title: A Two-Factor Model Better Explains Heterogeneity in Negative Symptoms: Evidence from the Positive and Negative Syndrome Scale.
abstract: Acknowledging separable factors underlying negative symptoms may lead to better understanding and treatment of negative symptoms in individuals with schizophrenia. The current study aimed to test whether the negative symptoms factor (NSF) of the Positive and Negative Syndrome Scale (PANSS) would be better represented by expressive and experiential deficit factors, rather than by a single factor model, using confirmatory factor analysis (CFA). Two hundred and twenty individuals with schizophrenia spectrum disorders completed the PANSS; subsamples additionally completed the Brief Negative Symptom Scale (BNSS) and the Motivation and Pleasure Scale-Self-Report (MAP-SR). CFA results indicated that the two-factor model fit the data better than the one-factor model; however, latent variables were closely correlated. The two-factor model's fit was significantly improved by accounting for correlated residuals between N2 (emotional withdrawal) and N6 (lack of spontaneity and flow of conversation), and between N4 (passive social withdrawal) and G16 (active social avoidance), possibly reflecting common method variance. The two NSF factors exhibited differential patterns of correlation with subdomains of the BNSS and MAP-SR. These results suggest that the PANSS NSF would be better represented by a two-factor model than by a single-factor one, and support the two-factor model's adequate criterion-related validity. Common method variance among several items may be a potential source of measurement error under a two-factor model of the PANSS NSF.
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Seon-Kyeong
authors.initials: SK
authors.lastname: Jang
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Hye-Im
authors.initials: HI
authors.lastname: Choi
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Soohyun
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Eunju
authors.initials: E
authors.lastname: Jaekal
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Ga-Young
authors.initials: GY
authors.lastname: Lee
authors.affiliation: Department of Psychology, Sungshin Women's University Seoul, South Korea.
authors.forename: Young Il
authors.initials: YI
authors.lastname: Cho
authors.affiliation: Department of Psychology, Korea University Seoul, South Korea.
authors.forename: Kee-Hong
authors.initials: KH
authors.lastname: Choi
keywords: experiential deficit; expressive deficits; negative symptoms; psychosis; schizophrenia; subdomain