Disentangling the symptoms of schizophrenia: Network analysis in acute phase patients and in patients with predominant negative symptoms

Abstract

Introduction: The Positive and Negative Syndrome Scale (PANSS) is widely used in schizophrenia and has been divided into distinct factors (5-factor models) and sub-factors. Network analyses are newer in psychiatry and can help to better understand the relationships and interactions between the symptoms of a psychiatric disorder. The aim of this study was threefold: 1, to evaluate connections between schizophrenia symptoms in 2 populations of patients (patients in the acutely exacerbated phase of schizophrenia and patients with predominant negative symptoms [PNS]), and 2, to test whether network analyses support the Mohr 5 factor model of the PANSS and the Kahn 2 factor model of negative symptoms, and finally 3, to identify the most central symptoms in the two populations. Methods: Using pooled baseline data from 4 cariprazine clinical trials in patients with acute exacerbation of schizophrenia (n=2193) and the cariprazine-risperidone study in patients with PNS (n=460), separate network analyses were performed. Network structures were estimated for all 30 items of the PANSS. Results: While negative symptoms in patients with an acute exacerbation of schizophrenia are correlated with other PANSS symptoms, these negative symptoms are not correlated with other PANSS symptoms in patients with PNS. The Mohr factors were partially reflected in the network analyses. The 2 most central symptoms (largest node strength) were delusions and uncooperativeness in acute-phase patients and hostility and delusions in patients with PNS. Conclusion:This network analysis suggests that symptoms of schizophrenia are differently structured in acute and PNS patients. While in the former, negative symptoms are mainly secondary, in patients with PNS, they are mainly primary. Further, primary negative symptoms are better conceptualized as distinct negative symptom dimensions of the PANSS.

Primary and Secondary Negative Symptoms in Schizophrenia

“…This five-factor model of negative symptoms in schizophrenia has recently been also confirmed with independent network analysis (38). Volitional impairment and, above all, goal-oriented behavior seem likely to be core negative symptoms in schizophrenia, as in this disease, the reward system, and goal-directing planning are disturbed (39).…”

Depressive Symptoms and PANSS Symptom Dimensions in Patients With Predominant Negative Symptom Schizophrenia: A Network Analysis

“…Another important finding is that the network analysis, including both the PANSS and the CDSS items, clearly confirms the Mohr 5-factor model of the PANSS: the negative symptom factor, the hostility/excitement factor, the positive symptom factor, the cognitive factor and the mood factor are visually easily recognizable ( 7 ). This confirms a recently published study where this structure was also easily recognizable in both an acute patient population and in a population with predominant negative symptoms ( 6 ).…”

“…The association between negative symptoms and depressive symptoms has not been sufficiently investigated and results are inconsistent ( 22 ). It should be remembered that in patients with schizophrenia negative symptoms can be primary or secondary and while in our selected population the negative symptoms are primary ( 6 ). This problem of differentiation between negative symptoms and depressive symptoms was already suggested in DSM-IV where it was stated that negative symptoms are difficult to evaluate and that a more phenomenological understanding can be helpful: depressive symptoms are considered to be associated with intense painful affect while negative symptoms are associated with diminution of affect and emptiness ( 23 ).…”

“…Although several factor analyses studies have suggested that a 5-factor model captures PANSS structure better than the original PANSS subscales, no single model has achieved broad consensus, and the 3 original subscales are still widely used. In a recent paper, a network analysis illustrated the validity of the Mohr model ( 6 ).…”

Prevalence, Influencing Factors, and Clinical Characteristics of Cognitive Impairment in Elderly Patients With Schizophrenia

“…The mini-mental state examination (MMSE) is one of the most commonly used assessment tools in the field of geriatric cognition ( 14 , 15 ). It mainly involves attention, recall, language, localization, registration, and calculation skills, and the score ranges from 0 to 30, with a lower score indicating poorer cognitive ability ( 16 ).…”