Sleep: Poor sleep is a growing problem brought about through societal changes, including longer working hours and long commutes, shift work, and deteriorating work-life balance due to technology \citep{Luyster2012}. The NHS state that most adults need 6-9 hours of sleep per night \cite{2009}. This seems to be roughly in line with guidelines in the research literature. A recommended sleep statement from the American Academy of Sleep Medicine and Sleep Research Society \cite{Watson2015} had a panel of 15 experts review scientific evidence addressing relationship between sleep duration and health. They concluded that 7 hours or more sleep per night produces optimal health in adults. Sleeping less than 7 hours a night is associated with obesity diabetes, hypertension, heart disease, stroke, depression and increased mortality. Moreover, a recent prospective twin study \cite{Åkerstedt2017} found that both short (defined as <6.5 hours) and long (defined as ≥9.5 hours) were linked to increased mortality. However, it is important to note that these statistics are generalisations, with small groups of people fully able to function healthily on shorter periods of sleep. For example, research highlights that individuals with a mutation in the DEC2 gene required less sleep than their relations without this mutation \citep{Pellegrino2014,He2009}.  
Poor sleep is also associated with common mental disorders, while improving sleep in these patients can lead to mental health improvements \citep{Freeman2017}. Analyses on nearly 100,000 adolescents in Japan found a U-shaped association between mental health status and sleep duration \citep{Kaneita2007}. The authors also reported a positive correlation between mental health status and subjective sleep assessment. Similarly, among an elderly population, sleep problems were associated with worsened mental and physical health-related quality of life \citep{Reid2006}.
As with physical activity and diet, changes in sleep are associated with changes in vagal function, such that reduced vagal function (combined baseline and reactivity measures) is associated with sleep disruption \citep*{El-Sheikh2013}. Intriguingly, increases in resting state vagal function have been shown to predict better subjective and objective sleep quality \citep{Werner2015,Grimaldi2016}. By contrast, reduced HRV (as measured over a 24-hour period) has also been detected early during early stages of sleep-related breathing disorders \citep{Aeschbacher2016}. With respect to our GENIAL model \cite{Kemp_2017} and relevance to the following section on community, sleep deficiency and minor, day-to-day reductions in sleep trigger pathways to social withdrawal and loneliness. Poor sleep may be associated with cortical hypersensitivity to human contact, along with impairment in the capacity to recognise social intent \citep*{Ben2018}. Furthermore and relevant to our consideration of wider environmental impacts on individual wellbeing (see section \ref{479675}), nature has been used as an intervention to improve  sleep with promising results. For example, forest walking - involving positive psychological experience (e.g. positive emotions) and health behaviours (e.g. physical activity) - has been demonstrated to improve length and quality of sleep \citep{Morita2011}. It is also interesting to note that individuals who live closer to green spaces are more likely to achieve improved sleep duration (8 hours), even after controlling for well-known sleep influencers, including mental and physical health \citep*{Astell-Burt2013}.

Focus on Community

Here we focus on the relevance of community to individual wellbeing, a major focus of our original GENIAL model \cite{Kemp_2017}. The Japanese have a word to describe "lonely death"  -  ‘kodokushi’ - which refers to people dying without friends or family, and sometimes these individuals are not found for many weeks... or months. ("Dead people don't pay their bills"). Tragically, these experiences characterise the modern world,  and especially individualistic cultures. Social ties are deteriorating and loneliness is on the rise \cite{Kushlev_2017,Twenge_2013,twenge2014,putnam2001}, the reasons for which are complicated, but may involve a host of interconnected societal issues including generational shifts in narcissism \cite{Twenge_2013,twenge2014}, increasing individualism (versus collectivism) in western society \cite{Heu_2018,Brewer_2007}, and inequality \cite{Scheffer_2017,scheidel2017,r2010}. Critically, loneliness has important impacts on health and wellbeing. For instance, a meta-analysis of studies on more than 300,000 participants reported that a lack of social ties are associated with a 50% increased risk of premature mortality over a 7.5 year follow-up period, an effect that was stronger than physical activity, smoking (15 cigarettes daily) and body mass index \cite{Holt_Lunstad_2010}. In a more recent study on 48,673 participants, the same researchers \citep*{Holt-Lunstad2015} observed that social isolation (29%), loneliness (26%), and living alone (32%) increase risk for premature mortality, reporting no differences for objective and subjective measures. Furthermore, greater impacts on mortality were observed among those under the age of 65 years.  
