Aim: Construct stability over time is required for reliable inference, but evidence regarding the longitudinal invariance of negative symptoms is still limited. Thus, we examined the longitudinal invariance of the negative dimension using the positive and negative syndrome scale (PANSS) in an antipsychotic-naïve first-episode schizophrenia sample at baseline and after 10 weeks.Methods: Our study was conducted at a specialized early intervention service. PANSS ratings were analysed for 138 patients, and two different models were specified and tested: a unidimensional and a two-correlated factor solution.Results: The unidimensional model fulfilled criteria for longitudinal invariance, whilst the two-correlated did not. Conclusion:Our study provides support for the PANSS negative unidimensional model use to evaluate negative symptoms' longitudinal change following firstepisode schizophrenia.
Background Determining the best latent structure of negative symptoms in schizophrenia could benefit assessment tools, neurobiological research, and targeted interventions. However, no review systematically evaluated studies that assessed and validated latent models of negative symptoms. Objective To identify and evaluate existing latent structure models in the literature of negative symptoms and to determine the best model. Method Systematic search of MEDLINE, EMBASE, and Scopus on July 19, 2020, for confirmatory factor analysis models of negative symptoms in patients with schizophrenia. The available evidence was assessed through 2 sets of criteria: (1) study design quality—based on negative symptoms assessment and modeling strategy and (2) psychometric quality and model fit—based on fit indices and factor definition quality. Results In total, 22 studies (n = 17 086) from 9 countries were included. Studies differed greatly regarding symptom scales, setting, and sample size (range = 86–6889). Dimensional models included 2–6 factors (median = 4). Twelve studies evaluated competing models and adopted appropriate instruments to assess the latent structure of negative symptoms. The 5-factor and hierarchical models outperformed unitary, 2-factor, and 3-factor models on all direct comparisons, and most of the analyses derived from the Brief Negative Symptom Scale. Considering the quality criteria proposed, 5-factor and hierarchical models achieved excellent fit in just one study. Conclusions Our review points out that the 5-factor and hierarchical models represent the best latent structure of negative symptoms, but the immaturity of the relevant current literature may affect the robustness of this conclusion. Future studies should address current limitations regarding psychometric properties and also address biological and clinical validity to refine available models.
Background Negative symptoms are associated with a range of poor clinical and real-life functioning outcomes in people with schizophrenia. The division of negative symptoms into two separate factors, named “expressive deficits” and “social amotivation” could enable more accurate analysis and the development of new therapeutic tools. We aim to investigate whether the different symptoms that make up the negative dimension at baseline differently predict treatment response in first episode psychosis (FEP) antipsychotic naïve patients. Methods Patients with FEP (n=80), without previous use of antipsychotics, were recruited at an emergency service in São Paulo, Brazil, between 2014 and 2019. Individuals were assessed at admission and after 10 weeks of follow-up. Patients with schizophrenia, schizoaffective disorder and schizophreniform disorder were included. The diagnosis was confirmed using the Structured Clinical Interview for DSM-IV Disorders (SCID-I). Patients were evaluated with the Positive and Negative Syndrome Scale (PANSS) at the baseline and after 10 weeks of treatment. The “expressive deficits” factor was defined as the sum of the six following items of the PANSS: N1 (blunted affect), N3 (poor rapport), N6 (lack of spontaneity and flow of conversation), G5 (mannerisms and posturing), G7 (motor retardation), G13 (disturbance of volition). The “social amotivation” factor was defined as the sum of N2 (emotional withdrawal), N4 (passive/apathetic social withdrawal) and G16 (active social avoidance). To evaluate treatment response, we used the difference between the PANSS score at baseline and after ten weeks of follow-up (delta-PANSS). We performed three linear regressions, one using the “expressive deficits” factor, one using the “social amotivation” factor and another using the total negative symptom score at baseline. Results The mean age was 26.01 years old (SD ± 7.2), and the majority was male (58.75%). “Expressive deficits” (p=0.005, R-squared=0.084, F-test=8.28, β=8.24, df=78), “social amotivation” (p=0.009, R-squared=0,072, F-test=7.14, β=5.59, df=78); and negative symptoms (p=0.002, R-squared=0.105, F-test=10.23, β=9.08, df=78) at baseline behaved similarly in relation to delta-PANSS. All measures of negative symptoms are highly correlated to PANSS total at both time points. Discussion The results were different from our initial hypothesis of worse outcome for patients with higher expressive negative symptoms. We found that negative symptoms overall and both subdomains are highly correlated to PANSS total in acute phase in early stages, what can explain the association to better outcomes with antipsychotic treatment. Longer follow-up can help us to investigate whether differences between the subdomains of negative symptoms can be observed in more stable patients.
Background Despite the progress in treatment and clinical outcomes, schizophrenia remains a highly stigmatized disease and imposes a challenge to families and patients towards recovery. Stigma can debilitate individuals as much as the disease itself, representing one of the most relevant obstacles to overcome the illness: it hinders the pursuit of autonomy and achievement of life goals. Stigma is complex and multilayered and its research usually focus on patients and society, but a lower number of studies address health professionals stigma. Even fewer investigate stigma of researchers. Thus, our objective is to analyze how the most cited research papers published in 2018 addressing schizophrenia depict the disease to identify putative stigma among researchers. Methods In this exploratory study, we conducted a search using Web of Science (WoS) with the following terms: (“patients with schizophrenia”) OR (“schizophrenia patients”). We restricted the search to articles published in 2018 and selected the 20 studies with the highest total number of citations. We identified how the authors defined schizophrenia and then categorized the definition in three groups: (1) negative perspective, in which depreciative words were used to define the disease; (2) neutral definition, in which emphasis is given to the description of epidemiological data; and (3) neutral to positive definition, when negative outcomes were listed as possibilities, not certainties. Two independent authors (G.K. and M.M.) categorized each article and eventual conflicts were solved by a third author (A.G.) Results 25% of the studies depicted a clearly negative perspective of schizophrenia. In these studies, the disease was described with words such as “devastating” and “highly disabling”. Most studies (60%) were coded as neutral, being mainly descriptive of current epidemiological data. Only 3 studies (15%) were identified as more favorable, since they acknowledged the possibility of better outcomes among patients with schizophrenia. Discussion In the current schizophrenia scientific literature, negative views of the disease are still largely common. Considering the role of highly cited papers as opinion formers, we suggest that as occurred in other fields, such as the change in address of suicide by the media, some orientation should be adopted to avoid further contributions to the schizophrenia stigma.
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