Recognition of drug abuse in psychiatric inpatients is important. It may influence not only the psychiatric symptomatology, but also the long term course of the illness, especially psychosis. In this study the use of drugs (including excessive amounts of alcohol) was analysed in 172 consecutive admissions in a closed ward of an urban general psychiatric hospital. The psychiatric symptomatology was also evaluated. In the month before admission, 42% of all the patients did use drugs and/or excessive alcohol. In younger man, this was the case in 64%. They mainly used cannabis, alcohol and/or cocaine. Compared to the non-users, the actual users were more often hostile and psychotic at the time of admission. They were diagnosed more often as having a non-affective psychotic disorder. When taking the results in account, it is recommended that more attention should be given to the influence of substance use in the treatmentprogrammes.