The psychometric properties of the Nepean Belief Scale as a tool for assessing delusions in schizophrenia and related psychotic disorders

Reliability and validity of the Nepean Beliefs Scale for delusions and overvalued ideas in chronic schizophrenia: analysis of a preliminary pilot study

Introduction

The Nepean Beliefs Scale by Brakoulias et al. is an interview-based multidimensional instrument that measures pathological beliefs in various psychiatric disorders. This study examined the reliability and validity of Nepean Beliefs Scale (NBS) for delusions and overvalued ideas in patients with chronic-phase schizophrenia. Methods: Multiple raters at two healthcare settings examined the beliefs of 28 individuals with schizophrenia using the NBS. Concurrently, PANSS, PDI-21, BCIS, PHQ-9 and GAD-7 were administered.

Results

The NBS had high reliability and correlation with relevant scales.

Discussion

The NBS was found to have sufficient reliability and validity for assessing the pathological beliefs of patients with chronic schizophrenia. Although NBS is an easy-to-instruct instrument, it should be noted that appropriate explanations and examples should be added to instructions to obtain reliable responses from patients with chronic schizophrenia.

The Nepean Belief Scale (NBS) as a tool to investigate the intensity of beliefs in anorexia nervosa: psychometric properties of the Italian version

BACKGROUND

People with anorexia nervosa (AN) show a peculiar impairment of insight regarding their condition, often manifesting a denial of extreme emaciation and sometimes hiding or underreporting socially undesirable abnormal eating patterns. Sometimes the intensity of the beliefs held by patients with AN reach a delusional intensity.

OBJECTIVES

In this study, the Italian version of the Nepean Belief Scale was applied to a sample of patients diagnosed with AN to investigate the intensity of their beliefs and convictions and its clinical correlates.

METHODS

The Nepean Belief Scale (NBS) was translated and adapted to Italian and applied to a sample of patients diagnosed with AN based on the Structured Clinical Interview for DSM-5 (SCID-5).

RESULTS

The Italian version of the 5-item NBS showed excellent reliability. Convergent validity was proved by negative association with levels of insight measured with the Schedule for the Assessment of Insight in Eating Disorders. Beliefs of delusional intensity were reported by 10% of participants. Those with a greater intensity of beliefs, either overvalued or delusional ideas, were more likely to report poorer general cognitive performances on the Montreal Cognitive Assessment. No association was observed between NBS score and age, body mass index, symptoms of eating disorders, body dissatisfaction, or levels of depression. Fear of weight gain and control seeking were the most often reported themes at the NBS.

CONCLUSIONS

The Italian version of the NBS is a reasonably reliable, valid, and usable tool for the multidimensional assessment of insight in AN. Level of evidence Level III, Evidence obtained from well-designed cohort or case-control analytic studies.