Elmer Goudsmit MD PhD directs the IST-Lux and facilitates and manages the training program.


After obtaining his PhD in brain research in Amsterdam, he trained as psychiatrist and psychotherapist in Maastricht, the Netherlands. From 1999 onwards he pursued further training in systemic therapy, cognitive behavioral therapy and schema therapy. He is a certified advanced level schema therapist since 2009 and trainer/supervisor since 2010. He participates as trainer/supervisor in the schema therapy training programs in Berlin, Cologne, Frankfurt and Dresden and is adjunct senior lecturer at the university of Luxembourg (Master in Psychotherapy Program). At the Center for Psychotherapy of the Humboldt University in Berlin (ZPHU) he offers self-therapy seminars for psychotherapists in training. He works in private practice in Luxembourg.

Jan Kossack is a licensed psychologist and psychotherapist. In addition, he has a DAS as Forensic Psychotherapist form the University of Zurich.


Since 1998 he works in Luxembourg and in Spain as a psychotherapist/psychologist with adolescents, families, couples and individuals.


Jan Kossack is an advanced level certified Schema Therapist since 2014 and is certified as trainer/supervisor by the ISST. He offers training and supervision in schema therapy in Luxembourg, Spain, Paris/France and in Lausanne/Switzerland.

Dirk Leonhard is a trained and licensed psychologist/psychotherapist and neuropsychologist.


During various positions in neurologic, psychosomatic and psychotherapeutic clinics he gained extensive professional experience. He qualified as a psychotherapist in cognitive-behavioral therapy in 2008 and works since 2009 in private practice in Luxembourg. He participates as a supervisor in the “Master in Psychotherapy Program” at the University of Luxembourg. In 2018 he obtained ISST-certification as an advanced level schema therapist by and in 2019 he was certified as trainer/supervisor.

·        Marianne Barthelemy-Schomer is a trained and licensed psychologist/psychotherapist (CBT)).


      Marianne also is a professional singer (music study at the conservatory) and offers voice training and music therapy. She is certified as an advanced level schema therapist with the ISST since 2019 and in the process of obtaining her trainer/supervisor certification. She plays a crucial role in the organization of the training program and offers practical support and assistance in the training-modules.