The Structure of Negative Symptoms Within Schizophrenia: Implications for Assessment

Abstract

This review examines the structural validity of negative symptoms focusing on 2 questions: (1) Do negative symptoms represent a domain separate from other symptoms in schizophrenia? and (2) Within negative symptoms, is there a structure that suggests multidimensionality? Results from exploratory and confirmatory factor analytic studies are examined to address these questions. Across studies and symptom instruments, negative symptoms appear to consistently emerge as a factor separate from other dimensions of the illness in schizophrenia. Whether 2-, 3-, or 5-factor models are identified, negative symptoms consistently load on a factor separate from positive symptoms, affective symptoms of depression or anxiety, and symptoms of disorganization. Focusing on negative symptoms themselves, factor analytic findings suggest that this construct is multidimensional with at least 2 factors (involving diminished expression and anhedonia-asociality). Although these factors were replicable, serious limitations were noted in this literature. Thus, 2- (or even 3- or 5-) factor models of negative symptoms should not be considered definitive, but rather all converge to support the general conclusion of the multidimensionality of negative symptoms. The later findings indicate the importance of employing assessments that provide adequate coverage of the broad domain of negative symptoms. Importantly, caution is noted in the interpretability of findings based on existing instruments, and implications for future assessment are discussed.

The relationship between experiential deficits of negative symptoms and subjective quality of life in schizophrenia

“…These findings support the argument that experiential and expressive symptoms represent distinct subdomains (Blanchard and Cohen, 2006), and as such should be measured separately . Assessing the symptoms in this manner may better resemble the negative symptom construct as it is currently understood, and may yield new insights which have previously been undetected.…”

Loss of erbB signaling in oligodendrocytes alters myelin and dopaminergic function, a potential mechanism for neuropsychiatric disorders

“…Our results suggest that defects in erbB signaling in OLs may contribute to positive and negative symptoms of this disease. Reduced locomotion and social dysfunction observed in CNP-DNerbB4 are reminiscent of negative symptoms of chronic schizophrenia patients who exhibit motor retardation and social withdrawal (40). Approximately 40% of schizophrenia patients have increased sensitivity to amphetamine during an acute schizophrenic episode.…”

Randomized Controlled Trial of Cognitive Behavioral Social Skills Training for Older Consumers With Schizophrenia: Defeatist Performance Attitudes and Functional Outcome

“…The Positive and Negative Syndrome Scale (PANSS) (26), Scale for the Assessment of Negative Symptoms (SANS) (27), Beck Depression Inventory – 2 nd Edition (BDI-II) (28), and Beck Anxiety Inventory (BAI) (29) were administered to assess clinical symptoms. Based on factor analytic studies of the SANS (30–32), two negative symptom factors were derived: Diminished Expression , defined as the average of Affective Flattening and Alogia global ratings (items 8, 13); and Diminished Motivation , defined as the average of Avolition-Apathy and Anhedonia-Asociality global ratings (items 17, 22). The Self-Esteem Rating Scale-Short Form (SERS) 33) is a 20-item self-report scale.…”