Delirium in elderly patients admitted to a psychiatric hospital: causative factors and treatment

We studied the causes and treatments of delirium in 43 patients admitted to the geriatric-psychiatric ward of a hospital in Japan. Patients studied were divided into three groups according to the type of factor responsible for their delirium. We termed these causal factors precipitating, facilitating and predisposing factors. Twenty-one patients exhibited precipitating factors, the most common of which were overmedication and poisoning. Almost all these cases were treated with psychotropic drugs. Facilitating factors were judged responsible in nine cases. In six of these, admission to a hospital was thought to be the facilitating factor. Thirteen patients who had only predisposing factors were treated with psychotropic drugs while 27% of patients without precipitating factors were successfully treated for delirium without the use of such drugs.