Validation of the Turkish version of the self-evaluation of negative symptoms scale (SNS)

Abstract

Objectives

The Self-Evaluation of Negative Symptoms Scale (SNS) is a self-report scale that evaluates a patient’s subjective experience on all five domains of the negative symptoms. This study aimed to present the adaptation and validation study of the Turkish version of SNS(SNS-TR).

Methods

Seventy-five patients and 50 controls were recruited for this study. After the approval of the translation, participants were asked to fill out SNS-TR by themselves. They were interviewed with the Brief Negative Symptoms Scale (BNSS), Positive and Negative Syndrome Scale (PANSS), and Calgary Depression Scale for Schizophrenia (CDSS).

Results

SNS-TR showed good internal consistency in the reliability analysis with Cronbach’s alpha= 0.873. Subscale-total score correlation coefficients were significant (p < 0.01). In the validity analyses, the total and subscale scores of SNS-TR showed positive correlations with the total and subscales of BNSS, with only one exception of BNSS lack of distress subscales. The total score of SNS-TR demonstrated a significant correlation with PANSS-total, PANSS-negative subscale, PANSS-general subscale, and CDSS scores. Confirmatory factor analysis showed acceptable values for the five-factor structure, similar to the original version.

Conclusion

To conclude, our study indicates that SNS-TR is an easily applicable self-evaluation tool with good psychometric properties for assessing negative symptoms.

KEY POINTS

• SNS is a novel and easily applicable self-report scale for examining negative symptoms in schizophrenia patients, allowing them to evaluate their subjective experience on all five domains of the negative symptoms.

• It shows good internal consistency (α= 0.873) which is similar to the original version (α = 0.867).

• Confirmatory factor analysis scores were found in acceptable ranges and SNS-TR confirm the five-factor structure.

• Using this scale in clinical practice would empower both the physician’s examinations and patient participation through treatment and follow-up course.

Keywords:

• Negative symptoms
• self-evaluation
• SNS
• schizophrenia
• validation

Acknowledgments

The authors thank Vincent Bouvard and Ilona Bouvard for their contributions to the translation and back-translation process.

Disclosure statement

The authors have nothing to disclose related to this study.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.