recorded. Younger individuals have much greater variability than older. This variability of daily blood pressure level has important implications for research, for it may be that some psychologically orientated studies are really investigating a relationship between psychological factors and variability of blood pressure levelor cardiovascular responsiveness-rather than with changes in basic level of pressure. Although it may be interesting to show which psychological factors caused marked changes in blood pressure level, the evidence linking variability to subsequent physical morbidity is not established [3]. The World Health Organisation classes blood pressures as normal at levels below 140/90 mm Hg. The range in between the normal and hypertensive is called borderline. It had also been noticed that blood pressure levels can, in some, fluctuate in and out of the hypertensive range, these subjects being called the ‘labile’ hypertensives. However, as there is variability at the borderline level as with normal subjects, a considerable overlap between subjects called borderline and subjects called labile is inevitable. The term ‘labile’ is falling into disuse. Subjects with borderline levels are often chosen for psychological research for it is thought that these are in a prehypertensive phase and that the structural changes in the vascular tree, adaptations to persistent high levels, will not have occurred so that the direct effect of the autonomic system can be observed. However the majority of subjects with borderline levels of elevated blood pressure do not subsequently become definite hypertensives 141, thus findings may not be relevant to essential hypertension. FACTORS

AFFECTING

BLOOD

PRESSURE

LEVELS

AND

MEASUREMENT

Mean base levels in populations are influenced by various factors. Most important is the effect of age upon the systolic and diastolic levels-there may be up to 40 mm Hg increase between the ages of 10 and 70 in systolic blood pressure. However, this age related rise has been shown not to occur in populations living isolated from Western culture, implying that it is not inherent but may reflect aspects of life stylediet or cultural stress. Blood pressure levels are also affected by obesity-201b extra weight being equated to a 4 mm Hg rise in systolic blood pressure. There is too the influence of inheritance, which is thought to be of polygenic mode. Blood pressure levels in the first degree relatives of hypertensive patients tended to be higher than the mean in the population at large. Alcohol has long been known to affect level of blood pressure independently of any of the above factors. Every 10 mg of alcohol consumed per day regularly is associated with 1 mm Hg rise in systolic pressure. Finally exercise as a regular activity is now known to lower blood pressure level. Thus these five factors, age, obesity, family history, alcohol and exercise, must all be borne in mind when selecting subjects and controls for a study of yet other factors-in this case psychological ones-in hypertension.

The psychological

aspects

of essential

hypertension

529

The measurement of blood pressure needs particular attention in all experimental work. The random zero sphygmomanometer avoids observer bias and should now be mandatory. The effect of ambient temperature both in the external climate and in the room at the time of measurement has been demonstrated [5]. The conditions of measurement of blood pressure must therefore be standardised and reported in research studies. What might appear to be the firmer measure in the psychological-hypertension dyad need attention. Unfortunately much psychologically based research has ignored these many factors that affect blood pressure level and these factors may have influenced results. The research that has been carried out over the years will now be considered under three brc ’ groupings-those investigating the relationship of blood pressure level with exteliial stress, with personality type or behavioural trait and with psychiatric morbidity. Then the work assessing the impact of diagnosis of hypertension upon an individual will be described with the research on psychological aspects of treatment of hypertension. EXTERNAL

STRESS

AND HYPERTENSION

The term stress can be applied to the circumstances or stimuli to which an individual reacts. It can also be used to define the state of altered physiology with which the individual responds. The former category of stress is now considered. The latter is discussed in the section Psychiatric Symptoms and Hypertension. Stressful events have long been known to invoke dramatic physiological changes in both man and animal. As part of this response is a rise in blood pressure level, a reasonable hypothesis to test would be one that repeated stresses cause permanent elevation in blood pressure level. This hypothesis has been tested amongst animals to which stress can be applied in several ways-noxious stimuli, artificial interference with natural bonding and crowding. Undoubtedly some persistent changes in blood pressure level have been noted, particularly in response to crowding [6,7]. Anticipatory arousal, changes in blood pressure level occuring in advance of a noxious stimuli (that may or may not be delivered) has been also demonstrated in many experimental animals and has been hypothesised as relevant in man [S]. However it should be noted that the chronic hypertensive state involving structural change in blood vessel or end organ has not been produced in animals as a result of recurrent neurogenic stimuli [9]. In man, the equivalent laboratory studies have essentially compared the responses of normal, borderline or hypertensive subjects to various mental stresses. The purpose has been to demonstrate a greater magnitude and duration of blood pressure elevation in the hypertensive groups, to detect whether any type of stress is specifically pressor and whether there is a cumulative effect of several sequential stresses. Stresses for man can be structured tasks, with or without additional challenge for the subject, or be particular social interactions, in which the scenario is controlled by the experimenter. Brod et al. [lo] provided impetus to this work by reporting greater reactivity to mental arithmetic tests of blood pressure among hypertensives than among normotensives. However, subsequently, numerous studies have been published with less clear cut findings, these being comprehensively reviewed by Linden [l l] . It now seems clear that no specific type of stress or pattern of stresses has been demonstrated as definitely pressor for all subjects, although for any individual some stress can cause blood pressure rise. As indicated earlier, these changes may

