Taxometric Analysis of Negative Symptoms in An International Sample of Ten Countries
Blanchard, Jack J
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Negative symptoms have emerged as a replicable factor of symptomatology within schizophrenia. Although rating scales provide assessments along dimensions of severity, categorization of a negative symptom subtype is typically concluded. Despite an accumulation of findings that support categorical conceptualization, the data are also consistent with a dimensional-only model where negative symptom subtypologies simply reflect an extreme on a continuum of severity. Previous studies (Blanchard, et al, 2005) have used taxometric statistical methods to confirm the existence of a negative symptom subtype; however, the nature of taxometric methods requires replication (Waller & Meehl, 1998). The current investigation is a taxometric analysis of the World Health Organization Ten-Country Study of Schizophrenia. Data from a subset of 694 individuals were analyzed using the taxometric methods of maximum covariance analysis (MAXCOV) and mean above minus below a cut (MAMBAC) and a latent class with a base rate of approximately .14 - .16 was identified.