Network Analysis Reveals the Latent Structure of Negative Symptoms in Schizophrenia

Abstract

Prior studies using exploratory factor analysis provide evidence that negative symptoms are best conceptualized as 2 dimensions reflecting diminished motivation and expression. However, the 2-dimensional model has yet to be evaluated using more complex mathematical techniques capable of testing structure. In the current study, network analysis was applied to evaluate the latent structure of negative symptoms using a community-detection algorithm. Two studies were conducted that included outpatients with schizophrenia (SZ; Study 1: n = 201; Study 2: n = 912) who were rated on the Brief Negative Symptom Scale (BNSS). In both studies, network analysis indicated that the 13 BNSS items divided into 6 negative symptom domains consisting of anhedonia, avolition, asociality, blunted affect, alogia, and lack of normal distress. Separation of these domains was statistically significant with reference to a null model of randomized networks. There has been a recent trend toward conceptualizing the latent structure of negative symptoms in relation to 2 distinct dimensions reflecting diminished expression and motivation. However, the current results obtained using network analysis suggest that the 2-dimensional conceptualization is not complex enough to capture the nature of the negative symptom construct. Similar to recent confirmatory factor analysis studies, network analysis revealed that the latent structure of negative symptom is best conceptualized in relation to the 5 domains identified in the 2005 National Institute of Mental Health consensus development conference (anhedonia, avolition, asociality, blunted affect, and alogia) and potentially a sixth domain consisting of lack of normal distress. Findings have implications for identifying pathophysiological mechanisms and targeted treatments.

<p>Pilot Validation Study of the Japanese Translation of the Brief Negative Symptoms Scale (BNSS)</p>

“…Although the items in Anhedonia, Avolition, and Asociality subscales loaded to the same factor in a previous factor analysis in BNSS 9,18,24,26,27 and CAINS, 13 recent studies revealed that five or more factor models fit better than two-factor models in BNSS and CAINS. 28,[33][34][35] This is in line with the following idea in the original NIMH report: "The five domains may have separate neurobiological substrates and may represent separate therapeutic targets." 5 Some of the neurobiological tasks exploring the biological basis specific to the each of the five domains have been adopted in clinical studies.…”

The Fragile Brain: Stress Vulnerability, Negative Affect and GABAergic Neurocircuits in Psychosis

“…[65][66][67] A recent categorial formulation distinguished a distress subtype, distinct from the deficit (enduring negative symptom) subtype in chronic schizophrenia patients, 81 and a network analysis of negative symptoms found an inverse relationship with NA. 82 Using continuous measures, others have found higher negative symptoms associated with reduced NA 29,83 and less reactivity to negative stimuli, 84,85 raising the intriguing possibility that affective flattening and amotivation might be an adaptation to NA. On the other hand, studies of anhedonia have suggested that NA might contribute to anhedonia by reducing pleasure seeking behavior, 86 which could reflect a form of secondary negative symptoms, and that ratings of anhedonia, specifically anticipatory pleasure, is reduced by NA.…”

Trait emotional experience in individuals with schizophrenia and youth at clinical high risk for psychosis

“…38,43 Negative symptoms do not reflect a singular construct, 49 but rather two broad dimensions reflecting diminished expressivity and diminished motivation and pleasure, or five discrete domains reflecting anhedonia, avolition, asociality, alogia and blunted affect. [50][51][52] Therefore, exploratory analyses examined associations between trait affect and the two broad negative symptom dimensions, as well as the five domains.…”