From 1978 to 1990 Ziherl was the head of the Centre for Treatment of Alcohol Addiction of the University Psychiatric Hospital in Ljubljana, and from 1994 to 1996 he was the head of the Centre for Clinical Psychiatry of the University Psychiatric Hospital, and until 1998 he was the medical director of the Psychiatric Hospital of the University Medical Centre.
He also held lectures in psychopathology at the postgraduate level at the Ljubljana Faculty of Medicine.
In 1995, he was the representative of the Association of Psychiatrists and Slovenian health care centres in the European Union of Medical Specialists (UEMS), Section of Psychiatry and the European Board of Psychiatry (EBP).
He also wrote about Nazi treatment and extermination of the mentally ill. [1] His bibliography amounts to more than 190 titles.
He also published articles in newspapers and magazines and appeared on radio and television programs.