530

ANTHONY H. MANN

reflect variability or reactivity of the cardiovascular system, not yet linked to a permanent hypertensive state. A further caveat to all this work is that the generalizability of these laboratory induced stresses to stresses of every day life has not yet been shown. The alternative approach, outside the laboratory, to assess a relationship between external stress and blood pressure level has involved the observation of populations that differed either in their experience of stress or in their blood pressure level. Such studies, natural experiments, suffer from different methodological problems from the laboratory based ones which at least can be specifically designed. For, within natural experiments, randomisation cannot occur of subjects for example into high or low stress populations, so that hidden selection factors cannot be discounted as an explanation of observed differences. This research has investigated environmental stresses upon population blood pressure levels-in particular the effect of urbanisation, conceptualised as the breakdown of the cohesion and protection of rural or more primitive societies and the substitution of crowding, poverty, crime and unemployment. Support for the pressor effect of urbanisation has come from a survey of blood pressure levels in primitive tribes and from studies of levels in urban and rural populations in countries such as South Africa, Nigeria and Kenya. It seems that remote tribes and the rural populations tend both not to show an age related rise in blood pressure and have lower mean population base levels [ 121. Migrants from primitive or rural areas to a Western urban environment have also been studied, particularly the Pacific Islanders who have emigrated to New Zealand. Compared to those remaining at home, there is evidence that blood pressure rises amongst the emigrants during the years after migration. All these population studies have recently been reviewed by Marmot [13] who himself, with colleagues, had reported findings against this general urbanisation theory when it was shown that Japanese migrants to the United States did not show the expected rise in blood pressure, although they did show higher levels of serum cholesterol and greater increases in the prevalence of coronary heart disease than did the Japanese at home. Marmot (13) speculates that changes in the cardiovascular system after migration may reflect diet or exercise rather than urbanisation. It is also to be remembered that migration is not a random event and there may be hidden selection factors amongst the migrants. Within the United States, Harburg et al. 1141showed the blood pressure levels of black residents of Detroit with high urban stress (as shown by crime statistics etc.) were higher than those in low stress areas. However this study has since been contradicted by the findings of a much larger scale cross sectional study in the United States that showed no association of sociocultural variables that would indicate ecological stress and blood pressure level [ 151. The findings of large scale population surveys that have attempted to demonstrate a relationship between urbanisation or more stressful living and blood pressure level are at best inconclusive. More specific studies have attempted to explore the relationship of occupation and of crowding to blood pressure level in man. Cobb and Rose [ 161 showed that air traffic controllers had a higher level for blood pressure than the aircraft men whose work was less mentally stressful. Such a clear cut relationship between occupation and blood pressure level has not been reported again but exposure to noise at work has been associated with elevated blood pressure [ 171. One intriguing study has followed the leads provided by the laboratory experiments

The psychological

aspects

of essential

hypertension

531

indicating the pressor effect of enforced crowding in mice. D’Atri and Ostfield [18] showed a positive correlation between crowded accommodation in prison and blood pressure levels amongst inmates. Following this cross sectional survey, D’Atri et al. [ 191 investigated in more detail the population in one United States prison where the regime was that each prisoner began their term in a single cell, but after one month could move to a dormitory or remain in single cell accomodation. During their prison term, some prisoners in either type of accommodation could leave the prison by day for work-a day release programme-but others did not. The prison population therefore could be stratified into four groups by accommodation and work. Blood pressure levels were shown to rise selectively amongst the prisoners leaving single cell accommodation for the dormitory, whereas participating in the day release programme did not affect this rise in blood pressure. All four groups had been shown to have similar blood pressure baseline levels and degree of variability, determined during the initial month’s stay in a single cell accommodation. This detailed follow up research does suggest some effect of enforced crowding upon blood pressure level in man, but there remains the possibility that there is some attribute of the hypertensive-prone prisoner that causes the prison authority to allocate him to a dormitory rather than to stay on in a single cell. However this study is impressive in that it focuses on a specific hypothesis and has overcome some methodological difficulties. In general however the case to link population pressure levels to environmental variables has not been proven. PERSONALITY,

BEHAVIOURAL

TRAITS

AND HYPERTENSION

In this area of research, the focus of the studies has shifted from the external stress itself to the individual, examining whether a particular personality type or behavioural style determines blood pressure level. No evidence has yet been presented from use of standard personality inventories that there is a particular ‘hypertensive personality’, i.e. a particular pattern of responses that identify individuals with this condition [20, 211. Cochrane [22] dismissed his own findings, that the Eysenck Personality Inventory responses differed between hypertensive patients and normotensive controls, on the grounds of the self selection of certain individuals to medical attention, a caveat that is applicable to all studies that have compared hypertensive patients with normotensive control subjects. Perhaps more fruitful have been the studies that have investigated blood pressure level in relationship to a behaviour trait-repression of hostility, impairment of social competence and Type A behaviour being examples. Alexander’s formulation (1939), quoted earlier, supposed that poorly expressed hostility finds its expression in hypertension. This theory gained considerable credence and some confirmation from specific laboratory experiments which exposed individuals to frustration in controlled circumstances where some are allowed to discharge their anger, others not. While both groups showed .elevation of blood pressure level when frustrated, in the former group the rise was much more protracted [23]. Similarly Fishman [24] found that subjects for whom the need for social approval was high, associated with a tendency to demonstrate anxiety rather than anger at times of induced frustration, were more likely to show prolonged blood pressure rises in frustration experiments compared to those without such a need for social approval. However, if hostility be measured by a clinician’s observation or by a self report questionnaire-the Hostility Direction of Hostility Questionnaire [25]-hypertensive