Social isolation and loneliness may lead to ill-being via a host of behavioural, psychological and physiological factors. Associated behavioural factors include physical inactivity and smoking \cite{Shankar_2011}, substance use and hazardous drinking \citep*{Stickley2014}, while psychological factors include decreases in self-esteem, increased risk of depression, and feelings of hopelessness \citep*{Steptoe_2004}, contributing to a dysregulation of cardiovascular, metabolic, and neuroendocrine processes \citep*{Grant2009}, higher systolic blood pressure, independent of several factors such as age, gender, cardiovascular risk factors, medications, social support and perceived stress \citep*{Hawkley_2010}The NIACT \cite{Kemp_2017a} and GENIAL \cite{Kemp_2017} models integrate these behavioural, psychological and physiological factors into an innovative framework within which pathways to health and ill-health may be understood, bridging the gap between psychological moments and mortality. 
Further to our original GENIAL model \cite{Kemp_2017}, the relationship between social ties and health was recently comprehensively reviewed in a book titled 'The New Psychology of Health: Unlocking the Social Cure' \cite{2018}. Social identity theory helped to contextualise the research that was discussed, emphasising that people conform to the norms of the group to which they identify. Therefore, the actions and thoughts of the group become the reference point for the individual. If an individual's perception of others in a representative group is positive, individuals of that group will think and behave similarly. Peer modelling has proven to be an effective intervention to increase fruit and vegetable intake \cite{Horne_2008}, although only when modelled by someone that shares the same group identity \cite{Cruwys_2012}. By contrast, if an individual was to identify with a group whose health behaviours are risky, they are more likely to participate in negative health behaviours. Research has shown there is a relationship between strength of group identification and smoking status when smoking is a normal group behaviour \cite{Schofffild_2001}. Intriguingly however,  the more group identities an individual has, the less likely they are to engage in negative health behaviours, such as cigarette smoking, alcohol consumption, and use of illicit drugs \cite{Miller_2016}.            
Social identify theory provides a useful context within which to understand the individual. Social identity provides meaning, purpose and worth to an individuals life: the meaning hypothesis. Social identity facilitates the extent to which others are likely to provide social support (the support hypothesis). Social identity also provides a sense of efficacy, agency and power to an individual (the agency hypothesis), contributing to the sense that 'the whole is greater than the sum of its parts'. Strikingly, research has demonstrated that cardiac and respiratory patterns synchronise when members of a choir sing in unison, compared to when singing independently \citep*{Timmons2015}. This phenomenon of 'physiological linkage' may help to explain reduced relationship satisfaction \citep{Timmons2015} as synchrony of the sympathetic nervous system or HPA axis may underpin negative affective experience. Conversely, it may also help to explain XXX positive effects?? XXX  
To conclude, community is important for individual health and wellbeing as it provides the environment in which individual health and wellbeing may be achieved. A supportive community will therefore contribute to the health and wellbeing of individuals within that community, and this relationship will be a bidirectional one such that improved health and wellbeing of individuals will also foster community wellbeing. For instance, scholars have emphasised for example, that community resilience is underpinned by the individuals within it, highlighting the role of a positive outlook and individual strengths, which underpin a community's capacity for resilience and agency \cite{Berkes_2013}. Community resilience is a social-ecological system,  nested within different levels of a complex system - the 'symbioment' (see fig \ref{881013}) - which is (perhaps over-) simplified in the present paper to levels that include the individual, community and the environment. We now turn our attention to the wider environment in which individuals live and work, focusing on a major societal challenge to human health and wellbeing: anthropogenic climate change.

Focus on the Environment

Here we focus on contributions from the wider environment to individual wellbeing, and consider how different approaches to enhancing wellbeing may have beneficial or adverse impacts on the environment.
