In recent years, economic pressure on extended and repeated psychiatric hospitalisation have increased dramatically. At the same time, diagnostic approaches, e.g., the new concept of the "young adult chronic patient" have improved. The first part of this article summarises reports and experiences on the chronic mentally ill and the so-called "heavy users" of psychiatric hospitalisation. Although the number of studies evaluating this group is small, several characteristics can be identified. Subsequently, a study is presented that deals with psychiatric problem patients in a special way, namely the A2-categorisation according to the German Psychiatric Personnel Regulation (Psychiatrie-Personalverordnung [Psych-PV]). The study is based on 170 consecutive admissions to the Department of General Psychiatry of a large German state hospital, who are characterised as normal (A1) and intensive patients (A2), respectively. The study aimed at describing difficult-to-treat patients or those whose treatment demands large human resources. Medical histories, sociodemographic and psychopathological data as well as subjective health status data of these patients were analysed by standardised and validated instruments (e.g., BPRS, CGI, SF-36, GAF). Results show that the patients under study suffered mainly from schizophrenic psychosis according to ICD-9. Patients categorised into A2 showed a high degree of psychopathology and little insight into their disease. Further it can be demonstrated that they used more therapeutic help from general practitioners rather than from specialists in psychiatry prior to admission. In conclusion, it is suggested to evaluate concepts, e.g., new treatment methods in respect of motivating schizophrenic patients, new typological methods to better diagnosis and to treat psychiatric problem patients via new treatment modalities such as Case Management or inpatient settings for double diagnoses.