532

ANTHONY H. MANN

cannot be distinguished from normotensive subjects [26, 271. Mann (281 investigating subjects in the context of a clinical trial of treatment for raised blood pressure found no evidence to associate repression of hostility and blood pressure level. What was apparent was that HDHQ score changed markedly with mental state, particularly depression. In contrast to these negative finds, Cottington et al. (29) surveying a probability sample of hypertensive subjects of both sexes in Michigan found that suppressed emotion-measured by self report on an 8 item scale-to be the only independent predictor of diastolic pressure level. However the relationship although statistically significant was a weak one and, among men, there was also a weak positive relationship between self perceived psychiatric problems and blood pressure level. It is possible to speculate that once again a confounding variable, that of current mental state abnormality, has affected self report on emotional expression. The findings for this hypothesis are at best inconclusive: perhaps specific investigations that take into account the current mental state of the subjects and that analyse hostility in terms of its chronicity, intensity and expression are warranted, as suggested by Cottington et al. 1291 in their conclusions. Hypertensives are postulated as differing in their social interactions from their normotensive fellows in that they are more submissive, less likely to talk about themselves and less likely to disclose personal feelings [30]. This behaviour can be regarded as socially incompetent, leading to difficulties at times of altercation when it is associated with blood pressure rise. Many detailed small studies involving role play have compared hypertensive and normotensive subjects, since an original report suggested that hypertensive women were less skilled at handling circumstances including assertion and hostility than normotensive [3 11. All this subsequent work has been recently reviewed by Linden [l l] who concluded that the results are contradictory, perhaps explained by the fact that hypertensive subjects may not be a uniform group in respect of social competence, that social competence is a complex construct and not amenable to assessment by a simple questionnaire. He therefore calls for more specific analyses of areas in which hypertensives are said to be specifically handicapped, i.e. overadjustment, conflict avoidance and ambivalence of feeling rather than assessing social competence in general which covers many behaviours for which hypertensives are not said to have problems. Type A behaviour was described by Friedman and Rosenmann 1321as an overt style of reaction which showed some or all of the following features: time urgency, competitiveness, work involvement, intense striving for achievement, abruptness of manner of speech and tension of musculature. This form of behaviour has gained considerable notoriety and research interest since publication of evidence concerning its association with coronary heart disease, both from cross sectional surveys and in one longitudinal investigation 133, 341. However Type A behaviour, assessed by structured interview or by the responses to a self completed questionnaire, has not in surveys been associated with blood pressure level [35], but there is some evidence that Type A and non-Type A subjects differ in their responses to stress in face of cognitive tasks [36]. The former tend to show both greater and more protracted rises in systolic blood pressure than non-Type A subjects. The construct of Type A behaviour is now under critical review on the grounds that it is a complex and ill-defined construct and that most of the evidence of its potency to predict coronary heart disease comes from a study of middle class

The psychological

aspects

of essential

hypertension

533

Americans [37]. However, like the other two constructs, hostility and social incompetence described above, it would probably benefit itself from more detailed research before being promoted as an aetiological factor for aspects of cardiovascular disease. Confirmation of validity in non American cultures would be welcome for it could be that the interviews and questionnaires devised to detect this behaviour are biased by their American derivation and do not adequately assess the phenomenon outside that country. If so confirmed, Type A behaviour would seem to be a variant of coping style that is at times as inefficient for the subject as is repression of hostility or social unassertiveness, hypothesised earlier as being associated with hypertension. PSYCHIATRIC

SYMPTOMS

AND HYPERTENSION

Ayman and Pratt [38] likened the complaints of hypertensive patients to those of patients with psychoneurosis-thus beginning a stream of research that has attempted to discover an association between psychiatric morbidity and hypertension. For instance Sainsbury [39] showed that hypertensive out-patients had higher neuroticism scores than patients with other psychosomatic disorders and Robinson [40] found an association, in middle aged males, between neuroticism and hypertension in a random sample of community residents. Cochrane [27] compared treated hypertensive patients attending a general practitioner with those whose high blood pressure had just been detected. The former had higher levels of neurotic symptoms than the latter who did not themselves manifest higher levels of neurotic symptoms than normotensive patients. Cochrane therefore suggested that the high neuroticism rate amongst hypertensives could be an artifact of treatment, particularly as the drug reserpine was still being used. Kidson [20] compared psychological features among hypertension clinic attenders with subjects screened and found to be hypertensive at their place of work. The clinic attenders had many more complaints-somatic symptoms, tension and anxiety-than those detected by screening. On the surface, some of these studies indicated that hospital hypertensive patients at least seem more likely to display psychiatric symptoms than control subjects. One explanation is that there is an underlying relationship between the hypertensive state and increased prevalence of psychiatric morbidity, but it seems more probable that this association could be explained by either selection, the impact of diagnosis or the result of treatment. One selection factor is the referral procedure: symptomatic hypertensives may be referred to hospital by the general practitioner, who prefers to treat himself patients with fewer complaints, implying that symptomatic hypertensives tended to accumulate in hospital out-patients and thereby providing a biased sample for study in that area. Another selection factor is that of the physician’s choice of patients for blood pressure measurement, for many physicians believe that phenomena such as headache, dizziness or poor concentration are symptoms of hypertension, so that patients with these symptoms (which could also indicate a psychiatric disorder) will have their blood pressure checked more frequently than uncomplaining patients. As a result hypertension is more likely to be detected in patients with psychiatric symptoms. This hypothesis, discussed in a BMJ Editorial [41], has not been formally tested. Recent cross sectional surveys aiming to investigate the relationship between psychiatric symptoms and hypertension have assessed whether patients were aware of their own hypertension and whether or not some form of treatment was underway. For instance, the United States Health and Nutrition Education Survey of nearly 4,000 adults

