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

This study aims to validate the Lithuanian version of the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale in a Lithuanian sample. This will be done by comparing results obtained from the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale with results obtained from the Positive and Negative Symptoms Scale, the Montgomery Asberg Depression Rating Scale, and the Montreal Cognitive Assessment test.

This scale validation study aims to validate the Lithuanian version of the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale Schizophrenia Cognition Rating Scale in the Lithuanian sample. The main aim of this study is:

• to evaluate the convergent and discriminant validity of Lithuanian versions of the Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale.

Participants will be evaluated using the Positive and Negative Symptoms Scale (PANSS), Montgomery Asberg Depression Rating Scale (MADRS), Montreal Cognitive Assessment (MoCA) test, Brief Negative Symptoms Scale, Calgary Depression Scale for Schizophrenia, and Schizophrenia Cognition Rating Scale.

To discern the discriminant validity of the Brief Negative Symptoms Scale for negative symptoms, results from the Brief Negative Symptoms Scale will be compared to results from the positive and general subscale of the Positive and Negative Symptoms Scale and the Montgomery Asperger Depression Rating Scale. To discern the convergent validity of the Brief Negative Symptoms Scale for negative symptoms, results from the Brief Negative Symptoms Scale will be compared to the results from the negative subscale of the Positive and Negative Symptoms Scale and the Self-evaluation of Negative Symptoms scale.

To discern the discriminant validity of the Calgary Depression Scale for Schizophrenia for depressive symptoms of schizophrenia, results obtained from the Calgary Depression Scale for Schizophrenia will be compared to results obtained from the Positive and Negative Symptoms Scale and the Self-evaluation of Negative Symptoms scale. To check the convergent validity of the Calgary Depression Scale for Schizophrenia, results obtained from the Calgary Depression Scale for Schizophrenia will be compared to results obtained from the Montgomery Asperger Depression Rating Scale.

Finally, to check the discriminant validity of the Schizophrenia Cognition Rating Scale, results obtained from the Schizophrenia Cognition Rating Scale will be compared to results obtained from the Montgomery Asperger Depression Rating Scale and the Positive and Negative Symptoms Scale. In contrast, to prevent convergent validity, results obtained from the Schizophrenia Cognition Rating Scale will be compared to results obtained from the Montreal Cognitive Assessment test.

Eligibility Criteria:
Inclusion Criteria:

* age 18 - 65 years old;
* Diagnosis of F20, F25 or F21 according to ICD-10;
* Signed informed consent form.

Exclusion Criteria:

* Age younger than 18 or older than 65 years old;
* Did not sign the informed consent form;
* Legally inactive person
* Patients with a comorbid or primary diagnosis of mental retardation according to ICD-10 (F70 - F79);
* Patients with a comorbid or primary diagnosis of mental and behavioural disorders due to psychoactive substance use (F10 - F19)
* Patients with a comorbid of primary diagnosis of organic, including symptomatic, mental disorders (F00 - F09)