title: Measurement non-invariance of DSM-IV narcissistic personality disorder criteria across age and sex in a population-based sample of Norwegian twins.
abstract: We investigated measurement non-invariance of DSM-IV narcissistic personality disorder (NPD) criteria across age and sex in a population-based cohort sample of 2794 Norwegian twins. Age had a statistically significant effect on the factor mean for NPD. Sex had a statistically significant effect on the factor mean and variance. Controlling for these factor level effects, item-level analysis indicated that the criteria were functioning differently across age and sex. After correcting for measurement differences at the item level, the latent factor mean effect for age was no longer statistically significant. The mean difference for sex remained statistically significant after correcting for item threshold effects. The results indicate that DSM-IV NPD criteria perform differently in males and females and across age. Differences in diagnostic rates across groups may not be valid without correcting for measurement non-invariance.
authors.affiliation: Department of Psychiatry, Virginia Commonwealth University, P.O. Box 980126, Richmond, VA 23298-0126, USA. tkubarych@gmail.com
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Kubarych
authors.forename: Steven H
authors.initials: SH
authors.lastname: Aggen
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Kendler
authors.forename: Sven
authors.initials: S
authors.lastname: Torgersen
authors.forename: Ted
authors.initials: T
authors.lastname: Reichborn-Kjennerud
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
mesh_terms: D000328:Adult; D017677:Age Distribution; D018672:Community Health Planning; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D010552:Personality Assessment / Q000706:statistics & numerical data; D010554:Personality Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D012189:Retrospective Studies; D017678:Sex Distribution; D055815:Young Adult