534

ANTHONY H. MANN

involved the completion of an 18 item well-being questionnaire as well as enquiry into medical history and examination [42]. From this survey, the subjects identified as hypertensive were classified as aware if they reported that they had been told of their high blood pressure by a physician or if they had previously taken pills for the condition. In general, the surveyed adults who were hypertensive showed no difference in well-being scores from the normotensive. However, among the hypertensive subjects, those who had been previously informed and treated for the hypertension appeared to have worse well-being scores than the uninformed. In another state, 52,000 patients of a health care programme in California received a medical check up and completed a five point psychological status questionnaire adapted from the Cornell Medical Index 1431. Four groups were identified: those with high blood pressure at examination and previously aware, those with normal blood pressure but who had some information that it had been earlier raised, those with high blood pressure but with no previous knowledge and those with normal pressure at screening. No difference in psychological status score was detected between normotensives and hypertensives but both the ‘aware’ groups, whether or not their current pressure was raised, exhibited more psychological symptoms than did the unaware. Both these two surveys can be criticized because of their superficial measure of psychological status but both suggested that being aware or treated for hypertension was more associated with impairment of psychological status than being hypertensive. The psychological effect of diagnosis and inclusion into a clinical trial of treatment of hypertension was specifically examined in a sub-study of the Medical Research Council Trial for mild to moderate hypertension 144,451. For the sub-study 12 693 subjects who attended for screening at nine pilot clinics of the trial completed the General Health Questionnaire [46] before blood pressure measurement was taken, the patients being therefore unaware of their own levels. After completion of the questionnaire, the subjects’ blood pressure level was measured for purpose of entry in the MRC Trial and those with diastolic pressure of above 90 mm Hg-representing about 10% of the total screened population between 35 and 64-were recalled for further measures. In about half, the pressure settled to normal level on subsequent examination while the remaining subjects were asked to participate in the trial itself. The GHQ score could be later compared amongst the three groups: subjects with normal blood pressure, subjects with a temporary elevation of blood pressure and subjects with a persistent elevation. No significant differences were found in the distribution of GHQ scores amongst the three groups and no relationship between GHQ score and blood pressure level was discovered when both were analysed as continuous variables. This large scale study then, using a well validated questionnaire, implied quite strongly that hypertensive subjects unaware of their blood pressure level did not significantly differ in psychiatric symptom state from the normotensive population.

IMPACT

OF DIAGNOSIS

OF HYPERTENSION

The evidence in the previous section would suggest that any excess of psychiatric morbidity amongst hypertensive subjects is not part of the hypertensive state but follows upon diagnosis. This diagnosis, as with any, is ‘labelling’, understood as the conveyance of information to an individual that he is suffering from disease and an awareness on the part of the recipient that labelling has occurred. Within psychiatry

The psychological

aspects

of essential

hypertension

535

labelling has become a concept for a theory of mental illness but, for public health physicians, it is an inevitable day to day consequence of screening subjects with a view to early detection and treatment of a physical disorder such as hypertension. The potential import of even mild degrees of hypertension for the health of a population has lead to a considerable energy in the last ten years being devoted to screening programmes, but accompanied by expressed concern that many individuals might be made unduly anxious by this activity. Another consequence of identifying an otherwise healthy subject as potentially ill (hypertensive) is that it provides the recipient the opportunity to take up the sick role [47]. The sick role is one in which the person who takes it on becomes exempt from responsibility for his or her own incapacity, obtains relief of normal social role obligations, must see his or her condition as undesirable and must seek competent help. Screening programmes with a result that imposes the diagnosis of hypertension may therefore have adverse psychological impact as a consequence of labelling and a behavioural effect in that the individual may choose to take up the sick role. One factor that may modify these two consequences is the cultural belief of the group, to which the new hypertensive belongs, about the nature of hypertension. Some information in this area has come from the US National Institute of Health Survey [48] that indicated that the majority of respondents regarded high blood pressure as a severe condition associated with worry and was stress-induced. Blumhagen [49] studied the attitude of 103 male hypertensives who had received standard medical explanations of their disorder. Blumhagen found later that these subjects perceived hypertension as a different state from high blood pressure, the former being a state characterised by nervousness, fear and anger induced by stresses particularly at work. Some individuals, it appeared, then proceeded from this state of hypertension to develop high blood pressure which was responsible for physical symptoms. This separation of the concepts of hypertension and high blood pressure in no way matched the earlier medical explanation. Societies can impose handicap for the hypertensive in terms of employment opportunity at least in the United States [50]. Surveyed firms made it plain that blood pressure determined rejection for employment-not because of the possibility of absenteesism, but because the company may become liable for any events such as stroke or infarct that migh overtake the hypertensive employee while at work. It would not be surprising therefore, within the United States at least, that the label of hypertension might cause subjects to re-evaluate perceived stresses, particularly at work. Consequent difficulties with employment and perhaps life insurance in fact encourage an individual to adopt the sick role. Specific follow up research assessing the actual impact on individuals of screening for hypertension has largely been carried out within North America. Haynes et al. [51] produced an alarming result that absenteeism increased amongst subjects screened and identified as hypertensive at their work site. Subjects previously aware of their hypertension did show higher absentee rates than their normotensive workmates, but the newly aware showed a trebling in absenteeism during the period after detection. All identified subjects were referred to their own physicians for treatment and there was no relationship of absenteeism as to whether or not they were subsequently treated. On the same subjects, Mossey [52] reported a lowering of self esteem and a decrease in a sense of marital adjustment. These alarming findings from Canada were partly confirmed by studies in the United States where Alderman [53, 541 conducted on-site

