TABLE 1.

Developmental factors in the etiology of narcissistic personality disorder

Factor	Grandiose narcissism	Vulnerable narcissism	Studies
Childhood adversity	Emotional abuse		Clemens et al., 2022 (54)
	Physical abuse	Physical abuse	Cohen et al., 2014 (55): Keene and Epps, 2016 (56)
	Physical neglect		Hengartner et al., 2013 (57)
	Verbal abuse		Johnson et al., 2001 (58)
	Parental hostility		Wetzel and Robins, 2016 (59)
	Maltreatment	Maltreatment	Bertele et al, 2022 (60)
Parenting styles	Parental overvaluation		Brummelman et al., 2015 (61)
	Paternal lenient discipline and overvaluation	Maternal lenient discipline; permissiveness, overindulgence	Van Schie, 2020 (62)
	Invalidation	Invalidation	Huxley and Bizumic, 2017 (63)
	Lack of warmth; coldness, rejection	Coldness, rejection	Horton et al., 2006 (64); Otway and Vignoles, 2006 (65); Watson et al., 1995 (66); for opposite findings, see Horton and Tritch, 2014 (67)
	Parental control		Horton et al., 2006 (64); Horton and Tritch, 2014 (67); Winner and Nicholson, 2018 (68)
	Overprotection	Overprotection	Brummelman et al., 2015 (61), Winner and Nicholson, 2018 (68); Segrin et al., 2013 (69); Segrin et al., 2012 (70)
Attachment style	Dismissive		Diamond et al., 2014 (46)
	Avoidant		Diamond et al., 2014 (46)
	Not possible to classify		Diamond et al., 2014 (46)
		Preoccupied	Cramer, 2019 (47)
		Fearful	Cramer, 2019 (47)