The changes in the mental hospital make rather high demands on staff and patients. There is a growing insight that the approach toward the patients should be different from the traditional doctor-patient relationship. In this paper we describe how process consultants look at the process of building new types of collaborative behavior in the hospital staff. We discuss in detail some of the underlying values and principles of behavioral change. The resistance to change is discussed in ways to overcome this problem. In the end attention is given to the idea that process consultants are not pure technologists, but introduce with their organisational development efforts new ways of thinking, of problem solving and handling of conflict to the hospital. This means that efforts of the consultant may change the culture of mental hospital considerably.