536

ANTHONY H. MANN

screening among employees of a department store and then an insurance company. These projects, however, differed in that employees were offered on-site follow up after screening. A change in absenteeism was noticeable only amongst new hypertensives that did not elect for on-site follow up. In the United Kingdom, the Medical Research Council in the pilot phase of its treatment trial of mild to moderate hypertension determined to investigate the psychological effect of diagnosis and inclusion in a clinical trial, particularly in view of the worrying findings emerging from North America [45]. 235 newly labelled and recruited trial entrants were followed up for one year and matched by age, sex and initial psychiatric state with two control groups, one who were entirely normotensive and one who had been found initially at screening to be hypertensive but whose blood pressure had subsequently settled and so were not suitable for the trial. The first group were thus both labelled and included in a treatment trial, the third group were labelled only while the second group were neither labelled nor in the trial. This research demonstrated no differences in psychiatric morbidity assessed by responses to GHQ and standard psychiatric interview after labelling. Further, during the first year on the clinical trial, the prevalence of psychiatric morbidity appeared to fall amongst the treated trial entrants compared to the two control groups. This surprising finding was found not to be an artifact of bias or selection, but appeared to be a response to the regular supportive contact during the year of the trial with the clinic nurses who were supervising the regime of the trial. These MRC Trial results have been discussed in conjunction with North American findings [55]. It seems possible to conclude that labelling of hypertension may induce adverse psychological and/or behavioural changes, but that these changes could be prevented if the newly detected subject be provided with regular supportive follow up. Those studies which showed adverse changes of behaviour were those where it was left to the subject to find his or her own follow up. This conclusion is important, for it puts upon those planning new screening programmes for hypertension the responsibility for supervision and follow up during the months after detection. PSYCHOLOGICAL

ASPECTS

OF TREATMENT

Commonly used pharmacological agents for the control of hypertension are known to generate psychiatric symptoms as side effects. This significant association was first reported between the rauwolfia alkaloid group, particularly reserpine, and depressive reactions and suicide [56, 571. This discovery however had a fortunate outcome, as it was in part responsible for the catecholamine theory of depression, in turn leading to the development of antidepressant medication. While reserpine is not now widely used, methyldopa with a similar pharmacological action, is still popular. Bant [58] analysed the association of this drug with depression, showing that any increase in depression after use of the drug was explained by relapse of subjects with a past history of depression rather than from new attacks. Beta blocking agents now the first choice for many hypertensive patients, are known to cause fatigue, insomnia, nightmare and occasional pyschotic illnesses [59]. Despite these specific relationships, it seems probable that all agents that lower blood pressure are capable of causing the subject distressing symptoms from postural hypotension, impotence or fatigue. These side effects, arising in previously asymptomatic subjects, may be associated with secondary anxiety or depression, leading to an apparent ‘psychiatricness’ of a treated hypertensive

The psychological

aspects

of essential

hypertension

531

population. Well designed surveys do not find any specificity of symptom state with an antihypertensive regime [6, 611. There is therefore a danger that investigations may over-include certain symptoms as ‘psychiatric’ in studies of the psychiatric status of treated hypertensives. An important development in the last twenty years has been the application of techniques of biofeedback and relaxation to the management of hypertension. The former technique requires special equipment to monitor fluctuation in a subject’s blood pressure level and to present continuous blood pressure information by use of polygraph, sound frequency or by actual number to the subject. Normotensive subjects by means of feedback have been shown to gain ‘blood pressure control’ after a few hours practice [62]. Relaxation techniques require no such special equipment; instead a quiet environment, a training to lower muscle tension and encouragement to empty mind of anxious thought with or without special aids-the mantra (transcendental meditation) or specific breathing exercises (yoga). Most of the research reports investigating both techniques in hypertensive subjects have been on small numbers and often uncontrolled (see review by Linden, [l 11). However Pate1 has now published several controlled studies of relaxation with and without feedback using drug-treated subjects as controls with apparent benefit for the experimental group even at nine month follow up [63,64]. Scepticism remains however about the scientific worth of much of the work so far published that claims the effectiveness of these psychological techniques [65]. Even if the evidence is accepted, questions remain as to the generalisability of such techniques, as to whether the real benefit is to borderline rather than established hypertensive subjects and whether any benefits obtained in the short term can be maintained over the long term. The failure of the MRC Trial to detect benefit from medication in the reduction of morbidity amongst middle aged subjects of both sexes, suffering from mild to moderate hypertension, from pharmacotherapy is likely to direct further energy to nonpharmacological treatments however [66]. PSYCHIATRIC

