Chronic fatigue syndrome and occupational health

Occup. Mod. Vol. 47. No. 4, pp. 217-227, 1997Copyright C1997 Rapid Science Publishers fof SOM

Printed In Great Britain. All rights reserved0962-74aV97

Chronic fatigue syndrome andoccupational healthA. Mounstephen* and M. Sharpet

*Cramond Glebe Gardens, Edinburgh EH4 6NZ, UK; ^ University ofEdinburgh, Royal Edinburgh Hospital, Edinburgh EH 10 5HF, UK.

Chronic fatigue syndrome (CFS) is a controversial condition that many occupationalphysicians find difficult to advise on. In this article we review the nature anddefinition of CFS, the principal aetiologic hypotheses and the evidence concerningprognosis. We also outline a practical approach to patient assessment, diagnosisand management. The conclusions of this review are then applied to the disabilitydiscrimination field. The implications of the new UK occupational health legislationare also examined. Despite continuing controversy about the status, aetiology andoptimum management of CFS, we argue that much can be done to improve theoutcome for patients with this condition. The most urgent needs are for improvededucation and rehabilitation, especially in regard to employment. Occupationalphysicians are well placed to play an important and unique role in meetingthese needs.

Key words: Chronic fatigue syndrome (CFS); occupational health; rehabilitation.

Occup. Mod. Vol. 47, 217-227, 1997

Ricaved 12 Stpumber 1996; acctpud in final form 24 February 1997.

INTRODUCTION

The problem of the employee with persistent inca-pacitating idiopathic fatigue is one which mostoccupational physicians are likely to encounter. Casesof this nature tend to prompt requests from bothemployer and employee for advice on fitness for work,duration of incapacity, the need for modified workduties and, in severe and prolonged cases, eligibilityfor medical retirement.

In advising on such issues occupational physicianshave to cope with a number of problems. The existenceof a discrete disease entity [whether it be termedchronic fatigue syndrome (CFS), myalgic encephalo-myelitis (ME), or one of a number of other terms ofvarying degrees of descriptive accuracy] remains thesubject of debate. Although there are now a numberof widely agreed working case definitions for CFS,there is still no diagnostic test and no agreementregarding its pathological basis. To make matters worse,views on the optimum medical management of theCFS have been conspicuously polarized. These con-troversies have left the occupational physician in somedifficulty when advising on issues such as return to

Correspondence and reprint requests to: A. Mounstephen, 14,Cramond Glebe Gardens, Edinburgh EH4 6NZ, UK. Tel: (+44) 131247 2014; Fax: (+44) 131 247 2121.

work and on the prospects for recovery. This paperconsiders first the nature of CFS and current viewson its causation, current approaches to managementand implications for occupational heath practice.

FATIGUE AND CHRONIC FATIGUE SYNDROME

What is fatigue?

The word fatigue may refer both to a decrement inperformance and to a subjective feeling.1 In the clinicalcontext we are concerned principally with fatigue asa subjective feeling of weariness, lack of energy andexhaustion.2 As such fatigue, like pain, is a commonhuman experience.

Fatigue and work

A greater or lesser degree of fatigue has long beenrecognized as an inevitable consequence of work,especially work that demands heavy muscular effort.?With the advent of factory working the additionalimportance of other physical factors (such as ventila-tion, the thermal environment and noise) wererecognized. In 1908, Oliver noted that in the interestsof minimizing the harmful effects of fatigue 'the hoursof toil should be proportional to the nature of thework and its fatiguing character' and that 'we can at

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any rate insist that in the factory and workshop theconditions under which work is carried on shall be ashealthy as possible.'4 Perhaps reflecting the changingnature of work, more recent studies have highlightedthe importance of psychological factors in the causa-tion of fatigue at work. For example a recent reportidentified 'low job challenge, low job control, poorquality supervision, low pay rates, low information-processing demand and low physical demand'.5

Fatigue as illness

A clinical syndrome of severe fatigue accompanied byother symptoms including poor concentration, irrita-bility and muscle pain has been recognized at leastsince the last century and possibly before.6 In the lastcentury such patients were given a diagnosis ofneurasthenia. This was an illness of uncertain cause,but commonly ascribed to the effect of the stresses ofmodern life on the nervous system.7 As the yearspassed the diagnosis fell out of common usage(although it is still retained as a residual category inthe current ICD-10 classification8). Whilst it is possiblethat the actual prevalence of fatigue in the populationalso waned, it seems more likely that patients withsimilar symptoms were given alternative diagnoses.These diagnoses have been various and since psychia-trists and general physicians have practised in separatemedical systems, each has developed their own wayof conceptualizing such patients.9

Fatigue as occult disease and ME. Physicians used todiagnosing and treating physical disease have tendedto assume that severe fatigue was caused by a hiddenor occult disease. The term Myalgic Encephalomyelitis(ME) has been used in this context to define asupposedly specific disease associated with viralinfection.10 The term continues to enjoy popularusage.11 Despite this the existence of ME as a specificsyndrome remains unestablished (despite the fact thatit is listed in ICD-1012) and no specific disease processhas so far been identified.9'12 Use of the term is bestavoided.13

Fatigue as depression. Psychiatrists on the other hand,have tended to assume that patients complaining offatigue suffer from a psychological disorder, usuallydepression.14 Where depression was not obvious, it wasoften considered to be 'masked' or 'atypical'.15 Whilstthere is evidence that many patients presenting withfatigue are best described as having depressivedisorder, a significant proportion are probably not,9

and depression may be an inappropriate diagnosis forthem.

