Time, & biopsychosocial theory

This page explores the biopsychosocial theory of illness from the perspective of time. This exploration leads to specific conclusions about both the process of rehabilitation for an individual patient, and about the design and provision of rehabilitation services. It also helps in understanding problems within existing healthcare service.

The relevance of time in the process of healthcare and in the design of services receives little attention. It is only in the hyper-acute services, such as response to trauma and acute ischaemic events, that time does receive attention. The rate of change over time in different systems in the theory and in different healthcare systems may help in analysing problems with current services. It particularly may help in designing effective rehabilitation services.

This page will analyse how the seven basic systems set out in the biopsychosocial theory of illness are influenced by time. The remaining system, the temporal context, is obviously excluded.

My first hypothesis is that the rate of change varies between the seven different systems. In the first part I will consider each system and how the differences in rate of change are manifested. The evidence provided will, I hope, convince you that the hypothesis is reasonable. In essence I show that as one moves from disease to social participation, the time scales over which change occurs grow longer, logarithmically. My second hypothesis is that healthcare services need to be designed to match the rate of change seen in different aspects of illness. At present they are not

Most of this page concerns hospitals concerned with acute medical and surgical matters. However there are sections on mental health and palliative care services. The page ends considering how this analysis might inform the design and provision of rehabilitation service.

Pathology – disease

At the level of pathology, processes and changes occur in short time frames, from almost instant (seconds, such as a sub-arachnoid haemorrhage or myocardial infarction) to, usually, a few days (e.g. control of a bacterial infection). Most diagnoses are made within a few minutes or hours, either by the patient and family, or by the first doctor to see the patient. Final confirmation and achieving more detail may take longer.

The rapid rate of process and change seen in this system (organs within the body) is reflected in healthcare systems. We have emergency ambulances with paramedics able to undertake emergency care including treatments. There are acute hospital admission processes, intensive care units with 24 hour monitoring etc., set up to respond to the rapid changes.

At a hospital system level, hospital beds are monitored 2-3 times a day, discharges are (unfortunately) often arranged at short notice, and only a minority of patients remain in an acute hospital for more than seven days for direct medical care.

Many patients need ongoing disease-specific treatment for chronic diseases that cannot be cured (reversed or eliminated) but can be controlled with greater or lesser success. These patients rarely need admission to hospital for this. Although many are managed well by the general practitioner, there is an increase in disease-modifying treatments that require close expert management. Services for this are not yet well-designed.

This emphasis within hospitals on disease-centred short timeframes is illustrated by the label of “delayed discharges“. A person is deemed to be a delayed discharge when disease-centred processes are complete. This categorisation occurs, whatever need remains for other interventions such as rehabilitation, or for care to maintain safety and well-being.


At the level of impaired bodily structure or function, the patient’s experience of unusual (abnormal) bodily functioning, the time scale is generally slower, measured in hours, days or weeks. After any significant disease episode, it takes time for impairments to recover – a period of convalescence while symptoms such as muscle weakness, general fatigue, cognitive slowing etc return towards normal.

The processes underlying bodily recovery and change are slower that those underlying recovery and change within individual organ tissues. The former are physiological and cross all bodily systems which need to adapt. The latter are cellular and biochemical and are within a single system and are generally faster.

Even at organ level, some healing processes take time, such as of fractures or skin damage, or after infarction of brain. The adaptation within the body to irreversible damage usually takes longer. This will have an impact upon recovery of activities, although sometimes this impact can be reduced. For example, an external fixator can reduce the effect of a tibial fracture upon walking.

Actions to reduce impairments also take time to have an effect. Drugs for many neurological impairments such as Parkinsonian symptoms, spasticity, and neuropathic pain may take several weeks to act and often need to be titrated to an effective dose. Treatments to increase muscle strength, to reduce lymphedema, or to extend contracted joints will all take weeks.

Symptoms, signs and body function are also often the main measure by which patients and their doctors judge recovery. Sometimes the expected rate of recovery from impairment differs from the actual rate. This may cause someone to think that they have some other problem, if their expectation is for a faster than possible return to previous function. Alternatively, they may interpret continuing impairment as requiring further rest and restriction, which may then slow down improvement.

These timescales are inconsistent with hospital systems focused on disease. The timescales are also difficult to fit in with (UK) booked out-patient clinics which are often booked months ahead. Yet, without appropriate monitoring, the patient’s well-being may be compromised because incorrect expectations may influence illness, or incorrectly adjusted treatments may lead to problems.


