The chronically mentally ill have been described in the past 100 years as a homogeneous category of patients. Consequently two main treatment approaches were adopted based on the assumption that the treatment of such patients must by homogeneous too.

Firstly, one can identify the environmental approach which emphasises the importance of the secondary disabilities and the hospital milieu in order to change the hospitalisation syndrome and behaviour of chronic patients. Secondly one can identify the approach in which the mental illness is assumed to be responsible for the chronic pathology, which is considered to be incurable. A research project of Ziekenhuis De Grote Beek and Rijksuniversiteit Utrecht has been set up to develop a treatment approach in which the heterogeneity of the needs of chronic patients is stressed, as opposed to the homogeneity of patient characteristics. In a series of papers, we will present the results of this research project.