ASPECTS

OF HYPERTENSION

IN OLD AGE

As systolic and diastolic pressures rise with age, the elderly population is increasingly at risk from a stroke or myocardial infarct as a result of increasing numbers having a blood pressure level in the hypertensive range [67]. There is, as well, a separate group amongst the elderly of those with isolated systolic hypertension, characterised by a marked distance between an elevated systolic level and the relatively normal diastolic level. Isolated systolic hypertension presents risk for cardiovascular events and presents problems for treatment, as often the pharmacological agents required to bring down the systolic level cause marked postural hypotension, presumably because the diastolic level falls too. A further association of hypertension in old age is arteriosclerotic dementia from progressive cerebral damage from impairment in flow in the cerebrovascular tree. The precise relationship between hypertension and dementia is not clear [68]. Nevertheless the clinician can be faced with a dilemma on discovering mildly elevated blood pressure in an elderly subject with some signs of cognitive impairment. Should treatment, with its attendant side effects from the medication itself and from postural hypotension, be instituted to prevent further deterioration in cognitive function and reduce the chance of myocardial infarction or stroke? Some evidence to weigh against treatment was provided by Wilkie and Eisdorfer 1691 who showed,

538

ANTHONY H. MANN

after following up elderly subjects with differing levels of blood pressure and measuring cognitive state by responses to an IQ test, that mildly elevated levels of blood pressure protected the brain from impairment. This issue, whether or not to treat mildly elevated hypertension in patients with some evidence of cognitive impairment, is becoming pressing as the burden from dementia becomes clearer among Western populations, where extreme old age is becoming commoner. The Medical Research Council has instituted a specific sub-study of cognitive function in its large scale current treatment trial of hypertension in the 65-74 yr old age band. This sub-study may provide some useful data over the long term on the advantages or disadvantages in treating hypertension in an older age group. CONCLUSIONS

This review has attempted to cover the main themes of research that have linked psychological research to hypertension. Certain conclusions may be proposed in the current state of knowledge. (1) Psychological factors, compared to other environmental and demographic factors, have not been shown to play a convincing part in the aetiology of sustained essential hypertension. (2) Psychological factors, particularly when represented as stresses in laboratory experiment, do alter blood pressure levels. However much of this research measures the cardiovascular responsiveness or variability of blood pressure and is often conducted in subjects with a base level at borderline level of hypertension. The evidence relating either the variability of blood pressure or borderline level of hypertension to chronic essential hypertension is not conclusive. (3) Behavioural attributes such as social incompetence and repression of hostility cannot be dismissed entirely as irrelevant to the understanding of cardiovascular responsiveness. However, much more detailed work is necessary to analyse these behavioural attributes before satisfactory studies can be devised to clarify any association between such behavioural traits and essential hypertension. (4) Any apparent ‘psychiatricness’ of hypertensive populations seem to reflect the impact of diagnosis or the side effect of pharmacological treatment. Adverse social or psychological changes after the labelling of hypertensive patients may well be prevented by supportive follow up. (5) Control of blood pressure can be obtained by techniques derived from behavioural psychology. However the practicality of this benefit for the population at large and the durability of this benefit have yet to be shown. Sir Aubrey Lewis (70) described the term ‘psychosomatic’ as one that referred to ‘an ill-defined area of illness with constantly changing boundaries, in which there are manifest relationships between events best studied by psychological methods and events best studied by physiological methods’ [701. Later in the same paper Lewis commented that the life of such a term should be transitory as it ‘only reflects a muddled phase of specialised ignorance’. Despite 50 years of research the term ‘psychosomatic’ is still current in the understanding of hypertension and we remain ignorant of the precise interactions of psychological events and physical events. Yet 50 years have not been entirely wasted and the continuing importance of even mild levels of hypertension to general public health means that research will continue. It is probable that the answers for those interested in the psychological component of this research will have to wait

The psychological

aspects

of essential

hypertension

539

upon further understanding of the nature of hypertension itself. Is it an end state reflecting several aetiological pathways or a unitary process? Is it possible to distinguish borderline hypertension from moderately elevated levels that presage essential hypertension? REFERENCES 1. 2. 3. 4. 5. 6. 7. 8.

