In the 1960s Nossrat Peseschkian set up his own psychiatric practice in Wiesbaden, Gemany. Free from external constraints, he was able to work with patients during the next thirty years in his own therapeutic style and develop it further. He discussed his new ideas for psychotherapy from 1968 on with his co-workers Dieter Schön, MD, and with Hans Deidenbach (Psychologist). This ultimately led to the development of Positive Psychotherapy.
Prof. Peseschkian started to develop Positive Psychotherapy in the late 1960s and early 1970s. The development of this concept of PPT involved the investigation of the relationship between culture and disease and of the cultural concepts in 22 different cultural groups. He was also the founder and former director of the Wiesbaden Academy for Psychotherapy and the director of the International Academy of Positive and Transcultural Psychotherapy – Peseschkian Foundation. He was a reader at the Academy for Higher Medical Education of the State Medical Chamber of Hesse, Germany.
As international lecturer, Prof. Peseschkian gave talks at universities and colleges in many countries, e.g. in the USA, Hawaii, Canada, New Zealand, Australia, Papua New Guinea, Kenia, Japan, China, India, Brazil, Bolivia, Switzerland, Austria, Russia, Ukraine, Turkey, Cyprus, Bulgaria, Germany.
In 1997 he was awarded the Richard Mertens Prize for his work “Computer Assisted Quality Assurance in Positive Psychotherapy”. This Prize is one of the highest awards of quality assurance in the medical field in Europe.
In January 2006, Prof. Dr. Nossrat Peseschkian received the Order of Merit, Distinguished Service Cross of the Federal Republic of Germany (Bundesverdienstkreuz).
Prof. Dr. Nossrat Peseschkian was the author of numerous books on psychotherapy. 26 books on Positive Psychotherapy have been partly published in 24 languages, and have been among the first ones in Eastern Europe. Translated versions of his books are available for example in Chinese, Russian, English and Spanish. More than 250 articles have been published in scientific magazines.
 Peseschkian N. Positive family therapy. The family as therapist. Berlin, Heidelberg: Springer; 1986. (first German edition in 1980, latest English edition in 2016 by AuthorHouse UK)