Implications for Chronic Conditions and Non-Communicable Disease

Chronic conditions include diabetes, obesity, cardiovascular disease, cancer, chronic respiratory diseases, some neurological conditions and mental health conditions. Chronic conditions are also referred to as non-communicable disease (NCDs) (Non communicable dise...). The global burden of disease attributable to NCDs has now outstripped the burden of communicable conditions (Fig 1), a phenomenon known as the 'epidemiological transition'. The worldwide increasing burden of chronic conditions (Fig 1), treatment gaps and treatment lag \cite{Wang2004,PATEL_2010} are major obstacles to be overcome. The treatment gap refers to the numbers of people who need treatment that are not receiving it. As an example, the treatment gap for mental health disorders has been estimated to exceed 50% in all countries of the world, and to reach 90% in those with less resources \cite{PATEL_2010}. The amount of time taken to receive mental health treatment when it does exist—treatment lag— has been estimated to be longer than a decade \citep{Wang2004}.
 
As a function of this epidemiological transition, healthcare systems are struggling to meet increasing demand (Guzman-Castillo et al., 2017). In the United Kingdom (UK), it is estimated that approximately 30% of the UK population have one or more chronic conditions and that this 30% accounts for 70% of the spend (Department of Health, 2012). People living with chronic conditions are the biggest users of the National Health Service (NHS). They are more likely to see their general practitioner (accounting for approximately 50% of consultations), to be admitted as inpatients and to use more inpatient days than those without such conditions (70% of all inpatient bed days), and account for 64% more outpatient appointments (Department of Health, 2012).  Our theoretical models of health and wellbeing allow several inferences to be drawn regarding health care for people with chronic conditions. 
 
Models of health care: Despite the epidemiological transition, healthcare models have not adapted to the changed landscape. The dominant model of health care, ‘the acute medical model’ was designed to treat acute conditions. Inherent in the medical model are several assumptions that are ‘not a good fit’ when applied to people with chronic conditions. For example, the acute model is underpinned by the assumption that a person’s ‘acute problem’ can be fixed and that they can be returned to a ‘pre-injury state’. However, chronic conditions cannot be fixed and whereas impairment may be reduced to some extent, a healthcare approach that attempts only to reduce symptoms misses opportunities to promote wellbeing. The absence of illness or impairment does not equate to wellbeing, and interventions which focus only on reducing impairment are insufficient to tackle the challenge of chronic conditions. With reference to our framework we argue that by building positive psychological experiences (e.g. individual strengths, optimism and resilience) within a supportive social network and environment, pathways to self-sustaining cycles of positive health and wellbeing may be triggered and maintained, supporting and facilitating wellbeing despite the limitations imposed by the condition. Accordingly, the management of people with chronic conditions requires a holistic approach both within the health service and beyond – an approach that extends beyond a) medicine which by definition is the science and practice of establishing diagnosis, treatment and prevention of disease; and b) the health service given major determinants of health are influenced by the communities and the environment we live in. Another assumption of the medical model is that patients are ‘passive recipient of care’. However, treatment outcomes for people with chronic conditions are contingent on active collaboration between clinician and patient. For example, adherence to treatment regimens, and adoption of recommended lifestyle changes etc. With respect to interventions to promote psychological experiences, interventions cannot be 'done to the patient' and successful outcomes depend on an active and collaborative approach. 
 
