Abstract
Significance of the Research
This study is significant because it traces the historical shifts in how both nature and YMH have been conceived, showing how these evolving meanings have shaped the design and aims of outdoor therapies. By tracing historical shifts in these ideas and uncovering ideological continuities within this complex field, the study offers educators and researchers critical tools for developing more integrated, ecocentric experiential learning practices.
Outdoor Therapies and Youth Mental Health: A Historical Perspective
In its 2021 report, the World Health Organization (WHO, 2021) underscores that “mental health and subjective well-being were positively associated with all green space types, except for gardens (only neutral outcomes)” (p. 16). The organization stresses the importance of preserving and supporting these spaces as key contributors to health and well-being. Similarly, the idea of outdoor activities being used to increase youth mental health (YMH) has a relatively long history. Without explicitly mentioning YMH from the last third of the nineteenth century onwards, institutions such as sanitoria and the scouting movement flourished as means of promoting a return to a more ‘natural’ way of life through being immersed in green, outdoor spaces. Despite the evolution of outdoor programs designed to improve YMH that have emerged over time, the history of these transformations and perceptions associated with outdoor therapies for YMH has yet to be written. We borrow Harper and Dobud's (2021) term outdoor therapy, which can be defined as any institutional, political, or scientific initiative aimed at improving mental health through actively engaging the body in natural environments. We use this term to refer specifically to outdoor therapeutic approaches that focus on YMH. While outdoor therapies have a long historical foundation, concerns about YMH have grown markedly in recent decades, making it a pressing public health issue today.
Youth Mental Health: A Growing Public Concern
Mental Health First Aid (MHFA, 2020) estimates that one-quarter of the global population is affected by mental health disorders annually. Mental illness is not only a sign of social malaise, but also the cause of many of its consequences. Mental health disorders are risk factors for morbidity and mortality (United Nations, 2025), while placing a significant psychological burden on those around them and contributing to large-scale economic demands (WHO, 2021). These disorders are often born out of unfavourable socio-economic environments (Moitra et al., 2023; Tesli et al., 2021).
Approximately 75% of mental illnesses affecting mental health begin during adolescence (Kessler et al., 2007). While mental illnesses are generally less severe in children, they can develop into more serious, undetected conditions, which, over time, may become chronic (Kessler et al., 2007). Experiences that foster mental well-being help people to build resilience, better manage life's stressors (Hooley et al., 2017), and mitigate potential future mental health deterioration (Tesli et al., 2021). However, mental health within youth as a distinct population has only been a subject of interest since the second half of the twentieth century (Levine, 2015). While institutions for ‘mad people’ or other severe cases have long existed (Foucault, 1963), more insidious pathologies were neither recognized, detected, nor adequately measured (Levine, 2015). Interest in mental health pathologies has significantly increased over the last 30 years, making them one of the major issues of this century (Moitra et al., 2023). This growing interest can be explained in part by the marked decline in YMH levels throughout the twenty-first century. This trend accelerated during the COVID-19 pandemic, as evidenced by the U.S. Surgeon General's Advisory, which called for more research to help understand the socio-cultural context of this crisis (U.S. Department of Health and Human Services, 2021).
The Outdoors: A Remedy for Youth Mental Health
Today, references to a beneficial return to nature for mental health have permeated the public sphere. Culturally, but also scientifically and politically, several movements have emerged in the twenty-first century, reflecting a growing interest in the relationship between nature and YMH. Take, for example, Louv's (2008) term nature deficit disorder or the political support for friluftsliv culture in Scandinavia as a means to promote YMH (Gurholt, 2014). Even more significantly, global organizations such as the WHO strongly encourage immersion in green spaces, as they are believed to have positive effects on both physical and mental health (WHO, 2021). The implementation of outdoor programs that support YMH may seem self-evident in light of this broad social interest. However, these kinds of programs did not simply emerge in the past two decades as the result of a sudden collective awareness; they are rooted in a historical trajectory that directly informs current practices.
The Evolution of Research on Outdoor Therapies
Alongside the increased attention to YMH, another research domain has focused on capturing the implementation of therapeutic interventions in nature. Outdoor therapies first emerged in the 1960s and developed as an alternative to traditional methods for addressing mental health pathologies. Over nearly 60 years, the peer-reviewed literature on the relationship between YMH and nature has grown considerably and is now extensive, and the number of therapeutic modalities identified has become extremely high (Meichenbaum & Lilienfeld, 2018). While the benefits of nature-based approaches on various psychological parameters are widely accepted (Annerstedt & Währborg, 2011; Bratland-Sanda et al., 2019; Cason & Gillis, 1994; Harper & Dobud, 2021), an initial look at the literature suggests that the articles appear as a succession of re-examinations of closely related topics. This apparent stagnation can partly be explained by the explosion in the number of intervention models, which leads to a perpetual return to exploratory studies aiming to answer the same question: Does this program improve YMH outcomes? For example, the effect of the outdoor program on self-worth and competence (Clifford & Clifford, 1967); the effect of the outdoor environment on self-concept (Ewert, 1977); the effect of wilderness camping on behavior (Sachs & Miller, 1992); and the resulting health effects of greenspace exposure (Twohig-Bennett & Jones, 2018).
