Table 2.

Differential item functioning (DIF) of DSM-IV Narcissistic Personality Disorder (NPD) symptoms by sex in the full NESARC sample.

DSM-IV symptoms	Females (N=19975)				Males (N=14501)				DIFFTEST a			DIFFTEST b
	a	Rank a	b	Rank b	a	Rank a	b	Rank b	X2Difference	pDifference	DIFa	X2Difference	pDifference	DIFb
Grandiose sense of self-importance	0.96	2	2.40	3	1.08	2	2.53	5	3.9	0.049	−0.12	34.5	<0.001	−0.12
Preoccupied with fantasies	1.25	5	2.98	8	1.22	3	3.01	8	0.1	0.705	0.02	0.0	0.850	−0.03
Believes he/she is special/unique	0.96	1	2.98	7	0.96	1	2.94	7	0.2	0.625	0.00	0.8	0.369	0.04
Requires excessive admiration	1.32	7	2.65	6	1.49	9	2.65	6	2.7	0.098	−0.17	4.7	0.030	0.00
Sense of entitlement	1.44	9	2.13	1	1.45	8	1.98	2	1.1	0.296	−0.01	17.6	<0.001	0.16
Interpersonally exploitative	1.36	8	2.52	5	1.42	7	2.41	3	1.0	0.309	−0.06	3.1	0.079	0.12
Lack of empathy	1.22	4	2.17	2	1.25	5	1.88	1	1.3	0.250	−0.03	58.2	<0.001	0.29
Being envious	1.06	3	2.41	4	1.34	6	2.47	4	8.6	0.003	−0.28	50.7	<0.001	−0.07
Arrogant/haughty behaviors/attitudes	1.28	6	3.02	9	1.23	4	3.20	9	0.0	0.847	0.05	4.6	0.032	−0.18

Note: a = discrimination parameter estimate, b = severity parameter estimate.

p-values were adjusted for multiple testing using the Benjamini-Hochberg procedure.

Values for chi square tests in bold are statistically (p<0.05) and clinically (DIF>0.25) significant.

Sampling weights and design effects of the NESARC were taken into account.

DIFFTEST a = comparing both models with the factor loading respectively free and fixed for the corresponding item.

DIFFTEST b = comparing both models with the threshold respectively free and fixed for the corresponding item.