Chronic fatigue syndrome

In the light of this lack of an adequate diagnosis andunhelpful polarization of views, the term chronicfatigue syndrome (CFS) was welcomed as a descriptive

Table 1. Case definition of chronic fatigue syndrome (as definedby Fukuda et air)

Inclusion criteria:

Clinically evaluated, medically unexplained fatigue of at least6 months duration that is:

Of new onset (not life-long)

Not the result of ongoing exertion

Not substantially alleviated by rest

A substantial reduction in previous level of activities

The occurrence of four or more of the following symptoms:

Subjective memory impairment

Sore throat

Tender lymph nodes

Muscle pain

Joint pain

Headache

Unrefreshing sleep

Post-exertional malaise lasting more than 24 hours

Exclusion criteria:

Active, unresolved or suspected disease

Psychotic, melancholic or bipolar depression (but not simplemajor depression)

Psychotic disorders

Dementia

Anorexia or bulimia nervosa

Alcohol or other substance misuse

Severe obesity

syndrome label.16 Most recently the British 'Oxford'17

and American CDC16 case definitions have beensuperseded by international consensus.2 This latestdefinition is explicit in offering nothing more than aworking description of a clinical problem, pendingfurther understanding. Its diagnostic criteria are listedin Table 1.

Limitations of the current case definition of CFS. Al-though widely accepted, this new case definition stillhas major limitations. First, many patients with CFSalso meet criteria for psychiatric diagnoses. Theseinclude depressive and anxiety disorders, as well asmodern neurasthenia and somatoform disorders.9 Insome, but not all cases, this psychiatric diagnosis isan adequate description of the illness and the diagnosisof CFS may be considered superfluous.

Second, there is no evidence that the case definitionfor CFS selects a homogenous patient group.18 In factCFS is almost certainly heterogeneous on a numberof clinical variables including psychiatric diagnosis andillness beliefs.9 This problem indicates the urgent needfor a workable subclassification of the syndrome.

Is CFS a valid diagnosis? What then is the status ofCFS as a diagnosis? The current definition describesa clinical presentation and not a specific disease.Whether the aetiology, course and treatment implica-tions support its differentiation from psychiatric

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syndromes in the long term remains to be seen. Atpresent a sensible approach is to qualify a diagnosisof CFS by any coexisting psychiatric syndromes.According to such a scheme CFS would be sub-classified into CFS/depression, CFS/anxiety and CFSwithout depression or anxiety disorder. This last cate-gory is equivalent to ICD-10 neurasthenia.8

Is CFS a useful diagnosis? The choice of diagnosis fora patient with medically unexplained fatigue shouldbe pragmatic. There is little point in making a diagnosisof CFS if the patient's symptoms are clearly those ofdepression or anxiety. On the other hand if fatigue isthe most prominent symptom, a diagnosis of CFS maybe appropriate. A diagnosis that the patient findsacceptable has the benefit of offering a coherent labelfor their symptoms and will reducing the risk that theywill embark on a fruitless search for a 'better' expla-nation.19 The label of CFS also avoids the misleadingconnotations of 'pseudo-disease' diagnoses such aschronic Epstein-Barr virus infection or ME.

In summary, a diagnosis of CFS may be clinicallyuseful if four important caveats are observed. First,CFS should be explicitly regarded as a presenting clini-cal syndrome, rather than a specific disease process.Whilst this is not to deny the possibility that there arespecific pathophysiologic processes underlying thesyndrome, a balance must be struck between accep-tance of this possibility, and unjustified enthusiasm forunproven aetiologic theories. Second psychiatric syn-dromes that have clinical utility such as majordepressive disorder should be sought and if present,should be included in the diagnostic statement as de-scribed above. Third, whilst the current case definitionof CFS specifies only symptoms, patients' beliefs andbehaviour are often a prominent and important partof the clinical presentation20 and also need to be in-cluded in any useful summary of the case. Finallyrather than becoming side-tracked on the question ofwhether CFS is really 'medical' or really 'psychiatric'in nature, management is likely to be more effectiveif both the physician and the patient adopt an open-minded and pragmatic approach to this often frustratingclinical problem.

Who gets CFS?