This recurrent focus on similar phenomena has been noted by several authors, who emphasize that the field suffers from fragmentation and a lack of cumulative knowledge. Harper and Dobud (2021) highlight the difficulty of building a coherent epistemological or empirical foundation, as each approach develops its own frameworks, references, and methods, which have little systematic dialogue between them. Similarly, Gass et al. (2020) point to the limited cross-fertilization between outdoor therapy models, while Bowen and Neill (2013) note the recurrent use of exploratory and small-scale designs that prevent the accumulation of generalizable knowledge. More recently, Fernee et al. (2019) have stressed the lack of shared theoretical and methodological frameworks as a barrier to the field's scientific maturity. Together, these studies underscore how this apparent stagnation is not merely an artifact of program diversity, but a reflection of deeper structural and epistemological challenges within the field.
A Semantic Framework for Understanding the Evolution of Outdoor Therapies
This inquiry aims to bring clarity and coherence to what currently appears as a varied and complex set of approaches in outdoor therapy research. The historical dimension of this study seeks to clarify the epistemological tendencies within the field of outdoor therapies and to better understand how therapeutic approaches have been constructed over time. Ultimately, we hope that identifying shared ideological foundations and historical shifts in meaning will make dialogue between program designers, providers, and evaluators, more possible. To this end, the study analyzes the semantic trajectory of outdoor therapy's two structuring concepts: YMH and nature. Adopting a historical and semantic lens thus offers a way out of the epistemological impasse identified above. By tracing how nature and YMH have been successively redefined, we can uncover the intellectual and social conditions that have shaped the diversity of approaches in outdoor therapy. These meanings, often implicit in literature, are found in discourses and evolve with the norms and ideals of their time. A discourse, in this sense, refers to a way of speaking and thinking that reflects how a society understands the world (Foucault, 1969/1992). Clarifying these discourses is essential for building a shared conceptual language across programs and a more robust understanding of how outdoor therapies have developed since the 1960s.
Method
Design
This inquiry employed a two-step investigatory design. First, we conducted a narrative review (Sukhera, 2022) to identify and assemble the relevant body of peer-reviewed literature on outdoor therapies. Narrative reviews aim to describe what is known on a topic and to conduct a subjective examination and critique of the entire body of literature.
Second, once this corpus had been established, we applied a mixed-methods analytical approach within the collected material to trace the evolution of the field over time (Petticrew & Roberts, 2006). The quantitative component consisted of descriptive analyses of factual elements—such as target audience, program type, and the role attributed to nature—in order to trace the historical trajectory of outdoor therapies for YMH. The qualitative component involved a theoretically driven Foucauldian discourse analysis, drawing on The Archaeology of Knowledge (Foucault, 1969/1992), to identify the conditions of emergence and the ‘moments of rupture’ in the discourse—that is, the periods when the meanings associated with nature and YMH changed.
Inclusion Criteria
In this review, the “participants” were not human subjects but rather the academic articles included in the corpus. The eligibility criteria for articles were intentionally broad due to the flexible lexicon employed within outdoor therapies. Indeed, the vocabulary used, target audience, and methods employed vary according to the theoretical frameworks and behavioural ‘issues’ that the therapies and the researchers addressed. The list of eligibility criteria for this narrative review in the initial stages was guided by the PCC approach, which considers population, concept, and context (Pollock et al., 2023). In this review, the population includes individuals aged 11 to 25; the concept refers to the effectiveness of outdoor therapies on YMH; and the context focuses on outdoor exposure.
Materials
Data collection took place throughout June 2024 and comprised two databases: EBSCOhost (https://search-ebscohost-com-443.web.bisu.edu.cn/) and Google Scholar (https://scholar.google.com/). The latter was specifically used to gather articles not accessible via the EBSCOhost database. The search strategy included the following keywords: (“youth mental health” OR “psychological well-being”) AND (“outdoor education” OR “wilderness therapy” OR “nature-based programs” OR “outdoor therapy”). Only peer-reviewed journal articles in English were included. Following Renn's (2019) framework for the historical formation of knowledge fields, we compensated for potential omissions in the electronic searches by tracing the earliest publications on outdoor therapies by manually reviewing the reference lists of the included systematic reviews and meta-analyses. Numerous studies were identified through this approach (n = 49). From electronic and manual reviewing, several distinct but overlapping branches of research could be distinguished, including wilderness therapy, adventure therapy, outdoor education, and nature-based mental health programs.
Procedures
The standardized PRISMA method (Figure 1) was applied to detail the article selection process, which began with the initial PCC framework. The PRISMA 2020 flow diagram was created using the PRISMA2020 R package (Haddaway et al., 2022). Potentially relevant articles were first selected based on their titles and abstracts. After reviewing these 97 articles, the final selection of the most relevant ones was made according to two criteria.
PRISMA 2020 flow diagram of the study selection process. Note. PRISMA flow diagram of the study selection process, created using the PRISMA2020 R package and Shiny app (Haddaway et al., 2022).