Organisational and institutional barriers within health services and beyond: Epidemiological studies have shown that common mental health disorders and physical diseases are strongly inter-connected, highly co-morbid and share critical pathways to ill health and disease (Druss, Walker, 2011 ), (O’Neil 2015). This evidence has been captured by the tagline: 'there is no health without mental health' (Prince 2007). As an example, the senior author on the current review (AHK) investigated the relationship between the mood and anxiety disorders and coronary heart disease (CHD) in Brazil (Kemp 2015), observing that these common mental disorders are associated with a threefold increase in CHD, after full adjustment for potentially confounding factors. Common mood disorders share an underlying diathesis whereby mechanisms that predispose individuals to depression and anxiety for example, contribute to the development of a range of chronic physical health conditions across the life span, and vice versa. While the mechanisms for such a relationship are complex, our work on this topic (Kemp 2017, Kemp 2017a, Kemp 2018, Kemp 2013, Kemp 2016) - including our GENIAL model (Kemp 2017) - have emphasised a role for vagal function as a mediating link between mental and physical health (Kemp 2017, Kemp 2017a, Kemp 2018, Kemp 2013, Kemp 2016). A greater appreciation - and understanding - of the relationships between mental and physical illnesses and their underlying mechanisms are needed so that improved interventions and treatments may be developed which bridge the gap between physical and mental health services. Accordingly, this tight interconnection between physical  and mental health needs to be reflected in the models, infrastructure and commissioning of health services that support people with chronic conditions.  For example, relative to physical health conditions, mental disorders are much less likely to receive treatment and this holds true across the world \citep{2009a}. However, if one considers the global burden of chronic conditions in terms of disability rather than mortality, major depression is the second leading cause of disability \citep{O_Neil_2015} preceded only by cardiovascular disease. Moreover, there is a high degree of co-morbidity with mental and physical health conditions and we know that mental ill health affects adherence to treatments and prognosis \citep{Robin_DiMatteo_2002}. Accordingly, the commissioning bias in favour of physical health services actually disadvantages the majority of people with chronic conditions given the tight linkage between physical and mental health and serves to exacerbate the challenges for the prevention and amelioration of chronic conditions.
There are also biases in the types of interventions offered by mental and physical health services (with the exception of pharmacological treatment). People with physical health difficulties are typically prescribed physical health treatments. For example, people with cardiovascular disease (CVD) are typically advised to partake in healthier diets and physical activity. However, we know that there is a strong reciprocal relationship between CVD and depression \cite{Gasse_2012,Kemp_2015}. This bias misses several opportunities to enhance health and wellbeing for people with CVD. For example, positive psychological experiences have been associated with decreased risk of secondary cardiovascular events and mortality \citep{Boehm2012}\citep{DuBois_2015}. It has been argued that psychological wellbeing is a modifiable protective factor that could decrease the impact of CVD through its potential influences on health behaviours and CVD-related biomarkers \citep{DuBois_2012}\citep{Sin_2015}. Conversely, mental health services typically focus on offering psychological therapies in addition to medication whereas much research has shown that people with mental health conditions have poor diets \citep{Storlien_1996a}, disturbed sleep (Lee 2012, Ancoli-Israel 2006), lower levels of physical activity \cite{Goodwin_2003} and social isolation \cite{Dom_nech_Abella_2019}. Moreover, interventions that target these health behaviours significantly ameliorate symptoms (Trauer et al., 2015),  \citep{Stathopoulou_2006}(Opie et al., 2015; Parletta et al., 2019).  Given that undesirable health behaviours contribute to the aetiology and amelioration of chronic conditions; a plethora of guidelines and recommendations regarding optimal diet, physical activity etc. have been developed (for a summary, see Table 2). Often treatment approaches for people with chronic conditions includes educating them about healthier life choices. Despite such education, the majority of individuals fall short of pursuing a healthier lifestyle \cite{Newsom_2011}.
Evidence shows that such strategies have minimal impact upon inducing sustained change, especially in individuals of a lower socio-economic status \cite{Angermayr2010}.  That is, 'common knowledge is not common action'. There is an inherent disconnect between what people know and what they do - often referred to as the intention-behaviour gap (Sheeran, 2002). It is this intention-behaviour gap that creates a barrier to the uptake of evidence surrounding well-being activities into healthcare practice \citep{Francis2012}. This is because successful change requires more than education or communication of personalised risk information \citep{French2017}. Accordingly, in order to better understand how to effectively target health behaviours we must move beyond giving information and attempt to better understand how to facilitate behavioural change. Moreover, our GENIAL framework demonstrates that social relationships offer a target for intervention that is typically not exploited by the health service despite research showing that a) people with chronic conditions are often socially isolated and, b) a lack of social ties predicts premature mortality to a greater degree than physical activity, smoking (15 cigarettes daily) and body mass index \cite{Holt_Lunstad_2010}.  Accordingly, interventions which seek to foster positive social ties may have much to contribute to tackling the challenge of chronic conditions. This may be achieved by creating networks based on collaborations between the health service and community organisations, with both parties having a theoretical and applied understanding of how to create environments that promote social connectivity and wellbeing - we describe an example of this from our own clinical practice below. 
The original GENIAL framework highlights individual pathways to illness and premature death and health, wellbeing and longevity. When negative, health behaviours, psychological experiences and social ties (social relationships, integration and cohesion) contribute to the aetiology of chronic conditions and exacerbate the condition when present. Accordingly, we have argued that they should be targeted in the prevention and amelioration of chronic conditions. Given that the health service is typically organised by 'disease specific' services as discussed above, and given that health behaviours, psychological experiences and social ties offer a common target for intervention across a range of diseases, we advocate for a transdiagnostic approach to management. That is, creating a balance between the need for disease specific 'specialisms', but also for transdiagnostic approaches that treat some of the common diathesis that many people with chronic conditions share (undesirable health behaviours, negative psychological experiences, social isolation and exclusion). This approach would mean that people with chronic conditions would be able to access interventions based on need and efficacy not diagnosis. Transdiagnostic services would hold expertise in; a) interventions for optimal sleep, nutrition and  adapted physical activity interventions couple with an understanding of promoting behavioural change; b) links with the community to facilitate community integration and positive relationships with others; c) psychological interventions to both reduce impairment, but also to improve wellbeing; d) links with academic institutions to promote urgently needed cross disciplinary research into effective management strategies. With a mind to the financial difficulties facing the health service, the addition of transdiagnostic services would negate the need to resource and skill-up all diagnostic specific services to deliver interventions targeting heath behaviours, psychological experiences and social connectivity. Moreover, in relation to bridging the gap between the health service and the community, this would be difficult for diagnostic services to do in reality. 
Finally, our extended GENIAL 2.0 framework makes it clear that in order to promote the health and wellbeing of entire populations, the healthcare cannot and should not shoulder the burden alone. We present a range of compelling evidence that the health and wellbeing of individuals are not just determined by individual factors alone, and that community and environmental determinants of health must also be targeted to reduce the burden imposed by chronic conditions. This requires a shared understanding of the problems and solutions and joined up working between the healthcare services, community organisations and academia. Our own work in the National Health Service has focused on re-developing our services for people living with acquired brain injury.  In addition to traditional impairment focused services, we are developing interventions to improve wellbeing, social relationships, community integration and social identity in addition to some interventions that involve environmental sustainability. We are doing so in collaboration with academic institutions as well as community, third sector and industry organisations. This service development, based on our GENIAL framework, has application across chronic conditions. We discuss our work further in the following section and draw some conclusions.