At the level of activities and disability, the rate of change is much slower. In in presence of continuing impairment, a person needs to learn new ‘behaviours’, new ways of doing activities. All learning requires time, and learning a complex skill (or relearning it) takes much longer. Consider how long it takes an infant to learn to walk or talk. Or how long it takes to learn to cook well, or operate a complicated machine such as a car. The time scale is measured in weeks to many months, occasionally longer.

Change in performance of activities is influenced by three processes. The first is the natural change associated with ageing. In children this is a very important factor, perhaps up to the age of 20-25 years. In the older population, with no well-demarcated starting age, there is a decline in resilience and in some other phenomena such as endurance. However this phase can only be recognised after it has started. These facts influence rehabilitation, but are not themselves alterable.

The second is a natural reduction in impairment as recovery after acute tissue damage occurs. As basic skills recover, so activities become possible or easier. Much rehabilitation in the phase immediately after an acute-onset disability is based on the natural recovery process. It focuses on preventing complications, and ensuring recovered skills are recognised and used. Recovery may last many weeks.

The third is re-learning (or learning if not previously known) how to perform an activity in the present of whatever skills are preserved and are missing. This is the bulk of rehabilitation late after an acute onset disability, and in any congenital or progressive disabling disease. This process may take many months.

The much slower change at the level of activities contributes greatly to the, phenomenon of ‘delayed discharge’. The disease is cured, but it takes much longer for the disability to reduce, and for the person to adapt. Unfortunately, most hospitals at present consider that their main, if not only purpose is the diagnosis and specific treatment of disease. They do not consider rehabilitation to be within their remit, however much the person might benefit from rehabilitation.

Social participation

At the level of social participation, it takes much longer for matters to change. Friendships may take months to form, social networks evolve over years, as anyone who moves to a new town knows. Only in certain circumstances, such as institutions (e.g. a school, university or some work-places) do social networks grow more quickly.

This slow rate of change poses a challenge for rehabilitation. The lack of social contact – loneliness – is a major problem, but it will arise after almost all services have withdrawn, even rehabilitation services.


For someone who has been changed by illness such that previous social networks are lessened, change in social participation is influenced to a great extent by social context. Changes in social context are also slow. It takes years to alter social attitudes, for example to smoking or discrimination. Culture within the person’s previous networks may not change, and if it does, it will usually be slow. Meeting new people, developing relationships and entering new networks takes years.

Changes in physical context are also often slow for an individual patient. Even the provision of a wheelchair can take an inordinate time, primarily because of bureaucracy (social context). Adaptations to buildings inevitably take time. Acceptance of changes in physical context by the patient may also be slow (their personal context). For example, some people are very reluctant to use a wheelchair, or hearing aids, or a walking stick.

Last, personal context also changes very slowly, if at all. A proportion of ‘personal context’ is really simply part of the person, just as the shape of their face or the length of their arms are how that person is. It is their ‘personality’, although even this may alter slowly over time or in response to very big events. For example, a near-death experience may transform someone’s approach to life. More mundanely, personal context can be altered deliberately, for example through cognitive-behavioural therapy or education, but these take time.

In summary, most changes in context are also slow, sometimes times in decades. The main exception is in simple alterations to physical context that also do not involve any bureaucracy or significant funding.

Mental health

It will have been obvious that most of the material written above applied to medical and surgical services, especially but not only acute services. Mental health services are different, precisely because there is no identifiable disease to be treated. Most if not all treatments in psychiatry focus on impairments, the symptoms and disturbed body functions (brain functions) associated with the disorder and/or the patient’s activities and/or their social functioning.

Therefore it is totally to be expected that people whose mental illness is so severe that hospital admission is needed will have much longer hospital stays. In those patients where their distress is the major concern, the need is to control symptoms. This may be done through pharmacological or non-pharmacological means, but in either case it will take weeks because that is how long it takes to achieve change at the level of impairment.

Many patients will be admitted to a mental health hospital primarily because their behaviour threatens their own safety or the safety of others. For example someone may be so withdrawn that they neglect their own well-being, or might be a high risk of suicide. Others might threaten other people secondary to mania, or paranoia. Whatever the aetiology, changing behaviour is likely to take well over a month because changing behaviour is a slow process.

A significant proportion of people with severe mental health problems have difficulties in social participation. Whether this is secondary to a disorder, or causally related to a disorder, it will often be necessary to try and improve engagement in social activities and the extent of a person’s social network. As the earlier analysis shows, this also takes a long time.

