Of Dodo birds and common factors: A scoping review of direct comparison trials in adventure therapy Will W. Dobud a, * , Nevin J. Harper b a Charles Sturt University, Australia b University of Victoria, Canada article info Article history: Received 26 October 2017 Received in revised form 16 December 2017 Accepted 18 January 2018 Keywords: Adventure therapy Wilderness therapy Common factors Scoping review abstract Background: Adventure therapy (AT) is a term that includes therapies such as wilderness therapy and adventure-based counseling. With growing empirical support for AT, the diversity of studies make it difficult to attribute outcomes to specific treatment factors. Objectives: Researchers explored whether AT, often perceived as an alternative therapy, works because of AT's unique components, or whether factors shared by all therapies were responsible. Methods: A scoping review was undertaken utilizing a search of major databases, unpublished disser- tations, and a hand search for direct comparison trials matching AT with another therapeutic intervention. Results: 881 publications were identified. 105 quantitative studies were included following a title and abstract review. Only 13 met the full inclusion criteria. Little to no differences were found to isolate specific therapeutic factors. Conclusions: We discuss the implications of these results considering the movement toward evidence- based practice and recommend future research to eclipse our current understanding of AT. © 2018 Elsevier Ltd. All rights reserved. 1. Introduction In 1936, friend and classmate of B. F. Skinner, psychologist Saul Rosenzweig, published Some Implicit Common Factors in Diverse Methods of Psychotherapy, in which he cited Lewis Carroll's [1] Ali- ce's Adventures in Wonderland. In Carroll's story, Alice's tears had drenched the animals and a race was held for the animals to dry themselves. At the end, the Dodo bird was asked who had won, and he declared, “Everybody has won, and all must have prizes” [p. 412, emphasis in original]. In his short paper, Rosenzweig [2] asked, if all the different models of therapy were equally effective for a diverse range of clients, then was each model of psychotherapy a winner as well? The Dodo's verdict was revisited by psychiatrist Jerome Frank [3] in 1961 and confirmed 30 years later that “despite decades of effort, no one has shown convincingly that one therapeutic model is more effective than any other for the majority of psychological illnesses” and suggested that “the specific effects of particular healing methods may be overshadowed by therapeutically potent ingredients shared by all” [3, p. 2]. Referred to as the ‘common factors,’ these include a relationship between a therapist and client, a therapeutic rationale for delivering the service, and placebo or expectancy [4,5]. Empirical support for these factors exists [6e9] as they make up the largest variance found in outcome studies when specific treatment approaches are compared. Despite the work of Rosenzweig [2] and Frank and colleagues [3, 10, 11] and meta-analytic evidence supporting the Dodo's verdict [4, 12e15], specific techniques dominate mental health literature, informing both policy and reimbursement [16, 17]. Over the last half a century, more empirically supported treatments and more mental disorders have been catalogued [5] with no improvement in out- comes since therapy's first meta-analysis [7 , 12, 14]. The Dodo's claim that all models are deserving of prizes points to the robust- ness of outcomes across all models rather than the specifics of what works best and for whom [18]. Within adventure therapy (AT), debate exists about how it works and whether there are some specific ingredient(s) unique to AT's effectiveness [19e21]. Harper, Peeters, and Carpenter [22] suggested AT is an umbrella term encompassing a multitude of related approaches described in the literature, such as wilderness therapy, outdoor behavioral healthcare, bush adventure therapy, * Corresponding author. 2 Kintore Ave, Hazelwood Park, SA 5066, Australia. E-mail address: wdobud@csu.edu.au (W.W. Dobud). Contents lists available at ScienceDirect Complementary Therapies in Clinical Practice journal homepage: www.elsevier.com/locate/ctcp https://doi.org/10.1016/j.ctcp.2018.01.005 1744-3881/© 2018 Elsevier Ltd. All rights reserved. Complementary Therapies in Clinical Practice 31 (2018) 16e24