Validation of the Lithuanian Version of the BNSS, CDSS, and the SCoRS

The Lithuanian Brief Negative Symptoms scale (BNSS) version will be used and validated. BNSS is used as a modern tool for the evaluation of negative symptoms of schizophrenia. Older tools used for negative symptoms evaluation often include symptoms from other dimensions of symptoms of schizophrenia, and BNSS evaluates negative symptoms specifically. BNSS is a semi-structured interview made of 13 items. There are six subscales: anhedonia (3 items), lack of normal distress (1 item), asociality (2 items), avolition (2 items), blunted affect (3 items) and alogia (2 items).

The Lithuanian version of the CDSS will be used and validated. CDSS is a tool used to evaluate depressive symptoms, specifically for patients with schizophrenia. Often, distinguishing between depressive and negative symptoms of schizophrenia is difficult. Therefore, it is recommended to use tools designed specifically for patients with schizophrenia. CDSS is the only depression scale designed to assess depression in people with a schizophrenia syndrome disorder. It is a semi-structured interview consisting of 9 items.

The Lithuanian version of the SCoRS will be used and validated. SCoRS is a 20-item interview-based assessment tool that evaluates cognitive deficits and the degree to which these deficits impair specifically in patients with schizophrenia.