ALEXANDER

F. Emotional

SHAPIRO

. Psychophysiologic

AP

factors in arterial hypertension. mechanisms in hypertensive

Psychosom Med 1939; 1: 175-179. vascular disease. Ann Intern Med 1960;

53: 64-83. WEDER AB, JULIUS S. Pressure variability and hypertension. Psychosom Med 1985; 41: 407-413. JULIUS S, SCHORK MA. Borderline hypertension-a critical review. J Chron Dis 1971; 23: 723-754 BRENNANPJ, GREENBERG G, MIALL WE, THOMPSONSG. Seasonal variation in arterial blood pressure. Br Med J 1982; 285: 919-923. HENRY JP, MEEHAN JP, STEPHENS PM. Use of psychosocial stimuli to induce prolonged systolic hypertension in mice. J Psychosom Med 1967; 29: 408-432. HALLBACK M. Consequences of social isolation on blood pressure, cardiovascular reactivity and design in spontaneously hypertensive rats. Acta Physiologica Stand 1975; 93: 455-465. COHEN DH, OBRIST P. Interactions between behaviour and the cardiovascular system. Circulation

Res 1975; 37: 693-106. 9. 10.

11. 12.

TALMEN W, ALONSO D, REIS D. Chronic lability of arterial pressure in rats does not evolve into hypertension. Clin Sci 1980; 59: 405-407. BROD J, FENCL V, HEJL Z, JINKA J. Circulatory changes underlying blood pressure elevation during acute emotional stress (mental arithmetic) in normotensive and hypertensive subjects. C/in Sci 1959; 18: 269-279. LINDEN W. Psychological Perspectives of Essential Hypertension. Karger Behavioural Medical Series, No. 3, 1984. Base]: Karger AC. SHAPER AC. Cardiovascular disease in the tropics:-III. Blood pressure and hypertension. Br Med

J 1972; iii: 805-807. 13. 14. 15. 16.

MARMOT MC. Geography of blood pressure and hypertension. Br Med Bull 1984; 40: 380-386. HARBURG E, ERFURT JG, CHAPE C, HAUERSTEIN LS, SCHULL WJ, SCHORK MA. Sociological stress areas and black-white blood pressure: Detroit. J Chron Dis 1973; 26: 595-611. GOLDBERG EL, COMSTOCKGW, GRAVES CG. Psychosocial factors and blood pressure. Psycho1 Med 1980; 10: 243-256. COBB S, ROSE RM. Hypertension, peptic ulcer and diabetes in air traffic controllers. JAm Med Assoc

1973; 224: 489-492. 17. 18.

JONSSONA, HANSSEN L. Prolonged exposure to a stressful stimulus (noise) as a cause of raised blood pressure in man. Lancet 1977; i: 86-87.. D’ATRI DA, OSTFIELDAM. Crowding: its effects on the elevation of blood pressure in a prison setting.

Preventive Med 1975; 4: 550-566. 19. 20. 21. 22. 23. 24. 25. 26. 21. 28. 29. 30. 31.

D’ATRI DA, FITZGERALDEF, KASI SV, OSTFIELD AM. Crowding in prisons: the relationship between changes in housing mode and blood pressure. J Psychosom Med 1981; 43: 95-106. KIDSON MA. Personality and hypertension. J Psychosom Res 1973; 17: 35-42. OSTFIELD AM, LEBOVITZ BZ. Personality factors and pressor mechanisms in renal and essential hypertension. Arch Intern Med 1959; 104: 43-52. COCHRANE ER. Hostility and neuroticism among unselected essential hypertensives. J Psychosom Res 1973; 18: 215-217. HOKANSEN JE, BURGESSM, COHEN MF. Effects of displaced aggression on systolic blood pressure. J Abnorm Sot Psycho1 1963; 67: 214-218. FISHMAN CC. Need for approval and the expression of aggression under varying conditions of frustration. J Personal Sot Psycho/ 1965; 2: 809-816. FOULDS G. Personality and Personal Illness. London: Tavistock, 1965. WHEATLEY D. Psychiatric aspects of hypertension. Br J Psychiat 1975; 127: 327-336. COCHRANE ER. Neuroticism and discovery of high blood pressure. JPsychosom Res 1969; 13: 21-23. MANN AH. Psychiatric morbidity and hostility in hypertension. Psychol Med 1977; 7: 653-660. COTTINGTONEM, BUCK BM, HO&E JS, HAW~HORNEVM. Psychological factors and blood pressure in Michigan. Statewide Blood Pressure Survey. Am J Epidemiol 1985: 121: 515-529. WILLIAMSRB, KIMBALLCP, WILLIAIUJHN. Inflience of interpersonal interaction upon diastolic blood pressure. Psychosom Med 1972; 34: 194-198. HARRIS RE, SOKOLOW M, CARPENTER LG, FRIEDMAN M, HUNT SP. Response to psychological stress in persons who are potentially hypertensive. Circulation 1953; 7: 874-879.

540 32. 33. 34.

35.

ANTHONV H. MANN FRIEDMAN M, ROSENMANNRH. Association of specific overt behaviour patterns with blood pressure and cardiovascular findings. J Am Med Assoc 1959; 169: 1286-1296. JENKINS CD. Recent evidence supporting psychologic and social risk factors for coronary heart disease. New Engl J Med 1976; 294: 987-1033. ROSENMANNRH, BRAND RS, JENKINS CD, STRAUSSR, Wua~ M. Coronary heart disease in the Western collaborative group study: final follow up experience of 8I/2 years. JAm MedAssoc 1975;233: 872-877. SKEKELLERB, SCHOENBERGERJA, STAMLERJ. Correlations of JAS Type A Behaviour pattern score.