The first criterion was consistency with the PCC framework, which ensured that the studies were relevant to the population, concept, and context of our review. The second criterion involved a qualitative assessment of the study's contribution to knowledge. Of course, using a qualitative evaluation introduces potential biases in judgment (Kmet et al., 2004). While methodological quality was considered, we aimed to balance rigor with the informational and contextual richness of the studies. This was particularly important for older, often exploratory works that do not meet current methodological standards yet provide valuable historical insight into the early development of the field of outdoor therapies. To support this flexible process of evaluation, the Joanna Briggs Institute (JBI) critical appraisal tools were used (Lockwood et al., 2015; see Appendix A). The authors worked independently to select the articles. Instead of assigning a numeric score to each appraisal item, the quality of each study was described qualitatively in terms of confidence: low, moderate, or high. Articles with a low level of JBI confidence were excluded, while for studies rated as moderate, the authors consulted each other to assess their relevance and importance. This approach ensured that studies were not excluded solely due to methodological limitations and were assessed for their overall contribution to the field. Following this final processing of the database, 49 articles were included in the review.
Analytic Strategy
The generation of categories followed an iterative process combining inductive and deductive reasoning, in line with the principles of qualitative content analysis (Mayring, 2014). The analytical work was conducted by both researchers. The first author performed the initial data extraction using summary tables that included general information such as location, study design, target population, gender distribution, study objectives, therapeutic approach, the role of nature, and how the authors explained improvements in YMH (Tables C1–C3). Based on this material, both researchers independently reviewed the preliminary categories to assess their coherence and completeness. They then met to discuss their interpretations of the data and to agree on the most appropriate qualitative categories. These preliminary categories were subsequently refined deductively, drawing on the theoretical framework and existing literature on outdoor therapies, ensuring that the final classifications were both empirically grounded and conceptually coherent (Fereday & Muir-Cochrane, 2006). From this process, three key analytical dimensions emerged: the type of condition studied, gender distribution, and the role attributed to nature.
For the first factor, namely the type of pathology, the articles were classified into four categories according to the populations studied. The first category, young offenders, refers to individuals whose practices are deemed illegal. The second, social disruptors, includes those considered to exhibit excessively aggressive, intimidating, or physically or psychologically harmful behaviour. The third, non-social disruptors, concerns individuals with diagnosed mental health problems (e.g., anxiety, obesity, depression) or difficulties in social relationships (e.g., family conflicts). Finally, the fourth category, without mental health diagnosis, includes studies featuring participants who do not have any mental health diagnoses and are not involved in the justice system.
Regarding gender distribution, we counted the number of males and females participating in each study when such information was available. No non-binary category was included, as only one participant identified as such in the entire corpus (Norton et al., 2023).
Finally, the role of nature was categorized according to three types of approaches. In the first, nature is active, meaning that nature is understood to play an agential role in fostering a sense of well-being and improving young people's mental health. In the second, nature as a sporting arena, the natural environment merely serves as the backdrop for the program, holding no intrinsic value and functioning solely as setting and ‘combatant’. The third approach, labelled ambiguous, was used when it was not possible to determine whether the role of nature was active or merely that of a sporting arena—usually because elements of both perspectives were present.
The inquiry's findings are divided into three periods: 1962–1990, 1990–2005, and 2005–2020. The first and last periods show a relative stability in the semantics of the terms nature and YMH, while the second period represents a transition, that is, a “moment of rupture” in the discourse (Foucault, 1969/1992). To understand how semantic shifts in nature and YMH shape outdoor therapies, each epoch is analyzed according to three categories: type of program, the role of nature, and participant characteristics.
Results
A Hostile Nature for Deviants (1962–1990)
Type of Program
The first articles reporting research on outdoor therapy programs for YMH emerged in the 1960s. Apart from two studies conducted in New Zealand and Australia in the 1980s, every study within our literary corpus from this first epoch until 1990 (13 studies) is from the United States (Table C1). Within this Anglo-Saxon cultural backdrop, the first programs were delivered by Outward Bound. Indeed, Outward Bound had a monopoly on outdoor therapies until the 1980s. From 1962 to 1990, they accounted for 69% of the articles and served as the inspiration for 84.6% of program designs within the corpus. Outward Bound's origins lie in the UK during World War II, where programs were created to mentally prepare young mariners for enduring the horrific challenges they faced (Veevers & Allison, 2011). The first American school was established in Colorado in 1962 and reflected Hahn's oft-quoted aims of developing “an enterprising curiosity, an undefeatable spirit, tenacity in pursuit, readiness for sensible self-denial, and above all compassion” (Golins, 1980, p. 7). In these programs, participants were confronted with challenges in which the development of physical strength, psychological resilience, solidarity, and self-transcendence were at the core of the project. Values of perseverance and camaraderie were subsequently conveyed and had a lasting influence on the outdoor therapy programs that followed (Clifford & Clifford, 1967; Kelly & Baer, 1969). This heritage is reflected both in the perception of nature, as well as in the types of pathologies targeted by these programs and their gender distribution.