Psychological science has been criticised for a blinkered focus on the individual, while ignoring wider, systemic issues issues \cite{Carlisle_2009,Frawley_2015}. The ‘happiness industry’ has been described as egocentric, neoliberal socialism in which “sharing is preferable to selling as long as it doesn’t interfere with the financial interests of dominant corporations” \cite{davies2015}. Similar criticism has been made of the construct of wellbeing, which has been argued to be a socio-cultural construction of western individualism that places importance on wealth, fame and materialistic pursuits, while neglecting and disregarding our shared environment environment \cite{Carlisle_2009}. These criticisms in combination with the ever-increasing body of peer-reviewed literature on ‘happiness’ and ‘wellbeing’ were, in part, reason for proposing the original GENIAL framework \cite{Kemp_2017}, which extended theoretical frameworks of individual wellbeing to community wellbeing, and motivated us to consider how this framework might relate to one of the greatest challenges faced by mankind today: anthropogenic climate change. We use the term ‘environment’ in a very general sense, encompassing natural as well as human-built environments, although we place emphasis on the relationship between individual wellbeing and the natural environment given the sheer scale of the challenge associated with climate change.
Human beings have a strong, innate affiliation with the biological world, a phenomenon captured by the ‘biophilia hypothesis’ and exposure to nature can lead to transcendent emotions including the experience of awe and inspiring energy \cite{Bethelmy_2019}, peak experience \cite{1964} and psychological flow \cite{Csikszentmihalyi_2014}. Research also indicates that self-transcendent emotions - including compassion, gratitude and awe - foster healthy social relationships \cite{Stellar_2017}. Consistent with these conclusions other research demonstrates that spending time in nature facilitates social connections \cite{Mayer_2008,Richardson_2016}. Recent research indicates that people who spend at least two hours a week in nature are more likely to report good health and high high levels of wellbeing than those who spent no time in nature \cite{White_2019}. Furthermore, these findings were consistent across a variety of demographic variables including sex, age-group, occupational social grade, presence of chronic illness and whether or not individuals met physical activity guidelines. Other research has reported that exposure to nature is associated with stress reduction \cite{Hansmann_2007}\cite{Ulrich_1991}, feelings of restoration \cite{White_2013,Wyles_2017}, subjective wellbeing \cite{Johansson_2011,LUCK_2011,White_2017}, and improved cognitive functioning \cite{Berman_2008,Berto_2005}, the latter of which is regarded as a core outcome of health and wellbeing \cite{Friedman_2014}. Research also indicates that spending time in nature over a 2-week period boosts hedonic as well as eudaimonic wellbeing \cite{howell2014}, and that effect sizes are larger (ds from .37 to .63) than those reported for other positive psychology interventions (ds from .20 to .34) \cite{Bolier_2013}
The ‘biophilia hypothesis’ has been broadened to encompass non-living, physical elements, emphasising human affiliation with the local environment (‘place’) and a role for cultural experience \cite{Beery_2015,s2012}. This ‘topophilia hypothesis’ posits that human beings have a “genetically based drive for exploring the local environment… [that improves] the chances of the individual to survive and reproduce” \cite{Beery_2015}. The word topophilia combines topos (place) with philia (love) and was first used by the poet W.H. Auden in 1947. The experience of topophilia is increasingly being replaced by the experience of 'tierratrauma' (acute trauma associated with rapid and devastating change to a loved place) and 'solastalgia' (chronic place-based distress)  \cite{albrecht2019}. It is accepted in scientific circles \cite{change2007,change2014} that humanity will face catastrophic climate change should we fail to commit to climate action. An increase in the frequency, duration and intensity of extreme weather events increases risk of population distress and psychiatric disorders through disruption to food supply and damage to community wellbeing \cite{Berry_2009,Hayes_2018}. Extreme weather events have even been shown to influence the future health and wellbeing of an unborn child with implications for brain development and metabolic outcomes \cite{Dancause_2015,Dufoix_2015}. Research has also shown that climate change has population-weighted between-country inequality by ~25% over the last 50 years, with wealthy countries benefiting disproportionally \cite{Diffenbaugh_2019}. Increasing inequality as a host of pernicious effects on health and wellbeing including lower happiness, morality, social cohesion \cite{Buttrick_2017}, poorer health, higher mortality \cite{Buttrick_2017} and more terrorism \cite{Krieger_2010}.
