Fourth, we showed that a five-domain construct in relation to the 5 consensus domains (social withdrawal, anhedonia, alogia, avolition, blunted affect) was the best latent structure of the SNS since recent studies using the BNSS suggested that this model has better fit statistics than a 2-dimensional construct ( 25). Third, we evaluated the capacity of the SNS compared to the BNSS to detect negative symptoms by investigating the frequency of negative symptoms in a large sample. Second, we tested the relationships between the SNS and patients' functional outcome and particularly the load of avolition since strong correlations between this dimension and functional outcome has previously been reported ( 21– 24). Of note, the relationships between the SNS and the BNSS, which is a valid and reliable instrument for assessing negative symptoms of schizophrenia across cultures ( 18), needed to be explored since most of the previous studies with the SNS tested convergent validity with the negative subscale of the Positive and Negative Syndrome Scale (PANSS) ( 16, 19) or with the Scale for the Assessment of Negative Symptoms (SANS) ( 5, 12, 20). First, we demonstrated good convergent and divergent validities. Therefore, the aim of this paper was to validate the SNS in a large European sample coming from 12 countries. Despite all these studies were conducted in different countries (France, US, Spain, Poland, China, and Lebanon) further validation studies of the SNS are necessary, particularly on larger samples and in various European Countries. Arabic and Chinese versions of the SNS in patients with schizophrenia were also used showing that all items converged over a solution of five factors ( 16, 17). A SNS total score threshold at 7 for the identification of the negative dimension of schizophrenia with good sensitivity and specificity has also been established ( 15). Other studies in French, American, and Polish populations confirmed similar good psychometric properties ( 12– 14). In the first and main validation study, the SNS demonstrated a good test-retest reliability, good internal consistency, and tight convergent and divergent validities ( 5). However, similar to HA scales, SA scales, using traditional or innovative methods ( 11), need to present good psychometric properties in order to be used them in therapeutic trials or in clinical practice. They are easier to understand, more time-efficient since they need less time for the evaluation, they better assess subjective feelings and increase a patient's involvement in the treatment, and they might be more appropriate to detect the symptoms during a first psychotic episode ( 9) at the beginning or even before the onset of illness ( 10). Nevertheless, SA have several advantages over HA. In contrast, 18 HA scales ( 6) have been developed with the two most recent scales being the Brief Negative Symptom Scale (BNSS) ( 7) and the Clinical Assessment Interview for Negative Symptoms (CAINS) ( 8). Indeed, only five self-report tools have been introduced ( 3) only two of them have been considered as self-assessments sensu stricto, the Motivation and Pleasure Scale–Self-Report (MAPSR) ( 4) and the Self-evaluation of Negative Symptoms (SNS) ( 5). Negative symptoms are usually evaluated with scales based on observer ratings (as named hetero-assessment, HA) and up to now self-assessments (SA) have been overlooked, probably because of the idea that patients with schizophrenia with negative symptoms are unable to accurately report their own symptoms ( 1, 2).
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