Background: Drug prescriptions were studied in two samples of inpatients that differentiated by their ages (patients 18-64 years vs elderly patients > 64 years), in order to compare the use of psychotropic and non-psychiatric drugs, and the proportion of newer versus classical antidepressants or antipsychotics. Methods: Drug prescriptions were recorded on a reference day in May 2000 in two hospitals that differed in the age categories of the patients who were admitted. The total costs per patient were compared, as well as the proportion of those due to a somatic medication. Results: The prescriptions of 61 adult patients and of 82 psychogeriatric patients were assessed. The mean number of prescribed somatic drugs per patient was higher in elderly patients (P < 0.001), which was again reflected in a higher mean number of all drugs jointly (P < 0.001). Prescription of benzodiazepines was lower in elderly patients than in the adult patients (P < 0.001), even when used as an add-on treatment with antidepressants (P < 0.001). The pharmacological treatment of adult patients was significantly less expensive (9.3 +or- 7.2 Swiss Francs/patient) than that of the psychogeriatric patients (14.1 +or- 9.5 Swiss Francs/patient; P = 0.009), who had a higher need for somatic comedications. Conclusions: This survey confirms the large impact of local traditions on the prescription habits of clinicians, with the exception of the prescription of benzodiazepines, regarding which psychiatrists of psychogeriatric patients seem to be less enthusiastic. (PsycINFO Database Record (c) 2007 APA, all rights reserved) (journal abstract)