Most of the research into the course of chronic fatiguesyndrome is based on hospital referred populations

and as such may not be an accurate reflection of whathappens in the general population or even in generalpractice.21 There is however some evidence that thecondition is most commonly, but not exclusively,diagnosed in young and middle-aged females. Amongsthospital referrals professional occupations are overrepresented.22 Clinical observations also suggest thatit is conscientious perfectionistic individuals who maybe more vulnerable to becoming stressed by high levelsof work demand who are more Likely to present withchronic fatigue.23*24

What is the cause of CFS?

Current evidence suggests that the consideration ofmultiple causal factors is necessary to explain CFS.These may be conveniently classified as biological,psychological and social. Aetiology may be furtherclarified if these factors are divided into predisposing,precipitating and perpetuating factors (see Table 2).

Biological factors. Clinical observations of patients withCFS have led to the investigation of a number ofhypotheses about the underlying pathophysiologicmechanism. Perhaps because patients commonlydescribe their illness as beginning with 'flu-likesymptoms', many investigators have sought objectiveevidence of initiating viral infection. Whilst a prospec-tive follow-up of people with acute Epstein-Barr virusinfection found that some patients went on to developchronic fatigue,25 a large prospective study in primarycare found no association between self-reported viralinfections and subsequent chronic fatigue.26

Chronic ongoing virus infection has been a populartheory to explain the persistence of the symptoms ofCFS, and Epstein-Barr virus has been one of the mostlikely suspects.27 Although there may be an associationbetween positive EBV serology and CFS, the role ofchronic infection in perpetuating CFS is doubtful.28

Other infectious agents which have been investigated,but not conclusively shown to be associated with CFS,include the enteroviruses and the retroviruses.29

Although the evidence for an association betweenimmunologic abnormalities and CFS is more consis-tent than that for infective agents,30 the specificity andcausal importance remains unclear.31

Complaints about sleep are almost ubiquitous inpeople suffering from CFS. While some studies haveidentified major sleep disorders such as sleep apnoea

Table 2. A hypothetical causal model of CFS

Predisposing Precipitating Perpetuating

Biological

Psychological

Social

Genetic

Previous depression

Personality

Stigma

virus

Response to stress

Stresses

Neuroendocrine disturbance

Inactivity

Disease attribution

Avoidant coping style

Life conflicts

latrogenic factors

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and narcolepsy in a minority of patients,32 idiopathicinsomnia is much more common.33 This poor qualitysleep may contribute to the daytime fatigue but is aninadequate explanation for the illness.

Abnormalities in the cardio-respiratory systems thatmay underpin exercise intolerance have been reportedby several investigators. These include hyperventila-tion,34 abnormal cardiac function35 and posturalhypotension.36 At present the frequency and impor-tance of these observations is uncertain. Importantlycurrent evidence suggests that exercise is not harmfulfor people with CFS.37

Recent studies of nervous system and endocrinefunction in CFS may hold more promise. Findingsinclude low levels of cortisol, and an abnormal adrenalresponse to stress and exertion;38 abnormal functioningof cerebral serotonergic systems39 and subtle abnor-malities in brain perfusion.40 However, none of thesefindings are unique to CFS and all require confirma-tion.

Psychological factors. Although there is a strong asso-ciation with depression, both current and previous,depression alone is probably an inadequate explanationof the illness in many cases.41 A process referred toas 'somatization' is commonly invoked to explain whypatients present with medically unexplained com-plaints such as fatigue.42 It implies that the symptomsof CFS are caused by emotional distress beingexpressed somatically rather than psychologically.Whilst emotional disturbance is a parsimonious alter-native to some of the more elaborate pathophysiologicmechanisms proposed for CFS it must be rememberedthat somatization is a hypothetical process; its presenceis difficult to prove and there is no 'test' for it.

Other psychological factors proposed includeinaccurate beliefs about the illness and unhelpfulcoping behaviour. Systematic studies have confirmedthat patients attending specialist clinics with CFStypically attribute their symptom to organic diseaseand strongly resist psychological and psychiatricexplanations;43 views contrary to the current evidence.Related to these illness beliefs is a tendency to copewith the illness by avoiding any activity that exacer-bates symptoms.44'45 Avoidance is associated withpersistent disability and may be the link betweenobserved association of physical disease attributionand poor outcome.46

Social factors. Social factors appear to play a role inCFS. There is some evidence for an excess of lifestresses as well as self-reported infection prior to theonset of CFS47 although the precise role of stress inthe aetiology of the syndrome remains uncertain.Patients with CFS may be reluctant to present withemotional complaints because they are more suscep-tible to the social stigma attached to 'psychiatric'explanation for their distress.46148 Another potentiallyimportant social factor is the availability of misleadinginformation about the illness. Both self-help books and

the media have tended to emphasize 'medical' expla-nations for the symptoms of CFS at the expense ofmore psychiatric or psychological conceptualizations.49