The biophilia and topophilia hypotheses provide a foundation on which to understand the distress, pain or sickness associated with environmental degradation of home or territory. Glenn Albrecht, an Australian environmental philosopher coined the term ‘solastalgia’ after reflecting on the environmental impacts of open cut coal mining and pollution of local power stations on the residents of the Upper Hunter Region of NSW in Australia. He writes that ‘solastalgia’ reflects a “specific form of melancholia connected to a lack of solace and intense desolation” associated with place-based distress \cite{albrecht2005a}. Psychiatric disorders are also expected to arise from the direct and indirect effects of climate-related disasters through disruption to food supply and damage to community wellbeing \cite{Berry_2009,Hayes_2018}. In fact, the number of people experiencing psychological trauma following a disaster exceeds those with physical injury by 40–1 \cite{j2007}, and weather related disasters have increased by 44% since the year 2000 \cite{Watts_2018}. Critically, there is now strong evidence to conclude that we humans are contributing to such change, a phenomenon known as anthropogeneic climate change. Research reporting on ratings of peer-reviewed climate-science and self-ratings by climate change scientists themselves has indicated that there is 97% endorsement of humans contribution to the warming climate \cite{Cook_2013,Cook_2016}. Unfortunately, this finding remains under appreciated in a brave new world of alternative facts and disinformation \cite{Lewandowsky_2013,Lewandowsky_2017}.
In our original GENIAL model \cite{Kemp_2017}, we described an important role for positive social ties and community on health and wellbeing. Interestingly, others \cite{Beery_2015,Nurse_2010} have argued that the boundaries of ‘community’ should be extended to the environment including soil, water, plants and animals, in order to facilitate love and respect, and a commitment to environmental sustainability. Feelings of guilt, shame, fear, emotional discomfort and solastalgia have been associated with motivation to engage in environmental sustainability behaviours \cite{Albrecht_2007,DICKERSON_1992,Kaiser_2008,Malott_2010}. Others have proposed an ‘aesthetics of elsewhere’, which involves encouraging a double aesthetic judgment of ‘here’ and ‘elsewhere’ to induce an aesthetic melancholia to influence consumption decisions \cite{maskit2011}. Researchers have begun to investigate the positive psychology of sustainability \cite{Corral_Verdugo_2014,Corral_Verdugo_2012,obrien2016}, a strategy that may help to foster what has been described as sustainable wellbeing \cite{Kjell_2011}. In a study on 606 undergraduate students in Mexico \cite{fraijo-sing2011}, researchers reported that pro-ecological, altruistic, frugal and equitable behaviors reflect the sustainably-oriented person, and that these behaviours have positive psychological consequences. Prior research had shown that individuals engaging in pro-ecological behaviours – such as resource conservation – report greater happiness \cite{Brown_2005}, that altruism leads to greater long-term happiness \cite{ja1995}, and that frugality predicts greater psychological wellbeing, satisfaction and motivation \cite{Brown_2005}. More equitable individuals however, are reported to be less happy due to the ‘negative hedonic impact of inequality in society’ as climate change exacerbates existing inequities \cite{Hayes_2018}.
Others have proposed the concept of ‘sustainable happiness’ \cite{2016}, defined as “happiness that contributes to individual, community, and/or global well-being without exploiting other people, the environment, or future generations”\cite{obrien2010} thus differentiating it from phrases typically used in positive psychology such as “sustaining happiness” or “sustainable increases in happiness” \cite{s2007}. More recently, a structural model of the relationships between character strengths, virtues and sustainable behaviours has been presented such that all 24 character strengths \cite{p2004} are associated with all four sustainable behaviours (i.e. altruistic, frugal, equitable and pro-ecological behaviours) \cite{Corral_Verdugo_2015}. This body of work provides a useful foundation on which psychological scientists may advocate a role for their discipline in addressing environmental challenges, because pro-environmental behaviours also provide opportunities to promote happiness and build resources for resilience, in addition to much-needed environmental benefits \cite{Clayton_2016,fraijo-sing2011,Corral_Verdugo_2012}. The grave threat of anthropogenic climate change may also inspire a variety of positive feelings such as altruism, compassion, optimism as well as a sense of purpose “as people band together to salvage, rebuild, and console amongst the chaos and loss of a changing climate” \cite{Hayes_2018}, feelings that reflecting ‘active hope’ \cite{c2012}.