Nature's Role in YMH Enhancement
Among the 13 articles from this first epoch, 12 describe nature as a sporting arena (92.3%). Conversely, no study considers nature as playing an active role in contributing to the improvement of YMH (Table 1). Much as Brookes (2006) notes, natural landscapes were considered “empty sites on which to establish social or psychological projects” (p. 34) and merely served as a backdrop for these kinds of programs. The environment in which adolescents were placed was not seen as possessing an intrinsic virtue; it was viewed as an indifferent setting in which they must excel. The ‘hostile’ characteristics of the physical environment thus aim to foster feelings of going beyond previously known personal boundaries and the development of physical and psychological strength. It is through this kind of self-transcendence that young people, apparently, improve their mental health. The articles reveal a semantic field centered on physical vigour, encountering risk, and overcoming the hostility of nature. These elements are evident in Clifford and Clifford's (1967) description of an Outward Bound course: Each patrol engages in a variety of vigorous physical conditioning exercises, ranging from bathing in a cold mountain stream in early morning to running, axemanship, and climbing. The object is to build physical stamina and to push each individual to his physical limit. (p. 241) Moments of danger” that are “embedded in the ‘daily’ requirements of persistence
Our observations about the role of nature in the early outdoor therapies for YMH coincide with the prevailing view of nature in modern societies. In articles from the first epoch, nature is presented as a sporting arena; a clear distinction exists between the natural world and the one cultivated by humans. On one side, there are safe and controlled spaces made possible by society and, on the other, landscapes which are largely untouched by human activity, which then become hostile environments that participants must learn to master. This distinction is typical of a modern anthropocentric worldview, in which humans are regarded as a hierarchically superior species and nature is “valuable only insofar it is valuable to human beings” (Casas & Burgess, 2012, p. 184). Consequently, early Outward Bound programs perpetuated an anthropocentric view of nature. The programs embodied the rationalist perception of the Earth system, which, by postulating a strict division between nature and culture, reduces nature to its most inert and immobile form (Dutreuil, 2024). From this perspective, the environment in which the participants evolve is not a dynamic actor with which we interact, but an obstacle to overcome.
Participant Characteristics
In this section, we demonstrate how the characteristics of the previously mentioned outdoor therapies and the population they target are interdependent. The discourse in the articles on these programs, which emphasizes the rationalization of nature, physical strength, and resilience, is directed at young men either on the margins of society or identified as social disruptors. In the 11 studies conducted between 1962 and 1990, gender distribution was highly unbalanced (Table 1). Women only appeared in 1975, but, even then, remained a minority. In total, until 1990, males numbered 570, accounting for 87% of participants, while females numbered 84, making up 13%. When facing nature, “the important ingredients of character are: autonomy, the desire to serve others, courage, personal discipline, a realistic self-image, resourcefulness, willpower, and an appreciation of nature and man's [sic] place within it” (Kelly & Baer, 1968, p. 107). These statements imply that—irrespective of one's biological sex—surviving in the wilderness demands exercising masculine traits. Bourdieu (1998) links masculine identity to values like strength and control, which also arguably underpin Outward Bound's approach. Similarly, Rosenthal (1985) shows how institutions like the Boy Scout movement attempted to shape character by instilling discipline and social norms that would reinforce these masculine ideals, which instructors would then seek to perpetuate. For example, Baer et al.'s (1975) findings show how educators subjectively assessed the program's effect on participants using five categories: effort, maturity, leadership, extraversion, confidence, and physical ability. Once again, we observe echoes of masculinity that must be asserted in nature.
In terms of the various pathologies on which outdoor therapies are focused, among the 12 articles specifying the type of pathology, five addressed young offenders, two focused on adolescents deemed anti-social, one examined youths with poor academic performance, and four dealt with what could be considered ‘healthy’ populations (Table 1). The latter category was considered thus because there were no indicators suggesting they were anything other. A trend in this first epoch involved trying to measure “what change, if any, occurred in young offenders’ self-concepts and attitudes toward social adjustment after participation in a survival training course” (Kelly & Baer, 1969, p. 719). Most studies from this period evaluated the impact of the program on self-concept and ‘deviant’ behavior 1 . Regardless of the participants’ characteristics, outdoor programs were positioned as vehicles for facilitating social integration. The underlying hypothesis appeared to be that the harshness of nature would instill discipline and rigour in those who were not conforming to society's ideals of a young person who was socially well-adjusted. This perspective suggests that being immersed in a hostile natural environment highlights, by contrast, the relative stability of society (Baer et al., 1975; Kelly & Baer, 1968). At the time, the concept of YMH was primarily associated with young offenders whose behaviour deviated from social and legal norms. This approach promoted a holistic integration of youths into society through outdoor activities. Over time, the target audience expanded to include not only young offenders but also those whose behaviour did not align with more refined standards of socially accepted ‘normality’ (Rosenthal, 1985). Abnormal behaviours were linked to ideologies or pathologies that often manifested in opposition to institutions, particularly schools, and thus caused a certain instability in the public domain. For example, Stick and Senior's (1984) study examined young offenders, schizophrenics, mood disorders, neuroses, personality disorders, and drug addiction.
Between 1962 and 1990, outdoor therapies primarily targeted young men, most of whom were on the fringes of society. The majority of programs were run by Outward Bound (or were influenced by them) and were largely founded on the premise that improved mental health would be elicited through positive experiences of mastery in challenging natural environments. At this point, nature served principally as a backdrop for shaping the psychology of ‘deviant’ youths—young offenders and social disruptors alike.
Diversifying Programs and Participants (1990–2005)
The second epoch of outdoor therapies for YMH spans from 1991 to 2005 and features 17 papers (Table C2). This pivotal period is hallmarked by a greater breadth of activities, which came about as the result of two synergistic effects. First, the concept of nature gained increasing importance within academic debates, as its role within the programs had thus far received limited attention. The second effect is the expansion of the very concept of YMH, which led to a diversification of the target audience for these programs. This broadening of the audience pertains both to the greater representation of women and to the types of pathologies considered.
