Rajna is an Adult psychiatrist, a subspecialist in the field of Social psychiatry, as well as a licensed psychotherapist. She is also a Child and adolescent psychiatrist. Today, her main clinical focus lies in diagnosing and implementing a variety of therapeutic approaches in treating neurodevelopmental disorders. Rajna is involved in a project of ESSENCE knowledge spreading in undeveloped countries, and she is an active member of the Autism Spectrum Disorder International Consortium (ASDIC).

As assistant professor at the Department for Psychiatry and Psychological Medicine, Faculty of Medicine, University of Rijeka, Croatia, Rajna Knez actively participates in conducting various class activities. She has initiated and designed the elective course Child psychiatry - challenges and opportunities where she now stands as course coordinator.

She has completed the postgraduate study Social psychiatry and addiction disease, and one of her research interests focuses on alcohol and drug misuse. She is also interested in adolescents’ eating attitudes, which was the theme of her master’s thesis. Rajna’s PhD was in the field of consultation psychiatry, and mainly focused on children and adolescents with chronic somatic illness and the way such illness affects the entire family’s quality of life. Along with her ongoing active participation in the International Child Mental Health - Study Group (ICMH-SG) projects, she continuously follows her interest in cross-cultural psychiatry research.