However, self-efficacy beliefs do not operate sufficiently in isolation to changing one's behaviours \citep*{bennet2016}. Rather, its effects are moderated by outcome expectancies and the value placed on the behavioural goal \citep*{French2013}.
Whilst self-efficacy offers a buildable construct that can facilitate change, there is evidence to suggest that positive affect may offer a better predictor of long-term adherence to positive health behaviours. A meta-analysis of 82 studies indicates that positive affective attitudes are stronger predictors of engagement (relating to physical activity in this instance) than positive cognitive attitudes or levels of self-efficacy
Rhodes, Fiala, & Conner, 2009); an effect sustained relatively long-term in even individuals previously naïve to such health behaviours (
Williams et al., 2008;
Williams, Dunsiger, Jennings, & Marcus, 2012). Positive affect, in part, comprises a motive for enduring change (Kwasnicka, Dombrowski, White, and Sniehotta, 2016). Integrating evidence on positive affect with that on implicit process,
\citealp*{Van2018} present the
upward spiral theory of lifestyle change to address the mechanisms through which positive affect alters future health-related decision making. Here, positive affect experienced during health behaviours are considered to increase non-conscious motives for those health behaviours. This creates an implicit incentive salience and prompts everyday decisions to repeat desirable actions. In line with the broaden-and-build theory (Fredrickson), positive affect builds a suite of endogenous vantage resources over time, comprising biological resources (e.g., cardiac vagal tone) as well as cognitive (e.g., mindfulness), psychological (e.g., purpose in life), and social (e.g., positive relations with others) resources
Fredrickson (2013). This further facilitates the positive affect experienced during positive health behaviours and strengthens non-conscious motives; predicting future engagement in health behaviours
Rice & Fredrickson, 2017, and resulting in behavioural maintenance. Particularly, interventions aimed at increasing positive affect simultaneously facilitate the building of social connections. For instance, training in loving-kindness meditation
\citep{Kok_2010,Kok2015,Kok2013} elicits positive emotion and this is moderated by baseline vagal tone. Increases in positive emotion lead to subsequent increases in vagal tone, mediated by an increase in the perception of social connectedness. Higher vagal tone predicts greater social engagement at follow-up, and higher social engagement in turn predicts further increases in vagal tone
\citep*{Kok_2010}. This reflects a self-sustaining upward spiral between vagal function, emotion and social connections.
The research conducted by highlights the important contributions of a variety of individual, community and environmental factors to the maintenance of positive health behaviours; with viable theoretical explanations to assist in the elucidation of potential mechanisms. However, models to date seldom address the needs and characteristics of individuals with chronic conditions and thus have minimal applicability regarding the context in which interventions for these populations are derived. In order to truly facilitate well-being, mechanisms proven to cultivate lasting positive change are pivotal \citep*{Rusk_2017}. To this end, \citet*{Rusk_2017} present the theory of Synergistic Change to describe the pathways through which interventions (particularly relating to positive psychotherapy) cultivate lasting positive change in its recipients, and, subsequently, facilitate wellbeing.
The Synergistic Change Model (SCM) is based in complex dynamics systems theory (Thelen, 2005) and emphasises the complex interplay of dynamic elements that facilitate lasting positive change in functioning. These elements comprise of five psycho-social ' Domains of Positive Functioning'
(Rusk and Waters, 2014), including: attention and awareness, comprehension and coping, emotions, goals and habits, and relationships and virtues; further to environmental and biological/physiological influences (Rickard & Vella-Brodrick, 2014). The SCM suggests that whilst each of the psycho-social domains operate independently (Rusk & Waters, 2015), each element may also interact and influence functioning in all other domains; working to either reinforce or undermine change.
According to the SCM, interventions may result in one of three processes of change: relapse, spill-over, and synergy. ‘Relapse’ may occur when changes in one domain are inadequate, unstable, and made to one of two domains in isolation. Isolated changes are less likely to change the overall dynamic stability of the psycho-social system and instead results in between-domain interactions which undermine and prohibit initiated change within a given domain. Thus, individuals revert to their original state of undesired functioning. In contrast, spill-over occurs when the effects of positive change in one domain "spill over" to enhance functioning in other domains. Spill over effects from enhancements in one domain on to another are often reported in qualitative investigations of patient experiences (Landsman-Dijkstra, van Wijck, & Groothoff, 2006) and may be evidenced as mediation effects within the literature (Toussaint & Friedman, 2009). Spill-over effects demonstrate that cognitive functions do not operate independently and offer insight as to how different interventions may result in similar changes being accomplished through multiple pathways of pursuit (Oman, Richards, Hedberg, & Thoresen, 2008). However, these residual effects are often temporary and offer no promise of sustainable change. To induce enduring change, mutually supportive and reinforcing changes must occur within several domains of psycho-social functioning. These synergystic interactions result in a new dynamically stable pattern of behaviour; typically referred to as upward positive spirals (Ryff & Singer, 1998; Crawford & Caltabiano, 2011; Gudan, 2010; Lyubomirsky & Layous, 2013; Wood, Maltby, Gillett, Linley, & Joseph, 2008) and identified as mechanisms through which interventions may enhance well-being (Cohn & Fredrickson, 2010). According to the SCM, the formation of these synergistic spirals is a powerful means by which the effect of an intervention can be made enduring; and that interventions will be more effective if they are designed to produce synergistic change.