Type of Program
The early 1990s mark the beginning of a gradual shift in the three characteristics we have observed: the type of program, the role of nature, gender distribution, and the pathologies studied. These transformations are all interconnected and were arguably shaped by broader socio-cultural movements.
The first, and most visible, change within the 1990s was the increased diversity of program types (Table 2). Between the first and second periods, there was a move from two to six types of programs: Outward Bound, Wilderness program, Adventure, Outdoor Behavioral Healthcare, Horticulture therapy, Greenspace immersion—all of which presumably feature considerable overlap. Furthermore, in the second period, the distribution of program providers was much more varied, with only one article based on Outward Bound (7.1%). We should not view these observations as a radical break from the past, but rather as a reshaping of existing course provision; although Outward Bound no longer held the monopoly on outdoor therapy provision, many of the newer initiatives were directly influenced by them. Indeed, 72.4% of the articles mention that they were inspired by Outward Bound. There is thus a strong legacy from the early programs, along with a need to redefine them, as notions of nature and YMH evolve toward more ecocentric and inclusive frameworks.
It becomes quite clear that, starting in the 1990s, the programs were no longer exclusively focused on social integration—namely, reinserting marginalized youth into normative social frameworks—as they were with Outward Bound. They incorporate exploratory and recreational dimensions, such as adventure therapy (Hattie et al., 1997); horticultural therapies, emphasizing a more sensory aspect of the outdoor experience (Perrins-Margalis et al., 2000; Richards & Kafami, 1999); programs with family and educational aims (Sachs & Miller, 1992; Wilson & Lipsey, 2000); and programs addressing public health (Grahn & Stigsdotter, 2003). This diversification of provision arguably led to a certain instability within the field. As early as 1992, Gillis notes a definition problem that is confusing practitioners and researchers: “The use of different and multiple measures, at different times, for different definitions results in alternative outcome criteria to decide what indeed does work” (p. 37). Thus, although studies agree on the effectiveness of nature-based programs, it remains difficult for outdoor therapies stakeholders to answer simple questions, such as: What works? For whom is it effective? What is nature? In short, our initial analysis of this second epoch highlights the diversification of program types and the issues these initiatives address. We now discuss the underlying factors lying at the origins of this transformation and their implications for empirical research.
Nature's Role in YMH Enhancement
As explained at the beginning of this section, the transformations of the 1990s are interconnected and should be understood in tandem rather than separately. Indeed, while the increase in the number and variety of outdoor therapies is arguably only a reflection of changing attitudes towards the role of nature and of YMH in late twentieth century society.
Between 1962 and 1990, nature was portrayed as a sporting arena in 12/13 articles (92.3%). Between 1990 and 2005, representations became more evenly distributed across three categories: Sporting arena, Active, and ‘Ambiguous’ (Table 2). This shift led us to introduce the ‘ambiguous’ category during the coding process, as the role of nature became increasingly difficult to classify (Russell, 2003; 2005; Sachs & Miller, 1992). Explicit references to mastering the environment, central in earlier programs, faded during this second period, and nature's role often appeared implicit or merely suggested. The literature highlights contrasting views on the role of nature and how this, alongside the increasing variety of approaches found in outdoor therapies, is closely linked to the philosophical debates surrounding the concept of nature in the 1990s. During this period, theories emerged in the social sciences that challenged both the modern conception of life and the nature/culture Cartesian dualism (Dutreuil, 2024). The rationalist approach, prominent in earlier programs with their emphasis on mastering nature (Baer et al., 1975; Kelly & Baer, 1968; Marsh & Richards, 1986), gradually gave way to more dynamic and relational understandings of the natural world. For example, in the horticultural therapy studied by Perrins-Margalis et al. (2000), participants reported that “using brightly colored flowers, enjoying the fragrances of flowers and herbs, and feeling the texture of the soil” (p. 28) contributed to enhancing their overall well-being. Although this shift was not widespread, it opened space for alternative perspectives in which nature could be seen less as a ‘passive’ backdrop and more as an active program ‘participant’. Following Gibson (1979), natural spaces brought affordances that offered all beings myriad possibilities for perception and action.
These subtle and often implicit changes in the conception of nature appear to have increased the diversification of outdoor therapies for YMH. The program designers were likely unaware of the underlying philosophical and cultural assumptions informing their practices, as representations of nature are frequently shaped by unconscious thought patterns (Cocks & Simpson, 2015). Programs thus reflect diverse and sometimes conflicting approaches. While some continued to draw on earlier rationalist legacies, others, such as horticultural therapies (Perrins-Margalis et al., 2000; Richards & Kafami, 1999) and green space interventions (Grahn & Stigsdotter, 2003), embodied emerging ecocentric tendencies that emphasized interdependence and mutual responsiveness between humans and nature. However, because the role of nature within these programs was rather fluid, ambiguous, and often implicit, it became difficult to clearly understand its place and function within them.
Participant Characteristics
We have seen that the diversification of outdoor therapies for YMH from the 1990s onward can be partly explained as a disruption of the concept of nature. Another part of this explanation lies in the meaning and place of YMH in society.