Physicians may also unwittingly contribute to thisprocess.50

It has also been suggested that CFS may serve aculturally defined function of social communication,which allows a socially acceptable and hence 'non-psychiatric' expression of distress and protest aboutintolerable occupational and personal pressures.51

Summary. In summary there is tantalizing evidencefor the operation of a variety of biological factors inCFS but none have yet been shown to be specific.Psychological factors clearly have importance in atleast some patients, but alone do not offer a fullexplanation of the illness. Social influences, especiallyiatrogenic and occupational influences may have beenunderestimated. Given this range of aetiologic factors,an integrated 'biopsychosocial' approach is the bestway forward. For the purpose of planning treatment,illness perpetuating factors are more important thenpredisposing or precipitating factors.

What is the prognosis?

In primary care, fatigue is a common complaint witha relatively good outcome.52 However patients attend-ing hospital with chronic fatigue who are not giveneffective treatment (see below) have a much worseprognosis.53 This is especially true for those with aconviction that the cause of the illness is 'purely physi-cal'.20-54 Clinical experience also suggests that poorsocial and occupational functioning before the onset ofillness predicts poor outcome and that, as with backpain, pre-illness dissatisfaction with employment mayreduce the likelihood of a future return to work.55

THE MANAGEMENT OF CFS

How should patients be assessed?

Treatment must be preceded by assessment.56 Acombined medical and psychiatric assessment isrecommended in every case2 and is summarized inTable 3.

Table 3. Assessment of a patient with chronic fatigue

Exclude organic diseaseCareful history and examinationSpecial investigations only if indicatedKeep open mind

Assess for psychiatric disorderSystematic enquiryBeware smiling facade

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Excluding organic disease

A few of those patients who present with severe chronicfatigue will be found to have occult organic disease.57

The frequency with which organic disease is foundwill depend on how thorough an assessment the patienthas already received. Even if disease is not evident atassessment, it is wise to remain vigilantly aware of thispossibility and to reinvestigate if new clinical signsappear. The conditions to be considered includehypothyroidism, anaemia, Addison's disease andobstructive sleep apnoea.58

In most cases of chronic fatigue few laboratoryinvestigations are necessary; if a careful history andphysical examination do not point to alternativediagnoses, additional laboratory screening tests willadd little.13'59

Identifying psychiatric syndromes. All patients shouldhave a psychiatric history taken and their mental stateexamined. The assessment should seek evidence ofmajor depression, anxiety and panic disorder, and alsoevaluate any suicidal intent as these all have implica-tions for treatment. The psychiatric assessment shouldbe systematic as hidden distress is common and casualestimates of the patient's degree of distress may bemisleading.60

Obstacles to recovery. An adequate individual patientassessment must identify all the important obstaclesto recovery. It is necessary therefore not to stop atdiagnosis but also to include a systematic individual-ized description of each case. Important aspects to beincluded are the individual's beliefs about their illness,their coping behaviour, emotional state, physiologicalcondition, interpersonal and occupational problemsand the family's understanding of the illness. Thesefactors may be listed as a formulation of the case (seeTable 4).

Diagnosis and formulation. If appropriate, the diagnosismay be given as CFS together with coexisting psychiatricdiagnoses as described above. Relevant illness perpetu-ating factors should also be listed as in Table 4.

Are there any effective treatments?

The management of patients with CFS should be based

Table 4. Elements of a biopsychosocial assessment

Biological Physical de-conditioning

Other processes (?)

Psychological Beliefs

Coping behaviour

Mood

Social Stressors (including occupational)

Family beliefs

latrogenlc

Table 5. Management of CFS

General

Pharmacological

Non-pharmacological

Accept illness

Educate about multifactorial nature

Encourage self-help and normal activity

Consider antidepressant drugs

Avoid poly pharmacy

Experimental drugs only in trials

Gradual increase in exercise

Cognitive behaviour therapy

Problem solving of occupational andother difficulties

on both diagnosis and an individualized formulationof the problem. Treatment can be divided into generaland specific strategies. The latter include pharma-cological therapies, exercise therapy, psychotherapyand social interventions (see Table 5).

General strategies. Several basic steps are useful in theinitial care of patients with CFS. The first is toacknowledge the reality of patients' symptoms and thedistress and disability associated with them. Thesecond is to provide appropriate education about thenature of the syndrome to both the patient and theirfamily, whilst avoiding unproductive argument. Thethird is to gently encourage a return to normal func-tioning by overcoming avoidance and regaining thecapacity for physical activity. This general approach is aprerequisite to any more specialized form of treatment.

