Patients who show an above-average utilization of medical care are described as "heavy users". Heavy utilization of psychiatric inpatient care could be reduced by well directed community based services. Heavy users should, therefore, be identified at the beginning of a period of heavy service consumption. For this reason, a screening instrument (SPSI) was developed. Six predictors of heavy utilization of inpatient care were included as items in the SPSI. Weighting of items and examination of the instrument were carried out with a sample of 184 schizophrenia patients, whose utilization of inpatient care was recorded prospectively over a period of 30 months. 83 percent of heavy users and 85 percent of ordinary users were correctly identified with the SPSI test at a cutoff score of - 6.7. The SPSI is a short questionnaire which could be used without special rater training in psychiatric care in order to offer identified heavy users well directed community based services, which are less costly than inpatient care, but at least just as appropriate for the special needs of these patients.