A Two-Factor Model Better Explains Heterogeneity in Negative Symptoms: Evidence from the Positive and Negative Syndrome Scale.

Seon-Kyeong Jang,Kee-Hong Choi,Young Il Cho,Soohyun Park,Ga-Young Lee,Hye-Im Choi,Eunju Jaekal

doi:10.3389/fpsyg.2016.00707

Seon-Kyeong Jang, Kee-Hong Choi + Show 5 more

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https://doi.org/10.3389/fpsyg.2016.00707

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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.

Highlights

Negative symptoms are an important dimension of schizophrenia symptoms, and are independent of positive and disorganized symptoms; negative symptoms have under-known pathological mechanisms and few treatment options (Harvey et al, 2006; Marder et al, 2011)
We aimed to examine the factor structure of the negative symptoms factor (NSF) in Korean individuals with chronic schizophrenia by comparing the fitness of the two-factor and single-factor models
The Korean version of the Brief Negative Symptom Scale (BNSS) showed good internal consistency (α = 0.94) and the two-factor structure of the original study exhibited adequate data fit: χ2 = 77.41, df = 49 (p < 0.01), normed chi-square (NC) = 1.58, CFI = 0.96, TLI = 0.95, RMSEA = 0.086 [CI: 0.047–0.121, 90%], and SRMR = 0.056

Summary

Introduction

Negative symptoms are an important dimension of schizophrenia symptoms, and are independent of positive and disorganized symptoms; negative symptoms have under-known pathological mechanisms and few treatment options (Harvey et al, 2006; Marder et al, 2011). Avolition (lack of interest in daily activities), asociality (reduced social interest and social withdrawal), and anhedonia (reduced ability to experience or anticipate pleasure) comprise the experiential deficits of negative symptoms, which may be correlated with, but are distinct from, expressive deficits such as blunted affect (diminished facial expression) and alogia (poverty of speech; Kirkpatrick et al, 2006) This two-factor structure has been verified in the course of the development of new assessments of negative symptoms and is reflected in the renewed conceptualization of negative symptoms in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (Messinger et al, 2011; Strauss et al, 2012; Kring et al, 2013)

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