Validation of the German version of the Clinical Assessment Interview for Negative Symptoms (CAINS).

Validated assessment instruments could contribute to a better understanding and assessment of negative symptoms and advance treatment research. The aim of this study was to examine the psychometric properties of a German version of the Clinical Assessment Interview for Negative Symptoms (CAINS). In- and outpatients (N=53) with schizophrenia or schizoaffective disorder were assessed with standardized interviews and questionnaires on negative and positive symptoms and general psychopathology in schizophrenia, depression, the ability to experience anticipatory and consummatory pleasure, and global functioning. The results indicated good psychometric properties, high internal consistency and promising inter-rater agreement for the German version of the CAINS. The two-factor solution of the original version of the CAINS was confirmed, indicating good construct validity. Convergent validity was supported by significant correlations between the CAINS subscales with the negative symptom scale of the Positive and Negative Syndrome Scale, and with consummatory pleasure. The CAINS also exhibited discriminant validity indicated by its non-significant correlations with positive symptoms, general psychopathology and depression that are in line with the findings for the original version of the CAINS. In addition, the CAINS correlated moderately with global functioning. The German version of the CAINS appears to be a valid and suitable diagnostic tool for measuring negative symptoms in schizophrenia.