While the emerging positive psychology of sustainability \cite{Corral_Verdugo_2015,Kjell_2011,Corral_Verdugo_2012,obrien2016} provides a clear link between individual and environmental wellbeing, it is also notable that the vast majority of people do not engage in pro-environmental behaviours, a result of helpless and low self-efficacy \cite{Salomon_2017}. The difficulty in comprehending problems associated with climate change, and the intangibility and invisibility of such change may also lead individuals to sit on their hands and do nothing, a phenomenon known as ‘Giddens Paradox’ \cite{a2009}. Recent qualitative research \cite{langen2017} has investigated the psychological processes that foster these pro-environmental behaviours. Findings were interpreted in the context of ‘salutogenesis’ \cite{ANTONOVSKY_1996}, which emphasises a role for a ‘sense of coherence’ for managing and overcoming stress. This ‘sense of coherence’ reflect feelings of confidence that stimuli in the (internal and external) environment are comprehensible, manageable and meaningful. The researchers reported that grassroots activists relied on values and attitudes, emphasising that the problems are so vast that limits are imposed on knowledge (i.e. comprehensibility), arguing that emotions are a key mediator between the appraisal of a situation and motivation to take action. A sense of personal responsibility for change was associated with an improved perceived quality of life, attributable to empowerment and social cohesion, which provides a sense of meaning and purpose in life. Concrete and collective action was also observed to enhance positive emotions and mastery experiences subsequently enhancing beliefs about self-efficacy (i.e. manageability) \cite{langen2017}.
In summary, exposure to nature provides a host of benefits that have direct impacts on wellbeing - over and above the beneficial impacts of outdoor physical activity [XXX INFLUENTIAL REF?? XXX] - and may even promote commitment to pro-environmental behaviours. We have observed emerging research interest in the concepts of sustainable happiness and wellbeing, directly linking positive psychology to concepts relating to sustainability and pro-environmental behaviours.

4. The Updated GENIAL model: GENIAL 2.0

”Models, of course, are never true, but fortunately it is only necessary that they be useful”.
– George Box, 1979, Journal of the American Statistical Association, 74:365, 1-4
The GENIAL framework illustrates common pathways to ill-health and ill-being versus health and wellbeing. The evidence-base for these pathways - including a key regulatory role for vagal function - have been described previously \cite{Kemp_2017,Kemp2017,ah2018}. While our original GENIAL model highlighted the importance of positive social ties for individual health and wellbeing \cite{Kemp_2017}, our updated model (see Fig \ref{div-162276})  provides an important update to our original GENIAL model, emphasising individual, community and environmental contributors to personal wellbeing. In doing so, our model characterises the relationships between individuals, communities and their environments, as well as the impacts of sociostructural factors and their impact on the health and wellbeing of the individual, consistent with social-ecological theory. Key features of the individual, community and environmental domains are now briefly described with a particular focus on vagal function.
Individual wellbeing is promoted through positive psychological experiences and positive health behaviours. Meta-analyses have demonstrated that positive psychological interventions (PPIs) are effective for people with or without diagnosed disorders \cite{Bolier_2013,Hendriks_2019,Chakhssi_2018,Sin_2009,White_2019a}, with effect sizes ranging from small to large. Meta-analyses have further demonstrated the effectiveness of specific positive psychological interventions (PPIs) including the practicing of gratitude \cite{Davis_2016}, the ‘best possible self’ intervention \cite{Malouff_2016}, savouring positive emotions \cite{Smith_2014} and performing acts of kindness \cite{Curry_2018}  XXX meta-analysis of mindfulness? other strategies? XXX CLARIFY OUTCOME MEASURES??? XXXX. The three main models of psychological wellbeing \cite{Seligman_2018,Diener_1984,Ryff_1995} provide a theoretical foundation for developing new and novel interventions for enhancing positive psychological experience. Importantly, research demonstrates that despite the different theories that have been proposed for wellbeing, each of these contributes to the same higher order construct of wellbeing \cite{Goodman_2017,Disabato_2016}. In other words, there are many strategies through which positive psychological experience may be enhanced. Our recent review on vagal function \cite{Kemp_2017a} concluded that higher resting state vagal function is associated with positive mood states, highlighting the utility of positive psychology interventions for enhancing a key upstream regulator of health and wellbeing. It is interesting to note that that purpose in life has also been shown to predict allostatic load ten years later \cite{Zilioli_2015}as measured by the sum of seven scores across multiple physiological systems including cardiovascular, lipid, glucose metabolism, inflammation, autonomic function, and hypothalmic-pituitary-adrenal risk scores. Unfortunately however, this study did not distinguish between upstream and downstream systems driving increases in metabolic risk (i.e. vagal function plays a known regulatory role over inflammatory processes, as demonstrated previously: \citealt{Tracey_2002}). 
