Introduction: Chronic mental disorder manifests as a change or deviation in an individual’s behavior, emotions, experiences, and actions which can make normal life impossible for him or her. People with chronic mental disorders are often treated in psychiatric institutions and social institutions. Among the more important tasks of a nurse in people with a mental disorder, there are the preparation and distribution of medications, which together with psychotherapy are crucial for the treatment and prevention of recurrent episodes and the maintenance of a stable state of mental disorder. Purpose: The purpose of the bachelor’s thesis is to present the specifics of the treatment of persons with chronic mental disorders in connection with the preparation and distribution of medications and to define the competence framework of nursing care providers in the process. Methods: The bachelor’s thesis was created based on a descriptive systematic review of Slovenian and foreign literature. The search for scientific and expert articles took place through the databases Pubmed/Medline, Science Direct, CINAHL, and with remote access to the Digital Library of the University of Ljubljana (DiKUL). Results: Drug therapy is a common problem in the field of psychiatry because of poor patient adherence. Communication skills and the therapeutic attitude of health professionals that they acquire during formal and non-formal education, in psychiatry, and in other fields of healthcare contribute to raising the effectiveness of treatment significantly. In addition to the prescribing physician, the nurse who prepares, administers, and documents that, as well as observes the occurrence of desired and adverse effects, is also important. Discussion and conclusion: Because of the increasing polymorbidity of people with a chronic mental disorder in healthcare and social care institutions, it is necessary to update the knowledge of health workers who make an important contribution to the successful management and treatment of mental disorders through qualitative communication and confidential interpersonal relationships. Depending on their formal education, registered nurses and nurses are assigned different competencies in the field of preparation and application of medicines. Their work is closely intertwined and complementary.