Pharmacological treatments. Many pharmacologicaltreatments have been suggested for patients with CFS.To date, none have been shown to be of proven efficacyand several are potentially harmful.61 Despite this lackof evidence patients who are clearly depressed shouldbe offered treatment with antidepressant drugs. Thereis some evidence to support the use of these drugseven in the absence of definite depressive disorder,62

although a recent randomized trial of fluoxetine invery chronic cases failed to demonstrate any benefitover placebo.63 Of available agents none is clearlysuperior for this patient group. Clinical experiencesuggests that the SSRI anu'depressants may be bettertolerated and the clinical similarities of CFS to 'atypi-cal' depression may suggest a role for monoamineoxidase inhibitors.64 Patients are often reluctant to takeantidepressants and careful explanation and follow-upare required. Other pharmacological agents shouldonly be used with care and preferably only as part ofrandomized controlled trials.65

Exercise therapy. This should be considered for patientswho are physically inactive. In both fibromyalgia andCFS a modest amount of evidence suggests that gradedincreases in physical activity are helpful in improvingfunction and relieving symptoms.66'67 The simplisticapplication of exercise regimens, particularly if givenwithout explanation and follow-up, is unlikely to be

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helpful however, and may damage the patient'sconfidence.

Psychotherapy. Psychosocial difficulties may be tar-geted using psychotherapy. Patients may be reluctantto consider the role of psychological factors makingthe application of psychotherapy potentially difficult,but not impossible. Whilst brief psychotherapeuticapproaches may have a place in the management ofselected patients the only psychological treatment sup-ported by evidence is cognitive behavioural therapy.This form of treatment is especially well-fitted to thetask of helping patients to achieve a more helpful viewof the illness, and to adopt more effective copingstrategies.68

The efficacy of several forms of cognitive behaviourtherapy in CFS has been evaluated. Encouragingresults from an initial study of an active rehabilitativetype of cognitive behaviour therapy69 were not repli-cated in a subsequent randomized trial of a brieferform of this therapy.70 However two recent randomizedtrials of intensive rehabilitative cognitive behaviourtherapy especially designed for patients with CFS havedemonstrated its effectiveness compared with conser-vative medical care71 and with relaxation therapy.72

This form of cognitive behaviour therapy placedparticular emphasis on helping patients to reappraisetheir illness beliefs, as well as on increasing activityand solving social problems, and consisted of 10-20weekly individual treatment sessions. While the resultsof further similar studies are awaited we may concludethat cognitive behaviour therapy offers a potentiallyuseful approach to the rehabilitation of many patientswith CFS.

Social interventions. There is also some evidence thata gradual approach to work rehabilitation can beeffective73 — an approach considered further later inthis review.

Summary. Whilst a variety of treatments includingantidepressant drugs and activity programmes may behelpful, rehabilitative cognitive behavioural therapyenjoys the best empirical support.

IMPLICATIONS FOR OCCUPATIONALHEALTH PRACTICE

The size of the problem

Recent population studies have confirmed that fatigueis a common symptom.26'74'75 In a questionnaire-basedcommunity survey in southern Scotland 'substantialfatigue' (sufficient to be considered a major problemby the subject) was reported by 38% of the respon-dents.75 A larger questionnaire-based study in southernEngland also found that 38% of respondents had 'sub-stantial fatigue'.74 CFS is less common, the preciseestimate varying according to the population studied

and the case definitions used.76 However the Scottishstudy mentioned above found 'substantial fatigue' ofat least six months duration in 14% of respondents,although in the authors' view only 0.56% of respon-dents fully satisfied the Oxford criteria.75 In thesouthern England study 18.3% of respondentsreported 'substantial' fatigue lasting six months orlonger but only 1% met criteria for CFS.74 From theseand other studies the overall population prevalence ofCFS has been estimated as approximately 2% of thepopulation13 although only a minority of these regardthemselves as having CFS.77

Several studies suggest that CFS is probably no moreor less common among people in employment thanamong the population as a whole and that it may occurin any occupational group.75'78'79 Although specific studiesof the prevalence of CFS in occupational groups arelacking, extrapolation of the results of recent generalpopulation studies described above suggest that mostoccupational physicians working for large organiza-tions will encounter the problem. A small scale surveyundertaken by one of the authors confirmed that allof the full-time occupational physicians questionedwere indeed accustomed to giving advice on cases ofCFS in the course of their practice.

Reasons for involvement of the occupationalphysician

When an employee's work is affected by chronicfatigue, occupational physicians inevitably becomeinvolved in advising on issues such as recruitment,fitness for work, sickness absence, rehabilitation andmedical retirement. These are listed in Table 6.

Whilst the occupational physician may not normallybe the prime mover in co-ordinating therapy, it isarguable that he or she may be able to make a keycontribution to the therapeutic process. It must beacknowledged however that the perceived need to 'sitin judgement' upon such cases can limit the prospectsfor a fruitful therapeutic relationship with the sufferer.