Our findings highlight a broadening of the types of pathologies targeted by the programs. Indeed, the proportion of articles focusing on young offenders decreased from 47.7% in the first period to 14.3% in the second (Table 2). At the same time, articles concerning non-social disruptors increased from 8.3% to 28.6%. From the 1990s onward, there was a more balanced representation of different types of pathologies. Consequently, YMH interventions sometimes targeted ‘deviants,’ and other times a broader, non-specific population. However, the programs differed according to the types of pathologies. On the one hand, for young offenders,—such as sexual offenders (Lambie et al., 2000), violent youth (Sachs & Miller, 1992; Wichmann, 1991), or individuals with substance use disorders (Kennedy & Minami, 1993)—there was a continuation of traditionally masculinist values such as strength and control, in combination with a sporting arena view of nature, as observed in the programs from the first period. On the other hand, for non-social disruptors, such as those with chronic mental health conditions (Perrins-Margalis et al., 2000) or no specific pathology (Grahn & Stigsdotter, 2003), discourses and practices moved towards a more integrated understanding of nature—one that plays an active role in fostering well-being.
These observations coincide with the growing interest in YMH during the 1990s, when a collective awareness of YMH issues emerged (McGorry & Mei, 2018). This phenomenon was reflected in public health policies, with governmental reforms concerning YMH appearing and then intensifying in the early 2000s (McGorry & Mei, 2018). As a result, the political and social diffusion of YMH was reflected in its own broadening semantics; YMH thus came to refer to a wide variety of psychological disorders with rather ambiguous boundaries, that were mirrored in the provision of outdoor therapies, as reflected in Table 2. But how and to what degree are young women and people who are non-binary compatible with these programs, which traditionally operated under the banner of masculinity?
Representation of Factors Between 1962 and 1990 (13 Studies).
Note. For each pathology and role of nature, the number indicates how many studies fall into each category, while the percentage of female participants refers to the total sample size.
Representation of Factors Between 1990 and 2005 (17 Studies).
Representation of Factors Between 2005 and 2025 (19 Studies).
While the first epoch of outdoor therapies for YMH was marked by the absence of female participation, the second epoch shows a significant increase in their presence, which jumped from 12.8% to 29.9% between studies from 1962–1989 and 1990–2005 (Table 2). Moreover, among the 11 analyzable studies, 10 included females compared to only three out of 10 during the first epoch. Not only did females remain a minority, but their reported pathologies were often different than those of their male counterparts. For example, males are over-represented in studies featuring social disruptor individuals. The increasing number of females represented in the corpus accompanied the rise of new, more ecocentric programs and the broader definition of YMH. They are more present when nature is portrayed as an active agent fostering inner peace and when YMH targets a wider audience (Grahn & Stigsdotter, 2003).
Towards Active Nature and Extension of YMH (2005–2025)
This final section examines outdoor therapies for YMH from 2005 to 2024 and features 19 papers (Table C3). During this epoch, we discuss how the continued diversification of programs is made possible by both the continued transformation of the semantics of nature, which became perceived as being more active, and where YMH in general began to occupy an increasingly larger and less stigmatized position within public consciousness. These two fundamental processes allowed the programs to be available to an increased diversity of audiences, particularly women. However, the legacy of the early outdoor therapies remains present in more recent literature and thus complicates our ability to fully understand contemporary research and practice.
Type of Program
In this third epoch, the diversification of programs intensified. Among the 17 studies from this period, there are twelve different kinds of outdoor therapies for YMH. Furthermore, the dissemination and diversification of these programs has not been limited to Anglo-Saxon countries; programs emerged in other parts of the world, particularly in Europe and East Asia (Lee et al., 2008; Twohig-Bennett & Jones, 2018). With this expansion, new programs were influenced and redefined by local cultures and issues (e.g., YMH therapy based on Scandinavian friluftsliv (Fernee et al., 2019)). The expansion of outdoor therapies into new cultural contexts, and at a different historical moment, has gradually weakened the influence of the original Outward Bound programs. The corpus reveals a literature increasingly referring to, for example, ‘wilderness programs’, ‘outdoor therapies’, or ‘green space exposure programs’—all terminologies that obscure considerable conceptual and methodological diversity (Mitten in Harper & Dobud, 2021). The ubiquity of these generic terms makes it difficult for both therapists and researchers to distinguish between labels that have remarkable similarities and overlaps.
Nature's Role in YMH Enhancement
As with the second epoch, there are manifold changes linked to the meanings of nature and YMH. The most recent epoch presents a predominantly active view of nature within 78.9% of the articles (Table 3). Indeed, not a single article portrays nature as a site for exploitation and proving bravery. In these more recent outdoor therapy programs, nature is no longer a mere setting, but rather plays an active role as an agent in the therapeutic process. Corazon et al. (2010) explain how in “nature-based therapy, the environment is never just a background; it is the catalyst for the therapeutic process” (p. 42). It is through immersion in nature that individuals feel and absorb the surrounding elements, experience a sense of peace, and ultimately increase their mental health levels (Cooley et al., 2020; Norton et al., 2023; Revell et al., 2014; K. Richards et al., 2023). One can view this approach as being framed within a post-humanist perspective, where nature is seen as active and agentic (see Ingold, 2011; and Clarke & Mcphie, 2014). This ontological position aligns with critical movement against modernity, which opposes modern anthropocentric narratives of nature (Dutreuil, 2024; Latour, 2015).
Although the academic discourses surrounding nature have changed, there are a number of factors suggesting that discussions about a wholesale shift in semantics should be approached with caution. First, the transition in language is observed in the specific field of outdoor therapies for improving YMH, and our observations suggest that it is not shared by the entire academic community. Ongoing debates within the academic community about the role of nature are a clear indication that no consensus on this topic exists. Moreover, the influence of the legacy of the anthropocentric view of nature, so dominant in epoch one, is ongoing. Even though some studies emphasize the importance of developing a connection with nature, we still find a logic of ‘domination of humans over nature’ in some articles. The empirical analyses support Mitten's (in Harper & Dobud, 2021) critiques of the conflation of patriarchal and neo-colonial outdoor therapy practices with the emergence of a movement towards programs that can be characterized as being ecocentric. This tension is also evident in Harper et al.'s (2007) work, which highlights “Wilderness as a healing factor…” (p. 115)—suggesting an active role for nature in the therapeutic process—while emphasizing that human interactions lie at the core of the treatment. The articles in this epoch contain few direct references to nature in the therapeutic process itself.
Participant Characteristics
The articles from 2005 onwards reveal a trend among the pathologies studied (Table 3). While in the previous epoch, the proportion of pathologies was balanced between the four categories (young offender, social disruptor, non-social disruptor, and without a mental health diagnosis), in recent years, programs have focused more on non-social disruptors (47.18%) and those without mental health diagnoses (41.18%). In contrast, no study focuses on young offenders, and only two out of 17 involve disruptive youth. The most common study participants suffer from stress, diabetes, depression, psychological trauma, or addiction (Annerstedt & Währborg, 2011; Corazon et al., 2010; Fernee et al., 2019; Harper et al., 2007; K. Richards et al., 2023), or young people with no identified pathology (Cooley et al., 2020; Revell et al., 2014; Tillmann et al., 2018; Twohig-Bennett & Jones, 2018).
Finally, the data show that the increasing proportion of female participants from the 1990s has continued into the third epoch, accounting for 57.3% of the participants since 2005 (Table 3). The significance of this shift cannot be overstated, as there was a complete absence of women in outdoor therapies in the 1960s. Arguably, changes in gender distribution and the target audience are both witnesses to, and outcomes of, a profound transformation in the conceptions of YMH and of nature. Indeed, it would appear that the rejection of the masculine and anthropocentric discourses of the early programs has opened-up possibilities for females and for those with a wide array of pathologies to participate in outdoor therapies. However, the distinctions between nature being active, as opposed to a sporting arena, or between a broader or narrower understanding of YMH, do not appear so clearly in the literature.
Discussion
This narrative review highlights the diversification of research conducted on outdoor therapy programs designed to increase youth mental health since the 1960s (Figures B1 and B2). Through a comparison of three historical periods, referred to as “epochs,” the review shows how changes in the semantics of both nature and YMH have played a key role in this diversification. From the 1990s onwards, the meaning of YMH gradually expanded, while new discourses promoting a more ecocentric vision of nature increasingly permeated the field of outdoor therapies. Today, YMH concerns the general youth population, and most academic discourses describe nature as playing an active role in the therapeutic process, which further reflects this ecocentric perspective.
The semantic evolution of these terms has led to the inclusion of a wide range of adolescents across genders, regardless of whether or not they have a diagnosed mental health issue. Leaning on Foucault (1969/1992), the analysis of these archives revealed, first, a ‘regularity of meanings’ during the initial period, followed by a discursive rupture from the 1990s onward, which transformed the semiological system of outdoor therapies for YMH. Finally, the most recent years do not appear as a new discursive regularity but rather suggest a coexistence of diverse meanings associated with research and practice—what Foucault (1969/1992, p. 217) might describe as a ‘suspension of the temporal sequence’ (suspense des suites temporelles) within discursive regimes. Rupture—understood as the succession of semantic fields—never unfolds linearly. Instead, it reveals a diachronic transformation arising from the interweaving of discourses, leading to an uncertain outcome. This uncertainty underscores the need for ongoing semantic vigilance, which we call for in this review.
Although the meanings of the terms nature and YMH vary across different articles and periods, both researchers and therapists often blend different interpretations of these terms within the same program. This is the case, for example, with some programs adopting an ecocentric discourse, while championing practices based on physical challenge and competition between individuals (e.g., Becker, 2010; Russell, 2005). Despite this ecocentric turn (Figure B3), the legacy of early Outward Bound models—which promoted masculine values like strength and control over nature—still appears in subtle ways across the literature. These values persist, first, in the references used by authors (e.g., Annerstedt & Währborg, 2011), and second, in the practices proposed in certain studies (e.g., Margalit & Ben-Ari, 2014). Semantic transformations and diversification have made this field increasingly complex to navigate, as the boundaries between personal development, education, and therapy—and between nature and wilderness—have blurred.
Over many years, scholars have highlighted the lack of cumulative knowledge and the fragmentation of the outdoor therapy field (Bowen & Neill, 2013; Fernee et al., 2019; Gass et al., 2020; Gillis, 1992; Harper & Dobud, 2021). The findings of this review suggest that this fragmentation cannot be reduced to a mere collection of inconsistent research approaches; rather, it originates in long-standing tensions between two coexisting semantic spaces. Indeed, our analysis clearly highlights a major semantic rupture in the history of outdoor therapies. First, between the 1960s and the 1990s, discourses about nature predominantly describe it as a sporting arena used to strengthen masculine discipline and correct social deviance—a vocabulary that appears repeatedly in Outward Bound programs, early wilderness initiatives, and evaluation studies of the period (e.g., Baer et al., 1975; Clifford & Clifford, 1967; Golins, 1980; Kelly & Baer, 1968). Second, from the 1990s, we observe a progressive reframing of nature's role, which increasingly appears as a therapeutic agent in its own right—most notably in the literature on horticultural therapy or green-space exposure (e.g., Bezold et al., 2018; Corazon et al., 2010; Fernee et al., 2019; Richards & Kafami, 1999). However, this transition is neither synchronous nor linear; traces of a masculine and anthropocentric discourse continue to persist in the 2000s and remain partially visible today. This indicates that the semantic rupture unfolds as a diachronic process marked more by the incremental layering of discourses than by a radical transformation. In this sense, the historical perspective offered here confirms and deepens structural critiques of the field, which has long struggled to establish a shared empirical foundation (Fernee et al., 2019; Harper & Dobud, 2021).
Limitations of the Present Study
This narrative review is subject to several limitations. First, as with all narrative reviews, the processes of selecting and interpreting documents introduce potential bias. Although the PCC framework, PRISMA flow, and JBI appraisal tools were applied, the inclusion of both peer-reviewed studies and other types of sources inevitably resulted in uneven methodological quality across the corpus. This was particularly true for the earliest publications, which were largely exploratory in nature, and reflect the emerging status of outdoor therapy at the time. Several authors, including Bowen and Neill (2013), have similarly noted the difficulty of incorporating certain studies into reviews due to methodological inconsistencies, limited population information, or insufficient reporting.
Second, it would be inappropriate to undertake a semantic and epistemological analysis without acknowledging the authors’ own positionality. Scholarly discourse is always situated in, and shaped by, its temporal, spatial, and ideological context. In this case, both authors are nature-loving individuals with a strong interest in issues relating to young people's personal and social development. Such personal orientations may influence data interpretation and create blind spots or predispositions toward certain analytical directions (Davies, 2008). While every effort was made to maintain rigour and critical distance at each stage of the research process, a degree of partiality remains inherent and should be recognized.
Third, this review was limited to English-language publications, which may have excluded relevant contributions from other linguistic and cultural contexts. As is the case for many studies in this field, this restricts the generalizability of the findings, even though outdoor and adventure therapy programs are increasingly implemented in non-English-speaking countries.
Implications for Education
While numerous studies have attempted to synthesize knowledge in the field of outdoor therapies (e.g., Fernee et al., 2019; Gass et al., 2020; Harper & Dobud, 2021), none have explored the underlying perceptions and conceptual frameworks through which they are defined, justified, and implemented. By examining how the semantics of nature and YMH have evolved and shaped outdoor therapies, this review provides the critical distance needed to identify the discursive and ideological foundations upon which particular programs are built.
The findings lead us to recommend that researchers, practitioners, and policymakers remain especially vigilant in recognizing ideological continuities within existing literature and practices, and in explicitly accounting for them when designing or evaluating programs. This conceptual coherence can help to minimize ambiguity and therefore strengthen a program's theoretical and pedagogical foundations. This work invites educators, teachers, and trainers to revisit their pedagogical frameworks by questioning the implicit conceptions of nature that underpin them. This calls for greater precision in how the role of nature is conceptualized, articulated, and operationalized within outdoor therapies. More broadly, the semantic shifts observed in this review highlight the need for educational practices that adopt holistic and ecocentric orientations, which could, in turn, enrich environmental and nature-based education beyond the specific domain of outdoor therapies for YMH. Indeed, the vast majority of the scientific community acknowledges that environmental issues are of anthropogenic origin (Bonneuil & Fressoz, 2013; Cocks & Simpson, 2015; Latour, 2015). From this perspective, we can only encourage the ongoing development of an ecocentric vision in programs, which necessarily implies a holistic approach encompassing both human and non-human dimensions.
Future Research
An important step in addressing the problems identified in this review could be to develop an analytical tool that allows program managers and facilitators to easily identify practices consistent with their theoretical orientation, and then incorporate these into their programs. Such a tool could help prevent a return to masculine and anthropocentric ways of thinking inherited from the earliest period of outdoor therapies, which would be highly detrimental to advancing a holistic and ecocentric approach in academic discourses and in practice (Cocks & Simpson, 2015). Researchers can contribute by designing and rigorously evaluating programs whose epistemological foundations are explicitly ecocentric and inclusive. Documenting and disseminating such examples would provide concrete models for practitioners, thereby fostering coherence between theoretical frameworks and practical implementation.
Footnotes
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Notes
Author Biographies
Appendix A
JBI Critical Appraisal Checklist (Lockwood et al., 2015, p. 184)
Appendix B
Evolution of factor representation
Appendix C