Validity and Reliability Study of Turkish Version of Clinical Assessment Interview for Negative Symptoms (CAINS)

This study aims to translate and investigate the validity and reliability of the Turkish version of the Clinical Assessment Interview for Negative Symptoms (CAINS), which has additional features compared to other scales in assessing negative symptoms in patients with schizophrenia.

The Turkish version of CAINS was constructed upon an initial translation to Turkish, and an English back translation of the scale was later conducted. The patients diagnosed with schizophrenia (n=79) according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria were administered the Turkish version of CAINS, the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), the Scale for the Assessment of Positive Symptoms (SAPS), the Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression Scale (CGI), the Global Assessment of Functioning Scale (GAF) and the Simpson-Angus Extrapyramidal Side Effects Assessment Scale (SAS). In addition, two interviewers assessed the video recordings of 11 patients for reliability analysis.

Inter-rater reliability was found to be high (intraclass correlation coefficient (ICC): 0.831). Exploratory and confirmatory factor analyses indicated that Cronbach's alpha was 0.956 for the full scale, and the two-dimensional structure explained the scale better. In convergent validity analyses, CAINS overall scores correlated significantly with the SANS total score (r=0,932) and PANSS negative score (r=0,902). In discriminant validity analyses, CAINS overall scores markedly correlated with the SAPS total (r=0,615), PANSS positive (r=0,497) and PANSS general psychopathology (r=0,737) scores. Additionally, when CGI and GAF scores were considered covariant, the significant correlation of CAINS total scores with the SANS total and PANSS negative scores continued; however, the correlation with PANSS positive score was prominently reduced, and the correlation with PANSS general psychopathology disappeared.

The Turkish version of the CAINS appears to be a valid and reliable tool with strong psychometric properties in a sample consisting of patients with schizophrenia.