Recruitment

The recruitment process may require that the occu-pational physician must reconcile an apparent conflictbetween the interests of employers and pension fundson the one hand and those of job applicants with ahistory of CFS on the other. Recruitment processesvary widely but commonly include an assessment ofthe applicant's fitness for the employment proposed.This is often based on a screening questionnaire. In

Table 6. Issues for the occupational physician

Recruitment

Membership of pension schemes

Referral of existing employees

Occupational rehabilitation

Termination of employment

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many cases only those applicants whose questionnairesgive some indication of significant past or presenthealth problems are subject to further assessment. Itis likely that those individuals with recent or currentchronic fatigue will be reluctant to admit to a diagnosisof CFS, not least because of its reputation for causingprotracted incapacity. In cases where the medical detailsprovided attract further scrutiny by the occupationalhealth department, routine physical examination isunlikely to elicit significant abnormality, even in casesof current CFS. On the other hand a more probinghistory and a brief and straightforward assessment ofthe mental state may be informative in revealingevidence of depression, anxiety and illness beliefs.

For applicants who appear to have made a full andsustained recovery from CFS, there is unlikely to beany valid reason for advising against employment onmedical grounds. For more recently recovered appli-cants and for those in whom the recovery process isapparently not yet complete, more caution is necessary.In particular care should be taken to match theproposed duties in employment to the subject'scapabilities. Strenuous physical work, long workinghours, rapidly changing shift patterns, work requiringsustained high levels of attention and concentrationand work likely to place sustained high pressure onthe employee are inadvisable or at least require carefulmonitoring until it is clear that recovery is completeand sustained.

A further concern arises where there is the possibilityof exposure to agents in the working environmentwhich may themselves give rise to symptoms whichmay resemble those of CFS because of the potentialfor confusion concerning the cause of any exacerbationof symptoms. For this reason work which may involvepotential significant exposure to substances such asheavy metals or solvents is probably inadvisable forthose with persisting CFS symptoms.

Pension schemes

Occupational physicians are frequently required toadvise on fitness for pension scheme membership. Itis usually accepted that applicants who are fit for thejob are fit for pension scheme membership, althoughthis is ultimately a matter of individual pension schemepolicy. Pension schemes are inevitably particularlyconcerned with the life expectancy of prospectivemembers and there is no evidence that a history ofCFS past or present has an adverse effect on this(except in as much as some individuals with the labelof CFS may in fact be suffering from depression withits attendant risk of suicide).

Referrals of existing employees to occupationalphysicians

Whatever the circumstances of referral it is essentialthat a thorough and objective assessment of the indi-vidual be conducted as described above. Preconceived

ideas the physician may hold regarding psychologicalvs. physical causation are generally unhelpful in thiscontext, particularly if sufferers obtain the impressionthat a particular set of beliefs regarding CFS are beingdogmatically applied to them. Engaging the employeein an open discussion of the problem is essential ifany opportunities for education and rehabilitation areto be established. Protracted and sterile argumentregarding the nature and cause of the condition is lessimportant than obtaining agreement that there is aproblem and that there may be opportunities to helpthe person to overcome it.

Assessment and diagnosis. The caveats to be attachedto a diagnosis have been described above. It isparticularly important to appreciate that untreateddepressive illness may be present in a substantialproportion of cases labelled as CFS.80 Opportunitiesto identify such cases and to promote the initiation ofeffective treatment should not be lost. This may wellrequire (with the employee's knowledge and consent)dialogue between the occupational physician and theemployee's GP or specialist. It is our experience thatdelay in diagnosis resulting in long periods off workand referral to multiple 'specialists' should be avoidedas they can entrench illness behaviour and make returnto work less likely.

Obstacles to recovery and work issues. Since the role ofthe occupational physician is inevitably to advise onquestions relating to work in CFS it is important totry to arrive at a full understanding of the employee'sattitudes and beliefs in relation to their present job.Difficulties at work may have existed prior to the onsetof symptoms and may themselves represent a signifi-cant obstacle to remaining at, or returning to work.The employee may well require help to develop prob-lem solving strategies to help them deal with suchproblems. Discussion with an employee's manager andor colleagues may provide additional insight into thisaspect of the problem, as well as providing opportu-nities to ensure that any such difficulties are addressed.Whether or not specific work-related problems appearto have been present at the outset of CFS, the employeemay be anxious about the advisability of remaining ator returning to work, in the presence of continuingsymptoms. Specific concerns are likely to include afear of failure to perform to an acceptable standardand a fear that work may have an adverse affect onsymptoms and the prospects of eventual recovery. 'ME'self-help groups and literature may reinforce the latterconcern. Progress in addressing these concerns is morelikely to be achieved if an employee's beliefs and fearsare carefully explored, understood and addressed.

Occupational rehabilitation. The suggestion that a care-fully planned and supervised programme of workplacerehabilitation may be helpful needs careful introduc-tion and explanation to all concerned. Clearly thesufferer's beliefs and wishes will have a powerful effect

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upon acceptance of any such programme: an employeewho is seeking medical retirement as the only accept-able resolution of their employment situation is unlikelyto be receptive to this approach.