Last, it is evident that the management of functional disorders is centred on changing beliefs, increasing activities and increasing a person’s ability to manage their symptoms. There is no disease to cure. Although some patients are admitted to hospital, most are not. In either case, management takes considerable time, as would be predicted from the need to alter impairments and activities and, in some instances, social context.

Therefore the general relationships established between each system and timeframes in the context of illness arising from disease hold completely true in the fields of mental health and functional illness. The relationships support the initial hypotheses.

Palliative care

Palliative care encompasses both end-of-life care and control of symptoms. The latter is usually, but not only, in the context of dying.

The biopsychosocial theory of illness does not give any particular insights into time course in palliative care. Self-evidently the end-of-life phase of an illness is time-limited but it is difficult to predict its duration. Indeed, good palliative care medical care may well lead both to a better quality of life and a longer life, such that specific end-of-life care is no longer appropriate or needed. In the care home I work in, several people admitted for end-of-life care have survived years, with one returning home and another re-engaged in social activities,

In relation to the explicitly palliative aspects of palliative care services, it is often intractable pain that leads to the involvement of the service. The service is likely to be needed indefinitely because the pain is often associated with a progressive disease.

In other words, palliative care is often needed on account of a progressive disease usually towards the end of life, but the inherent uncertainties in medical prognostication mean that the time course is unknown. Once started palliative medicine involvement at some level will usually continue until death.

Service implications

This analysis has suggested that change in different systems occurs at different rates, getting slower as one moves from the biological systems (cells, and organs) through the functioning of the body, and out into goal-directed activities, with aspects of social participation being slowest. In terms of contexts, the rates of change are much more variable in the physical context, but are generally slow in the personal context and glacially slow in the social context. What does this mean for service design and delivery?

Historical prelude

History usually explains why something is as it is. Before analysing current services in the light of the analysis above, a look back into history might help.

Before Roman Times, most health problems were covered by a sick person being in touch with a healer. There were no services. The Romans organised their military extremely well, and a surgical service for wounded soldiers and slaves was developed based around valetudinaria which had a triage centre, and covered both acute and longer-term care.

A millenium later hospices (word derived from Latin hospitum, a place for hospitality) were developed for the ill and weary needing rest or protection. Hospices slowly transformed into hospitals for the more acutely unwell. In the nineteenth century, sanatoria were developed for the many people with long-term illness such a tuberculosis or mental illness.

As medicine progressed, hospitals became more and more focused on the acute diagnosis and, where available, treatment of disease. Long-term care no longer occurred in hospitals. Very large institutions were built for people with (presumed) mental health problems, and sanatoria primarily for people with TB persisted.

This very brief review illustrates that the distinction between immediate diagnostic and treatment organisations and long-term care organisations has been present for two millennia. Only in Roman times, when one organisation (the army) was responsible for both acute and long-term care of their soldiers, was there a close integration between early and late care. It also illustrates that hospitals, now focused on acute care, evolved from institutions once responsible for the long-term sick.

organisational timescales

Within health, the organisational focus is on short-term, high-speed diagnosis and treatment. Just under 90% of the NHS budget goes on secondary care in hospitals. In medical hospitals, the lengths of stay are measured in days; in mental health settings lengths of stay are longer but still measured only in weeks; and in the few identified rehabilitation settings and services that exist, the length of stay or service involvement is measured in weeks to a low number of months.

Secondary care does provide out-patient services. The great majority are single visits for some specific purpose. Some services, such as oncology or rehabilitation (usually just a single therapy), may have a programme of treatment. It is relatively rare to have a continuing long-term planned commitment to a patient – renal dialysis is one obvious exception.

In summary, the organisation of secondary care health services is predicated on single, defined relatively short episodes of care with long-term care needs being transferred to community services – general practice, other community health services, social services and nursing homes. Moreover they are predicated on the active involvement of secondary care specialist expertise not being routinely available ‘on demand’ or ‘as needed’ to people in the community.

The problem

The problem is probably obvious, but will be set out.

Patients present with a problem needing diagnosis and treatment. Diagnosing and treating this problem takes only a few hours or days in general. It fits in well with the timescales of hospitals; they have tailored their timescale to that required to make a diagnosis and give a specific treatment. At that point the person ‘no longer needs medical care’, even if unconscious. Medical care has been redefined to mean “specialist medical expertise exclusively related to diagnosis and cure or control of a disease”.

