The course of the psychopathology of an experimental day treatment group, accepted for admission in a psychiatric hospital, was compared with that of a control group, receiving standard clinical care. In a follow up period of two years the subjects were interviewed three times: at entry into the study, and after one and two years. The interview comprised information about psychiatric symptoms, psychological functions and psychiatric diagnoses. Apart from these discrete assessments, an effort was made to map spells of illness throughout the follow up period (continuous assessment).

At entry the groups did not differ in terms of psychopathology. At follow up both groups had improved significantly with respect to symptomatology and impairment in psychological functioning. The extent to which the groups improved did not differ significantly. The average length of spells of illness was similar for the experimental and the control group. During the two year follow up period, on average the patients suffered from a well defined (DSM-III) disorder during 11 months. The fact that about 40% of them was still a psychiatric case after 2 years, further underscores the severity of their pathology.