If workplace rehabilitation is to be attempted it isimportant that it is co-ordinated with other treatmentand rehabilitation measures. If for instance aprogramme of cognitive behavioural therapy is to beundertaken there may be opportunities to ensure thatany process of rehabilitation at work is integrated withthe therapy programme. Here again dialogue betweenthe occupational physician, employee and othersinvolved in treatment will be of great importance.Workplace rehabilitation programmes also make sub-stantial demands upon the employer, and morespecifically the line management of the employee con-cerned. The occupational physician is of course uniquelywell placed to approach the key players to discussproposals for attempts at rehabilitation. Here again aprocess of education to address inaccurate and un-helpful attitudes and beliefs may be a necessarypreliminary step. Work rehabilitation will usually needto start with a workload and hours of work that aredramatically less than normal. These are then graduallyand progressively increased depending on progress.

Although work rehabilitation sounds an arduous anduncertain venture it can be argued that a short termexpenditure of effort by all concerned is preferable toa period of outright sickness absence which is likelyto be of indeterminate and possibly protracted length.That said, considerable powers of tact and persuasionon the part of the occupational physician may berequired if a sceptical employee and manager are bothto be motivated to attempt this approach.

Can it work? The available evidence suggests thatoccupational rehabilitation of CFS sufferers can bemore than just a theoretical possibility. Peel reportedon the cases of 13 airline employees suffering from'post viral syndrome' (specific case identification cri-teria were not clearly stated).73 Seven of the thirteenwere able to resume normal duties within 8-28 weeksfrom initial onset. The work rehabilitation process wasreportedly very slow (although the pace was reportedlyat the discretion of the sufferer without the setting ofagreed activity targets as used in cognitive behaviouraltherapy). 'Excessive' activities outside work were dis-couraged during the rehabilitation period. Efforts weremade to ensure that at the outset work undertakenwas of a quiet 'backroom' nature with avoidance ofmeetings and demanding 'open ended' tasks. Substan-tial line management co-operation was enlisted withcareful briefing on required restrictions and likely timecourse.

It is notable that the median period of sicknessabsence in these cases was 8 weeks (including furtherabsences necessary after commencing rehabilitation).This is relatively short and although influenced byeach individual's job, personality and home circum-stances, indicates that an active approach aimed at

early rehabilitation of committed and highly motivatedemployees can achieve worthwhile results.

Our small survey suggested that a similar approachhad been adopted by many occupational physicians ina variety of work settings. All indicated that they soughtto promote rehabilitation of employees with CFS byadvising wherever possible on an early return to work,with duties and hours restricted to suit the needs ofthe individual. They also reported using periodicreviews and counselling from occupational health staff.Most stressed the importance of enlisting managementunderstanding and support and of emphasizing to allconcerned the likelihood that progress would be slowand faltering. Although the majority reported thatmanagement were usually supportive of such efforts,several noted that the employees themselves could beresistant and apparently poorly motivated. This wasparticularly the case where absence was alreadyprolonged and illness behaviour firmly established. Notsurprisingly all found the success of such an approachto be variable (and worse where symptoms have beenpresent for a year or more), but most felt that theeffort was usually worthwhile.

Termination of employment

In cases where incapacity is prolonged, efforts atrehabilitation are resisted or unsuccessful and prog-nosis appears to be poor, the possibility of loss ofemployment inevitably arises. Legally, termination ofemployment may be held to be fair and reasonablewhere an employer has established on the basis ofsound medical evidence that an employee is unable toperform his or her contractual duties because of illhealth such as chronic fatigue. In such cases theemployer's ability and willingness to offer suitablealternative duties may also be considered in an Indus-trial Tribunal. The Disability Discrimination Act81 mayhave significant implications for this and other aspectsof the employment of CFS sufferers (see below).

Medical retirement. The occupational physician mayalso be asked to advise on the possibility of retirementon the grounds of ill health if an employee with CFSis covered by a company pension scheme which makesthis provision. Qualifying criteria inevitably vary,although permanent inability to undertake normal dutiesfor reasons of ill health is a common stipulation. Giventhe relatively uncertain prognosis of CFS, it wouldseem unlikely that this criterion would be satisfiedunless incapacity is severe and long-established withpoor prognostic indicators. It certainly seems un-reasonable to conclude that incapacity is permanentwithout an adequate trial of treatment and rehabilita-tion having been undertaken. The permanence ofincapacity in the context of eligibility for medicalretirement is a highly contentious issue and a numberof pension schemes have received high profile chal-lenges to decisions not to award medical retirementpensions to employees with CFS.82

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A. Mounstephen and M. Shape. Chronic fatigue syndrome and occupational health 225

Eligibility for benefits. In discussing the question ofmedical retirement with CFS sufferers the occupa-tional physician should be aware of the Departmentof Social Security's current view on sufferers' entitle-ment to Incapacity and Disability benefits. Incapacitybenefit will be paid on the basis of the certifyingdoctor's diagnosis until the All Work Test is applied.Where the diagnosis is one of CFS the test is likelyto be applied to a claimant in employment on expiryof their entitlement to Statutory Sick Pay (usually at28 weeks). The All Work Test is concerned more withfunctional capacity than with the precise diagnosis. Ittakes into account symptoms such as pain, stiffnessand fatigue and also problems associated with psychi-atric illness. An adjudicating officer's decision to awardbenefit would normally be followed by a case reviewin at least six months. Those who fail the All Work Testwould normally be referred to the Employment Servicewith a view to a planned programme of rehabilitationor training (P. Sawney, personal communication).