J Chron Dis 1976; 29: 381-394. 36. MANUCK SB, CRAFT R, GOLA KJ. Coronary prone behaviour and cardiovascular response. Psychophysiology 1978; 15: 403-411. 37. MARMOT MC. Type A behaviour and ischaemic heart disease. Psychol Med 1980; 10: 603-606. 38. AYMAN D, PRATT JH. Nature of symptoms associated with essential hypertension. Arch Intern Med 39. 40. 41. 42.

43. 44. 45. 46. 47. 48. 49.

1931; 47: 676-687. SA~NSBURYP. Neuroticism and hypertension in an outpatient population. J Psychosom Res 1964; 8: 235-238. ROBINSONJO. A study of neuroticism and casual arterial pressure. Br JSoc C/in Psycholl962; 2: 56-64. Leader: Symptoms in hypertension Br Med J 1976; i: 1551-1552. MONK M. Psychologic status and hypertension. Am J Epidemiol 1980; 112: 200-208. SOGHIKIAN K, FALLICK-HUNKLER E, URY HK, FISHER AA. Effect of high blood pressure treatment and awareness on emotional well being. C/in Invest Med 1981; 4: 191-196. MEDICAL RESEARCH COUNCIL. Randomised controlled trial of treatment for mild to moderate hypertension. Br Med J 1977; i: 1437-1445. MANN AH. Hypertension: psychological aspects and diagnostic impact in a clinical trial. Psychol Med supplement 5, 1984. GOLDBERG DP. The detection of psychiatric illness by questionnaire. Maudsley Monograph, No. 22. Oxford: Oxford University Press, 1972. PARSONS T. Social structure, dynamic process: the case of modern medical practice. In: The Social System. Glencoe: Free Press, 1951. NATIONAL INSTITUTE OF HEALTH. The Public and High Blood Pressure. DHEW Publication, No. 75. Bethesda, Maryland: NIH, 1973. BLUMHAGEND. Hyper-tension: a folk illness with a medical name. Culture Med Psych& 1980; 4:

197-227. 50. 51.

MUSTACCHI P. Interface of the work environment and hypertension. Med Clinics N Am 1977; 61: 531-545. HAYNES RB, SACKETT DL, TAYLOR DW, GIBSON ES, JOHNSON AL. Change in absenteeism and psychosocial function due to hypertension screening and therapy among working men. New Engi

J Med 1978; 299: 741-744. 52. MOSSEY JM. Psychosocial consequences of labelling in hypertension. Clin Investigat Med 1981; 4: 20 l-207. 53. ALDERMAN MH. Hypertension control at the work site. J Occup Med 1976; 18: 793-796. 54. 55. 56. 57. 58.

59. 60. 61. 62. 63. 64.

65. 66. 67.

ALDERMAN MH, CHARLSON ME, MELCHIER LA. Labelling and absenteeism: the Massachusetts Mutual experience. C/in Investigut Med 1981; 4: 165-171. SACKETT DL. Introduction to Symposium. Clin Investigot Med 1981; 4: 163-165. DOYLE AE, SMIRK FH. Hypotensive action of reserpine. Luncet 1954; ii, 1096. LOCKET S. Oral preparations of rauwolfia serpentina in treatment of essential hypertension. Br Med J 1955; i; 809. BANT WP. Antihypertensive drugs and depression-a reappraisal. Psycho1 Med 1978; 8: 275. PRICHARD BNC, GILLAM PMS. Treatment of hypertension with propranolol. Br Med J 1969; i: 7. BULPITT.CJ, DOLLERY CT. Side effects of hypotensive agents and evaluated by a self administered questionnaire. Br Med J 1973; iii: 485. BULPITT CJ, DOLLERY CT, HOFFBRAND H. Contribution of psychological features to the treatment of hypertensive patients. Psycho1 Med 1977; 7: 653. SHAPIRO D, SCHWARTZ GE, TURSLEY B. Control of diastolic blood pressure in man by feedback and reinforcement. Psychophysiology 1972: 9: 296-304. PATEL CH. Yoga and Biofeedback in management of hypertension. Luncet 1973; ii: 1053-1055. PATEL CH, NORTH WRS. Randomised controlled trial of yoga and feedback in the management of hypertension. Lancet 1975; ii: 93-95. JUHL A, STRANDGAARDS. Treatment of high blood pressure with relaxation and biofeedback. Scund J Clin Lab Invest 1985; 45; Supp. 1976: 70-81. MEDICAL RESEARCHCOUNCIL WORKING Pmrv. MRC trial of treatment of mild hypertension: principal results. Br Med J 1985; 291: 97-104. KANNEL WB, Soa~m P. Hypertension in Framingham. In: Epidemiology and Control of Hypertension (Edited by 0. PAUL). New York: Stratten, 1975.

The psychological 68. 69. 70.

aspects

of essential

hypertension

541

CORSELLIS JAN. Mental illness and ageing brain. Maudsley Monograph, No. 9. Oxford: Oxford University Press, 1962. WILKIE F, EISDORFER C. Intelligence and blood pressure. Science 1971; 172: 959-961. LEWIS A. Aspects of psychosomatic medicine. In: Inquiries in Psychiatry, 193-214. London: Routledge and Kegan Paul, 1967.