Focusing on health behaviours - including exercise, diet and sleep - typically involves consideration of one’s physical health, however recent high profile research has also highlighted the impact of positive health behaviours on mental wellbeing, supporting declarations that there can be no health without mental health \cite{Vladu_2016}. On a sample of 49 unique prospective studies (N=266,939), physical activity has shown to protect against depression, irrespective of age and geographic region \cite{Schuch2018}. In a cross-sectional study of more than 1 million individuals in the U.S. \cite{Chekroud2018}, exercisers displayed 43% fewer days of poor mental health than non-exercisers. The authors further reported that all exercise types were associated with a lower mental health burden (from 11·8% to 22·3% reduction), and the activities associated with the largest associations included popular  team  sports  (22·3%  lower),  cycling  (21·6%  lower),  and  aerobic  and  gym  activities  (20·1%  lower). Exercise duration of  45  minutes  and  frequencies  of  three  to  five  times  per week were associated with the lowest mental health burden. With respects to diet, other research XXX (INTEGRATE DIET - doi: 10.1038/s41380-018-0237-8, SLEEP: doi: 10.1093/sleep/zsz054) Critically, each of these health behaviours - physical activity, diet and sleep - have a powerful impact on vagal function \cite{Kemp2017}. As vagal function provides a structural link between physical and mental health, focus on positive health behaviours is a powerful means to promote health and wellbeing.
In addition to focusing on psychological experience and health behaviours, recent developments in psychological science have highlighted a key role for social relationships for the health and wellbeing of the individual. Therefore, individual wellbeing may also be promoted by focusing on community, the focus of our original GENIAL model \cite{Kemp_2017}. The implications of social relationships for the health and wellbeing of the individual were recently summarised in the recent publication of 'The New Psychology of Health: Unlocking the Social Cure' \cite{2018}XXX BRIEFLY DESCRIBE THE GROUPS4HEALTH PAPER BY CATHERINE HASLAM, AND ANY OTHER KEY STUDIES The work by Barbara Fredrickson and colleagues is also especially relevant here, emphasising the upward spiral of positive emotions, social connectedness and vagal function \cite{Kok_2010,Kok_2013}. XXX POLYVAGAL THEORY XXX SENTENCE ON VAGAL FUNCTION XXX the GENIAL model builds on well established theories of vagal function which include polyvagal theory.
Finally, our updated model emphasises the environmental context within which individual health and wellbeing is promoted and communities reside. Glenn Albrecht \cite{albrecht2019} provides a solid foundation for understanding the link between human emotion and the environment, coining numerous words to emphasise the negative and positive 'psychoterratic' states that have important implications for the health and wellbeing of individuals, communities and societies now and into the future. Environmental contributors include negative and positive psychoterratic states such as solastalgia (chronic place-based distress) and soliphila (a neutral political term for combatting solastalgia) \cite{albrecht2019}. A review of the literature on potential mechanisms linking nature to health identified 21 potential pathways empirically linked to nature \cite{Kuo_2015}. These pathways included environmental factors including phytoncides - antimicrobial volatile organic compounds with physiological effects - and vegetation filtering of pollutants, physiological factors such as elevation of vagal function and immune function, psychological factors involving positive emotions and attention restoration, and behavioural factors including positive health behaviours such as the promotion of physical activity and social ties. Interestingly, this paper suggested that enhanced immune functioning might reflect a central pathway for mediating the beneficial effects of nature on health. It is apparent however, that vagal function plays a regulatory role over immune function via the cholinergic anti-inflammatory response [REF]. Thus, we suggest here that vagal function will play a key role in not only regulating the beneficial effects of positive psychological experience, positive health behaviours, positive social ties, but also, the beneficial effects of nature on human health and wellbeing.  
In conclusion, our updated GENIAL model (fig \ref{div-162276}) summarises individual, community and environmental contributors to human health and wellbeing. Our model also characterises major clinical targets for potentially improving the wellbeing in people living with a host of chronic conditions and disorders, a topic to which we turn next. Clinical targets include psychological experience, health behaviour, social connections and outdoor nature-based activities to which the tools from positive psychology and behaviour change may be applied. We examine how clinicians might implement and sustain positive change in our discussion on facilitating behaviour change in section \ref{225494}.