 In comparison to SCL-90-R it differs mainly in the lack of items referring to psychotic symptoms and inclusion of questions about the most common symptoms in patients with neurotic disorders observed between 1975 and 1978.KO "O" was designed as one of a set of tools used for collecting information about patients who begin treatment due to psychogenic functional disorders, and especially neurotic disorders.KO "O" was originally developed in Polish and later English, German and Russian adaptations of the questionnaire were created.