Dutch Validation of the Self-Evaluation of Negative Symptoms scale (SNS)

Tim VAN BROUWERSHAVEN², Anika POPPE^2,3, Marieke PIJNENBORG^3,4, André ALEMAN^3,5, Sonia DOLLFUS⁶, Lisette VAN DER MEER^2,3

¹Universitair Hoofddocent, Groningen, Netherlands
²Lentis Psychiatric Institute, Groningen, Netherlands
³University of Groningen, Groningen, Netherlands
⁴GGZ Drenthe, Groningen, Netherlands
⁵University Medical Center Groningen, Groningen, Netherlands
⁶Psychiatry Department, University of Caen Normandy, France, Caen, France

Background

Negative symptoms are related to impaired social functioning and lower quality of life, making accurate assessment important. To date, most tools for assessing negative symptoms are observational, which can be influenced by the raters’ experience and opinion. Self-rating scales could complement objective ratings by adding information from the patient’s perspective. To this end, Dollfus and colleagues developed a self-assessment scale for negative symptoms that can be completed in 5 minutes: The Self-Evaluation of Negative Symptoms (SNS). Here, we aim to evaluate 1) the psychometric properties of the Dutch translation of the SNS and 2) the relationship between the SNS and functional outcomes.

Methods

The SNS was added to the Pharmacotherapy Monitoring Outcome Survey (PHAMOUS)-protocol for adult individuals with a DSM-5 diagnosis of a psychotic disorder. Internal consistency was assessed by Cronbach’s alpha. Confirmatory factor analysis was used to evaluate the construct validity of the five subscales. The relationship between self-reported negative symptoms and interview based negative symptoms, social functioning, global functioning, functional remission and quality of life was investigated through correlational analyses of the SNS with the Positive and Negative Syndrome Scale (PANSS), the Health of Nation Outcomes Scales (HoNOS), the Global Assessment of Functioning (GAF), functional remission and the Manchester Short Assessment of Quality of Life (ManSA).

Results

340 patients participated in this study. Internal consistency was good (α=0.88). CFA confirmed the five factor structure of the SNS. Correlational analyses showed that the SNS is significantly correlated with the HoNOS (r = 0.32, p <.001) and the ManSA (r = -0.43, p <.001).

Discussion

Here, we showed that the Dutch SNS shows good psychometric properties and can be used to self-assess negative symptoms.