Considering features central to sustained positive change, \citealp{Rusk_2017} highlight several strategies that can be adopted to facilitate interventions; including targeting pivotal domains, leveraging existing strength’s and values, and targeting mutually reinforcing elements. Briefly, pivotal elements are those domains that can initiate synergistic changes that ‘tip the system into a new stable mode of functioning’ (Rusk et al., 2017). For example, positive emotions are considered pivotal elements that create ‘upward spirals’ that broaden thought-action repertoires, build psychological and social resources and foster positive emotions futher (Fredrickson & Joiner, 2002; Fredrickson, 2004; Garland et al., 2010). Consequently, interventions that cultivate positive emotions may trigger synergistic changes within a range of psycho-social domains that enhance and sustain benefits to well-being. Further to this, intervention strategies should be tailored to an individual’s traits, values or character strength’s profile; leveraging these to support the desired change through synergistic interactions. Lastly, the SCM (Rusk et al., 2017) suggests that change within a given domain of psycho-social functioning, particularly non-pivotal domains that lack synergistic potency, will be more successful if mutually reinforcing domains are targeted to foster synergistic change and stabilise functioning. Moreover, the SCM suggests that targeting elements of psycho-social functioning from the behaviour change literature (e.g. implementation intentions, self-efficacy) in addition to elements from, for instance, the positive psychology literature (e.g. gratitude, optimism, or mindfulness) may further induce enduring change. Thus, the SCM holds the potential to integrate the knowledge captured within existing behavioural change theories to bear in creating positive psychological change.
Sustained behaviour change is vital when working with populations with chronic conditions, and whilst interventions largely demonstrate the potential to facilitate well-being \citep*{Sin2009}, outcomes are often short-lived and participants often revert to pre-intervention levels of functioning at follow-up assessment \citep*{Seligman2005}. Despite the advantages of theory, behaviour change interventions are seldom designed with reference to theory \citep{Davies_2010,Prestwich_2014}. In fact, a meta-analysis of 235 implementation studies reported that only 22.5% explicitly used constructs of behaviour change theories \citep{Davies_2010}; and often loosely and inadequately so \citep{Painter_2008,Prestwich_2014}. However, there remains a lack of guidance on how to select an appropriate theory for a particular purpose \citep*{Michie_2008}, with a predominance in published intervention evaluations of a small pool of traditional theories painter\citep{Painter_2008}. Models currently used in public health and behaviour change interventions largely emphasise and target individual factors, such as motivation, whilst broader social and environmental variables are far less likely to be considered \citep*{Glanz_2010}. This occurs despite evidence suggesting that beneficial effects produced by complex interventions are strongly linked to context \citep*{Tarquinio_2014} and national guidance summaries concluding that behaviour change interventions are more effective if they simultaneously target variables at individual, community and population levels (NICE, 2007). A comprehensive approach to health promotion thus requires changing the practices of social systems that have widespread detrimental effects on health. If we are to contribute significantly to the betterment of human health, we must broaden our perspective on health promotion and disease prevention beyond the individual level \citep*{Bandura_2004} and draw upon a wider range of theories than currently used. Crucially, theories should be suited to the characteristics of the target population, behaviour and context; else the potential benefit of using theory is limited \citep*{Davis_2014} .
Discussion
Here we present 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 health and wellbeing that is impacted on 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 argued in section
\ref{170385}, that will subsequently promote individual 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. 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. Given that 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. I
t 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{464010}). 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 for
city planners to consider modifying the natural environment in ways that will promote the mental health of communities \cite{Bratman_2019}, 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 if targeted at ways to reduce inequalities \cite{Bratman_2019}. Inequalities - be they due to income, wealth, ethnicity, or geography - have substantial impacts on societal wellbeing and are 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 the 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{489909}) with a focus on how these mental and physical activities might be sustained over the longer term drawing upon theories of behaviour change (section
\ref{225494}). 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.