Disability benefits include the Disability LivingAllowance (DLA), for which a 'self-assessment' of careand mobility needs is considered by an AdjudicationOfficer along with any additional medical information(such as an examination) which the Officer requests.Only a person with CFS who met the criteria forhigher rate DLA would be considered exempt fromthe All Work Test. The advice of the DLA AdvisoryBoard is that the case for CFS being a physical diseaseis unproven. The DSS's Disability Handbook furtheradvises adjudication officers that in CFS there isunlikely to be a need for assistance with attending tobodily functions or with mobility unless inactivity andimmobility have been so severe and protracted thatmuscle atrophy has occurred. Unless specific care and/or mobility needs are accepted, DLA is unlikely to beawarded. This issue is, unsurprisingly a matter ofdebate between the DSS and CFS/ME patient groups.

Severe Disablement Allowance (the non-contributoryincapacity benefit) may be payable to those withinsufficient National Insurance contributions to qualifyfor Incapacity Benefit. Successful applicants mustsatisfy the All Work Test and be assessed as at least80% disabled by an Adjudicating Medical Authority.At present less than one per cent of successful claimsfor Severe Disablement Allowance have a diagnosis ofCFS or ME.

CFS AND THE DISABILITY DISCRIMINATIONACT

The provisions of the Disability Discrimination Actrelating to employment became effective late in 1996and are likely to have significant implications for bothemployees and prospective employers of people withCFS. The act's definition of disability (a physical ormental impairment which has a substantial and longterm adverse effect on a person's ability to carry outnormal day-to-day activities) begs many questions, but

seems likely to be applicable to at least some peoplewith CFS. The act prohibits discrimination againstdisabled people in the recruitment and retention ofemployees and in the dismissal process. It requiresemployers to make 'reasonable' changes to their prem-ises or employment arrangements if these substantiallydisadvantage a disabled employee or prospectiveemployee, compared to a non-disabled person. Lessfavourable treatment of a disabled person can only bejustified if such treatment is relevant to the circum-stances of the case and for 'substantial' reasons.

Guidance published to date indicates that the 'rea-sonable' adjustments an employer may have to considercan be numerous and extensive, including:

• allocating some duties to another employee

• altering working hours

• transferring the employee to another place of work

• allowing absences during working hours forrehabilitation, assessment or treatment

There are also implications for occupational pensionscheme membership: an employer may not exclude adisabled person from a pension scheme withoutjustification and the disability itself is not sufficientreason.81

In practical terms these requirements may lend weightto the efforts of occupational physicians seeking topromote the rehabilitation and retention of employeeswith CFS. However the question of what is 'reasonable'behaviour on the part of employers faced with requestsfor substantial adjustments to the working arrange-ments of employees with CFS remains to be tested.A Code of Practice providing further practical guid-ance has now been published.83 It will be unfortunateif the Act leads to an undue focus on long termdisability at the expense of efforts directed at rehabili-tation and recovery.

A PLAN FOR ACTION

The occupational physician inevitably has a role toplay in advising the current or prospective employerof people with CFS. In addition he or she will haveopportunities to promote occupational rehabilitation•aimed at preventing the downward spiral often asso-ciated with loss of employment. An awareness of thetherapeutic approaches available and the evidence fortheir effectiveness is an essential prerequisite for thistask. Success depends particularly on a willingness tobecome part of a proactive approach that seeks tointervene before chronicity is established or iatrogenicharm has ensued. This proactive approach requiresthat the occupational physician is able to engage theemployee in rehabilitation, win the co-operation of theemployer and ensure the active involvement of bothGP and appropriate specialists. Above all the task isto co-ordinate and motivate all the parties involved.

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226 Occup. Med. Vol. 47, 1997

CONCLUSIONS

CFS is by no means a new illness but the terminologyand aetiologic hypotheses applied to it are likely toremain the subject of vigorous debate. Despite thisconfusion there is increasing evidence that effectiveinterventions are possible, even in the absence of acomplete understanding of the pathophysiologicmechanisms involved. The challenge to occupationalphysicians is to ensure that the need for suchinterventions is recognized at a time when they canachieve the greatest benefit for both sick employeeand employer.

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