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.

In the 1970s, Nossrat Peseschkian started to give lectures and continuing education for doctors, which was recognized as psychotherapeutic continuing education by the medical board of Hesse. At the same time the first of his publications appeared. Four of the five basic books of Positive Psychotherapy were published during this period: “Psychotherapy of Everyday life (originally “Schatten auf der Sonnenuhr”, 1974) “Positive Psychotherapy” ([original German] 1977), “Oriental Stories”, ([original German] 1979) about the application of Oriental stories in Positive Psychotherapy, and “Positive Family Therapy” ([original German 1980). He called his new approach “Differentiation Analysis”, which was used until 1977, when his book “Positive Psychotherapy” was first published.

The same period saw the first structure for training in Positive Psychotherapy with the founding of the “Psychotherapeutic Experience Group Wiesbaden” (Psychotherapeutische Erfahrungsgruppe Wiesbaden, PEW) in 1977. The medical board of Hesse gave the authorization for the continuing education in psychotherapy for physicians. The German Association for Positive Psychotherapy (DGPP) was founded in 1977, the first association for Positive Psychotherapy in the world, and published an own Journal on Positive Psychotherapy (original German) since 1979.

Exchanges during his travels with many colleagues, students and other interested persons from many cultures intensified his coming to terms with the cultural particularities of the patients so that he coined the term “Transcultural Psychotherapy” very early (N. Peseschkian, 1977 [German] & 1987 [English translation]).

Nossrat Peseschkian began to give lectures and seminars intensively beyond the borders of Germany during the 1980s which would lead him and his wife, Manije, to more than 60 countries on all five continents. More books were published, such as “In Search of Meaning” (German 1983, English translation 1985).

The First Interview questionnaire and the “Wiesbaden Inventory for Positive Psychotherapy and Family Therapy” (WIPPF) had been published 1988 in cooperation with Hamid Peseschkian and Hans Deidenbach.

The last of the basic works of Nossrat Peseschkian, “Psychosomatics and Positive Psychotherapy” (1991 German & 2013 English translation) was published. Among other things it presents a structured, psychodynamic model of illness and a five step process of psychosomatic treatment.

Positive Psychotherapy attracted great interest in the recently changing countries of Central and Eastern Europe, which lie not only geographically but often also psychologically between East and West. More than 30 centers, beginning with the first in 1990 in Kazan, Russia, and the first National Associations for Positive Psychotherapy in Ukraine, Bulgaria, Romania were established. Active participation in the European Association for Psychotherapy (EAP) started by which the Certified Positive Psychotherapy Trainings were later accredited as qualifying for the European Certificate for Psychotherapy (ECP).

Positive Psychotherapy was further internationalized through the founding of the International Center for Positive Psychotherapy (ICPP) in 1996, the forerunner of today’s World Association for Positive Psychotherapy (WAPP).

In 1997 the 1st World Congress for Positive Psychotherapy took place in St. Petersburg, Russia.

A first “Effectiveness Study of Positive Psychotherapy” conducted in 1995-1997 showed a high therapeutic influence of the method in different diagnosis. For this scientific work Nossrat Peseschkian received the Richard Merten Prize for Quality Assessment.

The trainings in Positive Psychotherapy became more systematised from 1992 on, curricula were set up for basic and advanced trainings in Germany and abroad. Positive Psychotherapy has moved into areas outside medicine, primarily into school and university education, into management training and coaching.

In 2000 the Second World Conference for Positive Psychotherapy in Wiesbaden hosted guests and delegates from around the world including Rick Snyder, who later edited the first Handbook of Positive Psychology. The first Training for Trainers in PPT started to qualify the worldwide trainers.

In 2005 the Peseschkian Foundation – International Academy of Positive and Transcultural Psychotherapy (IAPP) was founded by Nossrat Peseschkian and his wife, Manije. It promotes international activities and administers the International Archives of Positive Psychotherapy. The foundation supports publications, nonprofit and scientific projects and holds the right to the books of Nossrat Peseschkian.

The International Center for Positive Psychotherapy (ICPP) was renamed to World Association for Positive Psychotherapy (WAPP) in 2008. The International Secretariat of the WAPP is located in Wiesbaden.

National associations for Positive Psychotherapy exist in Germany, Russia, Romania, Kosovo, Ukraine, Turkey, and Bulgaria. Positive Psychotherapy is also active with centers in Albania, Austria, Azerbaijan, North Cyprus, Poland, Macedonia, China, and Ethiopia. The first university Master’s Degree course in Positive Psychotherapy was completed in 2005 at UTEPSA University in Santa Cruz in Bolivia. Positive Psychotherapy is also included in curricula for psychology and psychotherapy in universities in Bulgaria, Russia and Turkey.

By 2014, 6 World Congresses of Positive Psychotherapy have taken place at different international locations. Continuous trainings for trainers to maintain high standard education are offered by the WAPP as International Trainer Seminars (ITS) in Germany and by other National Associations, for example in Bulgaria, Romania, and Ukraine.

In 2016 the term “transcultural” was added to the name of the World Association for Positive Psychotherapy (WAPP) to underline the method’s transcultural basis, which is now officially registered as World Association for Positive and Transcultural Psychotherapy (WAPP).