Table 2.

Groups of definitions and approaches with relative description and references.

Definition groups	Description	References
Dysfunction-requiring definitions	We included here the authors who considered the concept of “dysfunction” to be the essential part of mental disorder and made it a conditio sine qua non. Note that the authors eventually conceptualized dysfunction itself in different ways.	Boorse (1977), Klein (1978), Boorse (1997), Matthewson and Griffiths (2017), Nielsen and Ward (2020)
Distress or disability-requiring definitions	We included here the authors who considered the negative consequences on adaptation as well as individual discomfort, as the central features of mental disorder, rather than dysfunction.	Woodruff et al. (1974), Ossorio (1985), Widiger and Trull (1991), Widiger (1997), Bergner (1997), Megone (1998), Bergner and Bunford (2017), Gala and Laughon (2017), Troisi (2015), Telles-Correia et al. (2018), Gauld (2022)
Dysfunction and distress or disability-requiring definitions	We included here the papers who argued mental disorder to require both a dysfunction and negative consequences such as distress and/or functional impairment.	Spitzer and Endicott (1978); Wakefield (1992a,b, 1999a, 2001, 2003, 2006, 2007, 2014, 2020), First and Wakefield (2010); Wakefield and First (2013), Wakefield and Conrad (2020); Stein et al. (2010, 2021)
Statistics-based definitions	We included here the definitions that discussed the concept of mental disorder referring to “levels of functioning” and to distributions of functioning, in which certain cut offs determine the line between pathology and non-pathology.	Cohen (1943), Scadding (1967), Kendell (1975), Boorse (1977), Boorse (1997)
Roschian concept approaches	We included in this group all the considerations made by authors who argued mental disorder to be a prototype concept.	Frances et al. (1990), Lilienfeld and Marino (1995), Gala and Laughon (2017), Gauld (2022)
Integrations between definitions and add-ons	We included here the authors who proposed some kind of integration between more definitions and/or proposed add-ons to previous definitions.	Schwartz, (2007a, 2017) and Malón (2012)
Critical approaches to mental disorder definition	We included here the authors who skeptically discussed the concept of mental disorder and/or argued mental disorder to be a value-laden and culturally driven concept.	Szasz (1960, 1974, 1994), Goffman (1968), Crowe (2000), Cooper (2002), Jacobs (2013), Horwitz (2017)