Discussion

Here we have presented a modern understanding of wellbeing; one that involves 'connection'... connection to ourselves, to others and to the environment. We suggest that vagal function provides an important mediator of wellbeing that affects and is affected by activities to promote wellbeing across these multiple domains. The vagus nerve connects us to ourselves (i.e. 80% of vagal nerve fibres are afferent nerves \cite{Agostoni_1957} providing a structural link between mental and physical health), to others (increases in vagal function facilitate a 'calm and connect' response promoting social connectedness, \cite{Porges:2011wv,Kemp_2017,Kok_2013}), and to nature (vagal function is impacted on by a host of environmental factors, as discussed in section \ref{170385}, that will subsequently promote individual health and wellbeing). Vagal function may be considered as an index of resilience, underpinned by psychological flexibility \cite{Kashdan_2010} that can be enhanced through a variety of interventions within individual, community and environmental domains, providing a target for focused interventions. We suggest that benefits to vagal function could be maximised by drawing upon multiple interventions that span these multiple domains of wellbeing. While we have been greatly influenced by the maturing discipline of positive psychology, we argue that the field has been limited by a restricted focus on strategies that promote positive psychological moments and experience. As recent research has argued that the impacts of positive psychological interventions are smaller in size than previously reported \cite{White_2019a}, we argue that their impact could be improved by integrating interventions that also focus on physical health, which we now know to have important impacts on mental - in addition to physical - health \cite{Chekroud2018}. Integrating interventions within community and environmental domains will likely improve the impact of interventions further. It is also important to note that wellbeing can be influenced through sociostructural factors such as governmental policy, a consideration highlighted in our original GENIAL model \cite{Kemp_2017} (see section \ref{605389}). Our updated GENIAL model (section \ref{170385}) further extends beyond the individual and community, to incorporate the broader impacts of the environment. Mindful of previously proposed social ecological theories such as Glenn Albrecht's work on 'Earth Emotions' \cite{albrecht2019}, which emphasise the connectedness between human emotions and the state of our natural environment, we emphasise that the individual is intimately connected to the community and environment within which they live, in a 'symbioment'. In this regard it is interesting to observe calls \cite{Bratman_2019} for the modification of the natural environment in ways that will promote the mental health of communities, with research even demonstrating relationships between urban tree density and numbers of antidepressant medications prescribed \cite{Taylor_2015}. Researchers have also argued that sociostructural changes aimed at improving the natural environment will further contribute to improvements in wellbeing through the reduction of inequalities \cite{Bratman_2019}. As noted earlier, income and welath inequalities have substantial impacts on societal wellbeing, and this topic is now the subject of major international and interdisciplinary reviews on the subject (e.g. the 5-year Deaton Review: https://www.ifs.org.uk funded by the Nuffield Foundation).  
Over the last few years, we have developed a novel 8-week positive psychotherapy intervention (see table \ref{544962} for a summary of individual components) built on our innovative GENIAL framework, incorporating interventions that focus on the individual, community and environmental domains. Presently, we are working with university undergraduate students and people living with acquired brain injury, although we are seeking to broaden our focus to patients with a variety of chronic conditions including for example, diabetes, obesity, cardiovascular disease, common mental disorders and their comorbidity. Interventions focusing on the individual include activities from positive psychology (section \ref{407732}) as well as education relating to positive health behaviours (section \ref{138512}). Interventions involving the community domain focus on building positive relationships with others in line with social identity theory \cite{2018}, supported by partnership working with community organisations, such as "Surfability" (https://surfabilityukcic.org/) and "Bikeability" (https://bikeability.org.uk/), which serve to encourage community integration (section \ref{417151}). Finally, interventions focusing on the environment include activities such as mindful photography, as well as partnership working with the community organisation, 'Down to Earth' (https://www.downtoearthproject.org.uk/). This organisation promotes wellbeing in disadvantaged populations through engagement with the environment, especially in regards to environmental sustainability and social ecology. For instance, our patients with acquired brain injury were recently involved in the construction of a 'community building' using sustainable and locally sourced raw materials on the Gower Peninsula, the first place in Britain to be named an Area of Outstanding Natural Beauty. These are just some selected examples to illustrate the potential to promote wellbeing in each of the domains, and we are always seeking to engage with other academic groups, health boards and community organisations to improve health and wellbeing in the community, based on strong theoretical foundations.