However, as shown above, changes in all other levels of a person’s illness are measured in anything from weeks to 12-24 months, or still longer. Many patients need not only care to maintain safety and well-being, but also active rehabilitation and management to ensure both the best outcome in terms of autonomy in activities and in terms of social re-integration, sometimes into new social settings.

The absence of any rehabilitation expertise, by which I mean a full multi-disciplinary team that works as a team, exacerbates the problem by failing to identify accurately a persons prognosis and needs.

The situation is further worsened by the extremely limited availability of expert rehabilitation services for people outside hospitals – in care homes, in community hospitals, and in their own homes. Moreover, the services that do exist are incoordinated and all run in different ways with different rules. (see here)

It should also be recognised that even medical, disease-focused services have considerable difficulties with the current organisational arrangements. Disease management is increasingly long-term, and often requires monitoring and adjusting by people with expertise. So far this need has been met by specialist nurses (not always actually nurses) who work across the boundaries, but this is not necessarily satisfactory for all people.

Funding arrangements have stifled innovation, and not only in the UK. The rapid changes in medical practice associated with Covid-19 demonstrate how severely bureaucracy and commissioning have prevented evolution of services to meet patient needs effectively and efficiently.

The ideal rehabilitation service

For many illnesses, and for most people admitted to hospital, disability is present from the outset

Therefore, management of the disability by an expert rehabilitation service should start from the outset. There are many a priori reasons why this should happen:

  • immobility cause muscle wasting, rapidly, and it takes a long-time to recover muscle bulk;
  • loss of practice at self-care is associated with loss of self-esteem and self-confidence;
  • absence of any planning leads to depression and dependence upon care;
  • and so on.

Early mobilisation is beneficial in the Intensive Care Unit (here), and early specialist rehabilitation assessment of swallowing reduces risk of pneumonia. (here). Very early mobilisation while acutely unwell may carry risk; active mobilisation in the first 24 hours after stroke may be risky. (here)

The implications for the structure of services and the structure of hospitals is clear. All hospital buildings must be designed and built to facilitate patients in retaining or regaining their ability to move and look after themselves even in intensive care. Moreover, all patients need to be seen by a rehabilitation service as soon as possible after admission. Third, the culture of the care environment must facilitate independence despite risks, which are often perceived and not actual.

Any patient who has a disability 48 hours after hospital admission should be seen by a rehabilitation service and have an initial rehabilitation plan, which may be quite short but, in more severe cases, could extend to a Rehabilitation Prescription, shown here. This plan should proceed in parallel with the disease diagnosis and management plan and, naturally, the needs imposed by the disease will have priority. Two benefits arise. Rehabilitation will lower the risk risk of secondary harm and disability arising, and it will increase the speed of recovery.

Patients will only remain in hospital until their care and safety needs can be met outside a hospital setting (see discussion on transferring patients out of a service here). Yet, when people with a persisting disability leave hospital (whether an acute medical hospital or a rehabilitation hospital), they will usually need continuing rehabilitation input to increase further their ability to function at home, in the community, or in work.

Unfortunately at present most people with significant disability at the point of leaving an acute hospital are likely to move through two or three different settings, and often twice as many therapy (or rehabilitation) services. Many patients will have very little active rehabilitation over and above an assessment.

Every move carries risk, but this would be minimised if the same team remained involved with a person as they move. Moves not only carry risk of harm, but they slow down or reverse progress, often for over a week, thus prolonging the episode of care (not to speak of any distress it may cause the person).

Therefore, a single service should be responsible for a patient’s rehabilitation from the time of onset or hospital admission until they are (once more) stable in their preferred long-term accommodation and no longer needing active input from the rehabilitation service. The only reason for changing services should be if the person is moving or needs to move to a different geographic locality.

Finally, even when someone’s situation has stabilised, if they have significant ongoing disability and care needs, they remain at risk of needing rehabilitation input. For example, if they develop an incidental other illness, or a carer changes and the new carer needs training, or if the underlying condition progresses, or if a family member leaves, or if the house needs changing, and so on and on. This they should be able to re-access the same service.

In conclusion, just as a patient expects to be cared for by the same expert medical service over time, wherever they are, so a patient should expect to see the same expert rehabilitation service wherever they are. At present this is not possible because organisationally and contractually the services are chaotic and incoherent. Even the few rehabilitation services available are short-term, whereas disability timescales are measured in months or longer. Medical services are now organising for long-term expert medical responsibility for and involvement with a patient. It is time that rehabilitation services were also organised to allow consistent expert rehabilitation for as long as it is needed.

Scroll to Top
%d bloggers like this: