The term mental illness is defined as “a clinically diagnosable disorder that significantly interferes with an individual's cognitive, emotional or social abilities”.1(p.44) Mental illness is used generally as a term to describe a number of different types of mental illness, or disorders, and with differing severity.2 The worldwide burden of mental illness is significant, with mental, neurological and substance use disorders accounting for 13% of the total global burden of disease in 2004.3 Depression and anxiety, the two most common mental illnesses, are becoming more prevalent throughout the world.4 Depression accounts for 4.3% of the global burden of disease, with an increase of 18.4% over a 10-year period, and is ranked as the single largest contributor of disability worldwide.5 These epidemiological figures serve to highlight the extent and far-reaching impact that mental illness has on diagnosed individuals and the community. The diagnosis of a mental illness is generally made by clinicians according to the classification systems of the Diagnostic and Statistical Manual of Mental Disorders or the International Classification of Diseases.1 Clinical care and treatments are predominately pharmacological, specific to the diagnosis and aimed at reducing the severity of symptoms.1
Yet, mental health recovery is regarded as a highly subjective and personal concept which incorporates broader aspects of health and wellness.1,6 The notion of mental health recovery was instigated by, and for, persons with a mental illness to describe their own experiences and to support their self-identity beyond the limits of a diagnosis.7 Hence, mental health services aim to provide a range of diverse and person-centered initiatives that support persons living with a mental illness to achieve their realization of their own mental health recovery.8 Through consultation with persons who have lived experiences of mental illness, mental health services are using more positive language to describe people who access their services. Terms such as “consumer”, “client” or “service user” are used to reflect the more holistic recovery-focused approach being taken.7 Included within this holistic approach, there are reported benefits of mental health services using recreation as a therapy to improve social, physical and mental health.9-11 It is widely accepted that recreation can enrich or enhance mental health, because the manner in which people occupy themselves in their free time can have a positive or negative impact on their health and wellbeing.12 Consequently, the therapeutic use of recreation to benefit persons with a mental illness is emerging as an alternative adjunct to the more traditional forms of clinical mental health care.13
Therapeutic recreation (TR) is considered as a health care approach which delivers recovery-oriented care as well as reduces the disabling effect of mental illness.12,14,15 According to the American Therapeutic Recreation Association16 the aim of TR is to optimize health and improve quality of life through meaningful participation in recreational activities. As a therapy, TR is structured so that it may use the benefits of recreation activities to “remediate and rehabilitate a person's level of functioning and independence.”16(para.2) Current published studies demonstrate that TR promotes person-centeredness, holistic health and wellbeing by using activities which enhance physical, mental and social engagement.17-19 Different population groups, including people with disabilities and/or mental illness, are reported to find participation in TR beneficial.20-23 Examples of TR activities include walking groups, swimming groups, soccer, horse-riding groups, art and craft activities, and theater groups and can occur in both indoor and outdoor settings.24 There are reported benefits of undertaking recreation in outdoor nature-based settings. It is claimed that there are three ways in which exposure to nature can positively influence mental health and wellbeing.25-29 Firstly, participation in physical activity in a nature-based setting can enhance positive mood and lessen psychological distress levels.26,30-32 Secondly, mental wellbeing is improved through increased opportunities for organized and spontaneous social engagement.27,33,34 Thirdly, nature-based settings can provide restoration from stressful activities25,26,29 and positively affect stress hormone levels.35
Leisure activities are widely perceived as pleasurable activities freely chosen by a person and are often spontaneous, self-directed and can be undertaken singularly or in groups.12 Therapeutic recreation is regarded as a more structured form of leisure which is designed by healthcare services to intentionally offer health benefits to people with long-term health conditions.16 Hood and Carruthers17 identified components of TR which enhance well-being while simultaneously overcoming barriers that inhibit mental health recovery. The identified components are increasing physical activity; increasing cognitive abilities; savoring positive emotions; increasing social and spiritual connections; developing mindfulness skills and engaging in altruism.17 Hood and Carruthers17 claim TR is essentially a strengths-based intervention with activities designed to utilize the person's intrinsic resources and build their capacity, rather than focusing on their problems or disability. Hence, TR activities are often designed to focus on the person's internal locus of control and facilitate goal setting, self-determination and autonomy.11,18,36,37
In addition to the positive benefits, evidence shows that as a result of participating in outdoor-based TR, a person is able to develop a perceived sense of self-control, mastery and competency.9,13,18 Similar findings relating to improvements in mastery, connectedness, self-esteem, mental health, general medical health, wellbeing, confidence, teamwork and trust, and communication and interaction with others were identified in an outdoor nature-based Australian study undertaken with 108 young people and adults with a mental illness.9
Participation in TR in an outdoor setting can enhance social connectedness as well as improve mental health and wellbeing.17,19,38,39 A study conducted by Mutz and Muller22 investigated the impact of an outdoor adventure camp on the mental health and wellbeing of undergraduate university students. The results revealed a measurable increase in life satisfaction, happiness, mindfulness and self-efficacy and a decrease in perceived stress in the participants.22
A benefit of undertaking TR in nature-based settings is that it acts as a buffer to life's stresses, enhances resilience and aids in overcoming past negative life experiences.17,18,40,41 Taylor et al.36 claim that people living with a mental illness often experience daily barriers inhibiting mental health, so the benefit of developing strategies to overcome negative life experiences is pertinent.
Corring et al.42 explored the benefits of horse-riding as a form of TR for people living with schizophrenia or schizoaffective disorder. The study's participants described experiencing a sense of increased enjoyment, self-esteem and self-confidence resulting from increasing their horsemanship skills.42 Often, people experiencing long-term mental distress, or the negative symptoms of schizophrenia, such as amotivation, have fewer positive experiences to draw upon, and therefore these reported benefits should not be underestimated.42 Another benefit reported was that the mental health staff developed more favorable perceptions towards the participants after witnessing positive changes in the participants.42 As a result of this finding, the authors suggest TR as a way of instilling optimism within the mental health care profession.
Therapeutic recreation is predominately practiced as a therapy in America and Canada, while it is still emerging as a therapy internationally.14 Evidence demonstrating the efficacy and effectiveness of outdoor-based TR as a mental health care approach has gained momentum in the last five years within Australia, and is largely associated with a project known as Recovery Camp.11,13,14,19,36,43,44 Recovery Camp is an immersive outdoor TR experience in the form of an adventure camp which is undertaken over five days and four nights. Located in the Australian countryside in New South Wales, adults over 18 with a mental illness share cabin accommodation and participate in varied physical and recreation activities such as archery, orienteering, wall climbing, a 40-foot high (12 meters) flying fox, a 60-foot high (18 meters) giant swing, alpine rescue, yoga, art and a high wire course.11 Moxham et al.14 conducted a pilot study which examined the expectations of 27 participants with a mental illness of their TR experience at Recovery Camp. The findings showed that Recovery Camp was regarded as a gratifying experience and the participants’ expectations were met.14 Participants described taking advantage of the recreational opportunities and experiencing a sense of purpose while managing any stress arising from being out of their usual routines. Therapeutic recreation was perceived by participants to increase social inclusion and develop relationships, with 95% of participants reporting that the experience enabled them to meet new people.14 Other themes identified were improved sleep, healthier eating habits, experiencing positive emotions and becoming more relaxed. The authors suggested the TR delivered at Recovery Camp fostered personal mental health recovery.14 Another study conducted on Recovery Camp by Patterson et al.13 investigated whether TR enhanced the sense of control, or perceived control, among persons with a mental illness. The results demonstrated that TR can benefit personal mental health recovery through empowering people to gain a greater sense of control over their attitudes and decision making.13
Persons living with a mental illness can have limited choices when accessing community-based mental health services that aim to foster mental health recovery.45 The emergence of outdoor TR in Australia highlights how mental health services are diversifying to facilitate personal mental health recovery for adults residing in community settings. Additionally, mental health services are placing greater importance on qualitative evidence to provide insight into what it means for people accessing their service to inform service delivery.45 Despite the reported benefits from the existing literature of TR in outdoor nature-based settings, the qualitative findings from the perspective of persons with a mental illness have not been synthesized in a manner that will enable the development of evidence-based recommendations relating specifically to the use of outdoor TR, to promote mental health recovery. An initial search was conducted in December 2018 of the JBI Database of Systematic Reviews and Implementation Reports, Cochrane Library, MEDLINE, and CINAHL databases, as well as the PROSPERO register. One integrative literature review was identified. The integrative review by Fenton et al.24 had synthesized the findings of 35 qualitative and quantitative papers of diverse methodologies to examine the benefits, barriers, and facilitators to participation in community-based recreation for persons with a mental illness. The integrative review reported the top quarter of the studies revealed that recovery is supported through increased self-esteem and self-confidence, and the expansion of social networks and feelings of social inclusion.24 These findings support the value of engagement in community-based TR to support recovery. Although the focus of integrative review was on the social aspects of community-based recreation, the two types of included studies involved physical and creative activities which were held both indoors and outdoors. Additionally, the authors acknowledged that the focus of the integrative review was on the physical health benefits associated with exercise and physical activity in people with mental health issues and included publications up to 2014 only.24 Hence, this systematic review differs from Fenton et al.24 by specifically focusing on outdoor TR activities located in nature-based settings and including publications up to 2018. The rationale of conducting a synthesis of the qualitative evidence is to clarify the meaning of outdoor TR through perspectives of people living with a mental illness. In doing so, the qualitative methodological approach of research which explores the individuals’ experience will inform mental health service delivery of the consumer's perspective.46 Therefore, this meta-aggregation will provide a current synthesis with graded levels of evidence of the meaning of outdoor-based TR among persons with mental illnesses and inform future TR initiatives both in Australia and internationally.
The objective of the review is to identify, appraise and synthesize the best available evidence related to participation in outdoor therapeutic recreation programs for adults with a mental illness living in the community.
What are the experiences of adults with a mental illness living in the community relating to participation in outdoor therapeutic recreation programs?
The review will consider studies that include adults who are aged 18 years or over, live in the community and have a diagnosis of a mental illness or have been referred to the intervention by mental health services.
Phenomena of interest
Studies will be included if they have explored the subjective experiences of outdoor TR programs of the participants. The type of programs, services or initiatives offering outdoor recreation activities include adventure camps; TR; sporting, gardening, and community-based leisure programs and healthy lifestyle programs which are primarily focused on the use of recreation to enhance mental health recovery.
Excluded programs include services or initiatives which are primarily focused on exercise, fitness or physical activity with the aim to enhance solely physiological outcomes such as weight loss, power, flexibility or physical behavior changes.
Studies will be included when based outdoors in community settings.
Types of studies
This review will consider studies that focus on qualitative data including, but not limited to, designs such as phenomenology, grounded theory, ethnography, qualitative description, action research and feminist research. Studies published in English will be included. There will be no date limitation on studies.
The search strategy will aim to find both published and unpublished studies. A three-step search strategy will be implemented in this review. An initial limited search of MEDLINE and PsycINFO will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe articles. A second search using all identified keywords and index terms will then be undertaken across all included databases. Thirdly, the reference lists of all identified reports and articles will be searched for additional studies. Studies published in English will be considered for inclusion in this review. Authors of primary studies will be contacted for missing information or to clarify any unclear data. A full search strategy for PsycINFO is detailed in Appendix I. The reference lists of all studies selected for critical appraisal will be screened for additional studies. Therapeutic recreation journals and occupational therapy journals will also be searched for relevant studies.
The databases to be searched include: MEDLINE, CINAHL, PsycINFO, Scopus and Informit. The search for unpublished studies will include: Google Scholar and gray literature databases.
Following the search, all identified citations will be collated and uploaded into Endnote V.17 (Clarivate, PA, USA) and duplicates removed. Titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria for the review. Studies that may meet the inclusion criteria will be retrieved in full and their details imported into JBI System for the Unified Management, Assessment and Review of Information (JBI SUMARI; JBI, Adelaide, Australia). The full text of selected studies will be retrieved and assessed in detail against the inclusion criteria. Full text studies that do not meet the inclusion criteria will be excluded and reasons for exclusion will be provided in an appendix in the final systematic review report. Included studies will undergo a process of critical appraisal. The results of the search will be reported in full in the final report and presented in a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)49 flow diagram. Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer.
Assessment of methodological quality
Selected studies will be critically appraised by two independent reviewers at the study level for methodological quality in the review using the JBI Critical Appraisal Checklist for Qualitative Research.47,48,50 Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer. The results of critical appraisal will be reported in narrative form and in a table.
Qualitative data will be extracted from papers included in the review using the standardized data extraction tool as described in the JBI Reviewer's Manual48 by one reviewer and checked by the second reviewer. The data extracted will include specific details about the populations, context, culture, geographical location, study methods and the phenomena of interest relevant to the review question and specific objectives. Findings, and their illustrations, will be extracted and assigned a level of credibility.
Qualitative research findings will, where possible, be pooled using the meta-aggregation approach.47 This will involve the aggregation or synthesis of findings to generate a set of statements that represent that aggregation, through assembling the findings and categorizing these findings on the basis of similarity in meaning. These categories are then subjected to a synthesis in order to produce a single comprehensive set of synthesized findings that can be used as a basis for evidence-based practice. Where textual pooling is not possible, the findings will be presented in narrative form.
Assessing confidence in the findings
The final synthesized findings will be graded according to the ConQual approach for establishing confidence in the output of qualitative research synthesis and presented in a Summary of Findings.50 The Summary of Findings includes the major elements of the review and details how the ConQual score is developed. Included in the table is the title, population, phenomena of interest and context for the specific review. Each synthesized finding from the review is then presented along with the type of research informing it, a score for dependability, credibility and the overall ConQual score.48,50
The reviewers wish to acknowledge Rachel Jones, Librarian at the University of Wollongong, for her guidance with formulating search strategies.
Appendix I: Search strategy for PsycINFO
- mental illness.mp. or exp Mental Disorders/
- mental health.mp. or exp Mental Health/
- psychiatric disorder.mp.
- exp Mental Health/ or exp Mental Disorders/ or mental wellness.mp.
- exp Recreation Areas/ or exp Recreation/ or exp Leisure Time/ or exp Physical Activity/ or outdoor recreation.mp.
- exp Recreation Therapy/ or exp Recreation/ or exp Leisure Time/ or therapeutic recreation.mp.
- recreation therapy.mp. or exp Recreation Therapy/
- recreational therapy.mp.
- leisure therapy.mp.
- exp Therapeutic Camps/ or exp Adventure Therapy/ or adventure camp.mp. or exp Wilderness Experience/
- exp LEISURE TIME/ or leisure.mp.
- adventure therapy.mp. or exp Adventure Therapy/
- outdoor recreation.mp.
- sports.mp. or exp SPORTS/
- 1 or 2 or 3 or 4
- 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15
- 16 and 17
- exp QUALITATIVE RESEARCH/ or qualitative.mp.
- 18 and 19
- limit 20 to (human and english language and “300 adulthood ”)
1. Commonwealth of Australia. The roadmap for national mental health reform 2012–2022. Canberra: Council of Australian Governments; 2012.
2. American Psychiatric Association. Diagnostic and Statistical Manual of mental disorders. 5 ed.Washington DC: APA Press; 2013.
3. World Health Organization. Global burden of mental disorders and the need for a comprehensive, coordinated response from health and social sectors at the country level. Geneva: World Health Organization; 2011.
4. Australian Bureau of Statistics. National Health Survey: first results 2014–2015 Canberra, ABS Catalogue No. 4364.0.55.001: Commonwealth of Australia; 2015.
5. World Health Organization. Depression and other common mental disorders: global health estimates. Geneva: World Health Organization; 2017.
6. Slade M, Longdon E. The empirical evidence about mental health and recovery
, how likely, how long, what helps!. Victoria: MI Fellowship; 2015.
7. Commonwealth of Australia. A national framework for recovery
-oriented mental health services: a guide for practitioners and providers. Australian Health Ministers Advisory Council 2013.
8. Smith PS, Williams TM. From providing a service to being of service: advances in person-centred care in mental health. Curr Opin Psychiatry
2016; 29 (5):292–297.
9. Cotton S, Butselaar F. Adventure camp for young adults and adults with mental illness. Psychiatr Serv
2012; 63 (11):1154.
10. Mason O, Holt R. Mental health and physical activity interventions: a review of qualitative
literature. J Ment Health
2012; 21 (3):274–284.
11. Picton C, Patterson C, Moxham L, Taylor EK, Perlman D, Brighton R, et al. Empowerment: The experience of Recovery
Camp for people living with a mental illness. Collegian
2017; 25 (1):113–118.
12. Iwasaki Y, Coyle C, Shank J, Messina E, Porter M, Salzer H, et al. Role of leisure in recovery
from mental illness. Am J Psychiatr Rehabil
2014; 17 (2):147–165.
13. Patterson C, Moxham L, Taylor E, Perlman D, Brighton R, Hefferman T, et al. Perceived control among people with severe mental illness: a comparative study. Arch Psychiatr Nurs
2016; 30 (5):563–567.
14. Moxham L, Liersch-Sumskis S, Taylor E, Patterson C, Brighton R. Preliminary outcomes of a pilot therapeutic recreation camp for people with a mental illness: links to recovery
. Ther Recreation J
2015; 49 (1):61–75.
15. Sylvester C. Therapeutic Recreation and disability studies: seeking an alliance. Ther Recreation J
2014; 48 (1):46–60.
16. American Therapeutic Recreation Association. FAQ about RT/TR 2018 [Internet]. [updated 21 September 2017; cited 31 July 2018]. Available from: https://www.atra-online.com/what/FAQ
17. Hood C, Carruthers C. Strengths-based TR program development using the leisure and well-being model. Ther Recreation J
2016; 50 (1):4–20.
18. Jennings C, Guerin S. Therapeutic recreation models of practice: a synthesis of key elements and examination of children's narratives of a camp experience for the evidence of these elements. Ther Recreation J
2014; 48 (4):303–319.
19. Picton C, Moxham L, Patterson C, Sumskis S, Brighton R, Perlman D, et al. Using therapeutic recreation as a means to increase physical activity and reduce social isolation. ACMHN's 42nd International Mental Health Nursing Conference Nurses Striving to Tackle Disparity in Health Care; 25–27 October 2016; Adelaide Convention Centre, Australia: Wiley online; 2016. p. 42.
20. Picton C. How therapeutic recreation contributes to recovery
for people living with mental illness. Int J Ment Health Nurs
2015; 24 (1):37–38.
21. Snethen G, McCormick B, van Puymbroeck M. Community involvement, planning and coping skills: pilot outcomes of a recreation intervention for adults with schizophrenia. Disabil Rehabil
2012; 34 (18):1575–1584.
22. Mutz M, Muller J. Mental health benefits of outdoor adventures: results from two pilot studies. J Adolesc
2016; 49 (1):105–114.
23. Stumbo N, Wilder A, Zahl M, DeVries D, Pegg S, Greenwood J, et al. Community integration: showcasing the evidence for therapeutic recreation services. Ther Recreation J
2015; 49 (1):35–60.
24. Fenton L, White C, Gallant KA, Gilbert R, Hutchinson S, Hamilton-Hinch B, et al. The benefits of recreation for the recovery
and social inclusion of individuals with mental illness: an integrative review. Leis Sci
2017; 39 (1):1–19.
25. Korpela K, Borodulin K, Neuvonen M, Paronen O, Tyrväinen L. Analyzing the mediators between nature-based outdoor recreation
and emotional well-being. J Environl Psychol
2014; 37 (1):1–7.
26. Nutsford D, Pearson AL, Kingham S. An ecological study investigating the association between access to urban green space and mental health. Public Health
2013; 127 (11):1005–1011.
27. Zhou X, Parves RM. Social benefits of urban green space: a conceptual framework of valuation and accessibility measurements. Manag Environ Qual Int J
2012; 23 (2):173–189.
28. Tzoulas K, Korpela K, Venn S, Yli-Pelkonen V, Kaźmierczak A, Niemela J, et al. Review: Promoting ecosystem and human health in urban areas using Green Infrastructure: a literature review. Lands Urban Plan
2007; 81 (3):167–178.
29. Kaplan S. The restorative benefits of nature: toward an integrative framework. J Environ Psychol
1995; 15 (3):169–182.
30. Astell-Burt T, Feng X, Kolt GS. Mental health benefits of neighbourhood green space are stronger among physically active adults in middle-to-older age: evidence from 260,061 Australians. Prev Med
2013; 57 (5):601–606.
31. Barton J, Osborne N, Pretty J, Barton J, Barton J, Pretty J. What is the best dose of nature and green exercise for improving mental health? A multi-study analysis. Environ Sci Tech
2010; 44 (10):3947–3955.
32. Gascon M, Triguero-Mas M, Martínez D, Dadvand P, Forns J, Plasència A, et al. Mental health benefits of long-term exposure to residential green and blue spaces: a systematic review. Int J Environ Res Public Health
2015; 12 (4):4354.
33. de Vries S, Verheij RA, Groenewegen PP, Spreeuwenberg P. Natural environments—healthy environments? An exploratory analysis of the relationship between greenspace and health. Environ Plann A
2003; 35 (10):1717–1731.
34. Dadvand P, Bartoll X, Basagaña X, Dalmau-Bueno A, Martinez D, Ambros A, et al. Green spaces and general health: roles of mental health status, social support, and physical activity. Environ Int
2016; 91 (1):161–167.
35. Ward Thompson C, Roe J, Aspinall P, Mitchell R, Clow A, Miller D. More green space is linked to less stress in deprived communities: evidence from salivary cortisol patterns. Landsc Urban Plan
2012; 105 (3):221–229.
36. Taylor E, Perlman D, Moxham L, Pegg S, Patterson C, Brighton R, et al. Recovery
Camp: assisting consumers toward enhanced self-determination. Int J Ment Health Nurs
2017; 26 (3):301–308.
37. Moxham L, Taylor EK, Patterson C, Perlman D, Brighton R, Heffernan T, et al. Goal setting among people living with mental illness: a qualitative
analysis of recovery
camp. Issues Ment Health Nurs
2017; 38 (5):420–424.
38. Alford S. What mentally-ill adults gain from participating in outdoor community outreach programs delivered by outdoors Inc. Hamburg: Hamburg University of Applied Sciences; 2014.
39. Allsop J, Negley S, Sibthorp J. Assessing the social effect of therapeutic recreation summer camp for adolescents with chronic illness. Ther Recreation J
2013; 47 (1):35–46.
40. Price W, Lundberg N, Zabriske R, Barney K. ’I tie flies in my sleep’: an autoethnographic examination of recreation and reintegration for a veteran with post-traumatic stress disorder. J Leis Res
2015; 47 (2):185–201.
41. Tsaur S, Lin W, Cheng T. Towards a structural model of challenge experience in adventure recreation. J Leis Res
2015; 47 (3):322–336.
42. Corring D, Lundberg E, Rudnick A. Therapeutic horseback riding for ACT patients with schizophrenia. Community Ment Health J
2013; 49 (1):121–126.
43. Cowley T, Sumskis S, Moxham L, Taylor E, Brighton R, Patterson C, et al. Evaluation of undergraduate nursing students’ clinical confidence following a mental health recovery
camp. Int J Ment Health Nurs
2016; 25 (1):33–41.
44. Moxham L, Taylor E, Patterson C, Perlman D, Brighton R, Sumskis S, et al. Can a clinical placement influence stigma? An analysis of measures of social distance. Nurse Educ Today
2016; 44 (1):170–174.
45. NSW Mental Health Commission. Living Well: putting people at the centre of mental health reform in NSW. Sydney 2014.
46. Earle V. Phenomenology as research method or substantive metaphysics? An overview of phenomenology's uses in nursing. Nurs Philos
2010; 11 (4):286–296.
47. Lockwood C, Munn Z, Porritt K. Qualitative
research synthesis: methodological guidance for systematic reviewers utilizing meta-aggregation. Int J Evid Based Healthc
2015; 13 (3):179–187.
48. Lockwood C, Porrit K, Munn Z, Rittenmeyer L, Salmond S, Bjerrum M, et al. Chapter 2: Systematic reviews of qualitative
evidence—data extraction. In: Aromataris E, Munn Z (eds). Joanna Briggs Institute Reviewer's Manual [Internet]. Adelaide: Joanna Briggs Institute. [updated 27 July 2017, cited 31 July 2018]. Available from: https://reviewersmanual.joannabriggs.org/
49. Moher D, Liberati A, Tetzlaff J, Altman DG. The PRISMA Group. Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med
2009; 6 (7):1000097.
50. Munn Z, Porritt K, Lockwood C, Aromataris E, Pearson A. Establishing confidence in the output of qualitative
research synthesis: the ConQual approach. BMC Med Res Methodol
2014; 14 (1):108.