[2][3][4] He studied medicine in Graz and Vienna, where he showed interest in psychoanalysis and attended lectures of Sigmund Freud.

During World War II, in 1941, the Independent State of Croatia authorities sent Betlheim, Stjepan Steiner and 80 other Jewish physicians to Bosnia to treat endemic syphilis.

[5] After the war, in 1948, he became an assistant at the Neurologic-psychiatric Clinic of the School of Medicine, University of Zagreb, where he introduced the psychoanalytical dimension into the understanding of mental illness.

[6] Betlheim was married to Marie Luise (née Morgenroth) with whom he had a daughter named Ruth.

[9] His daughter wrote a book about the life of her father, which was issued and presented in 2006 at the Jewish community in Zagreb.