Background: The most common psychiatric diseases in the geriatric population are depression, the acute confusional state or delirium and dementia.
Methods: A prevalence-day study of psychopathology was carried out in the elderly population admitted to the hospital for several medical and surgical conditions. The semistructured psychiatric interview (CIS), cognoscitive miniexamination (MEC) and Zung's depression scale (SDS) were administered. When appropriate, a diagnosis was established following the DSM-III-R criteria. 15% of the overall number of elderly patients were excluded because of severe medical disease or surgical operation on the study day.
Results: A 43% prevalence of psychiatric disorders was found. 21% of them had depression and 18% a mental organic disorder with cognitive deficit in the form of dementia (6%), delirium (10%), or both (2%). The depression symptoms were more marked with greater cognitive deterioration, and both were greater with increasing age. In only 10% of the patients considered as psychiatric cases the cooperation of the psychiatric interconsultation team had been requested.
Conclusions: The diagnosis of these diseases (depression, delirium and dementia) is very important because in the elderly population with these disorders a higher morbidity and mortality due to medical causes is found.