RESUMO
BACKGROUND: Despite the importance of effective assessment and treatment of negative symptoms among patients with psychosis, no validated instruments are available in the Republic of North Macedonia. The aim of this paper was to explore psychometric properties, namely factorial structure, internal consistency, convergent and discriminant validity of the Clinical Assessment Interview for Negative Symptoms (CAINS). SUBJECTS AND METHODS: In this cross-sectional study 82 outpatients diagnosed with psychosis (64 with schizophrenia and 18 with bipolar disorder; female=34, mean age=41.05±10.09) were assessed. RESULTS: The exploratory factor analysis revealed two factorial structure of the negative symptoms as measured by the CAINS, i.e. 'expression and motivation' and 'pleasure'. Two items aimed to measure motivation for family relations and motivation for work/school activities loaded on the expression factor instead on motivation and pleasure factor which differs from the original version of the CAINS. Convergent validity was proven by positive relationship to negative symptoms as measured by the BPRS. Positive, but weak correlation with BPRS positive symptoms demonstrated its discriminant validity. Internal consistency of overall CAINS scale and its two subscales was very high. CONCLUSION: The CAINS can be used to assess negative symptoms in individuals with psychosis in the Macedonian clinical context. Consequently, this work can provide a foundation for further clinical advancement and research of negative symptoms in Macedonian healthcare.
