[Delusional depression as differential dementia of the Alzheimer type diagnosis].

For several years, a 68-year-old patient had been treated for a dementia of Alzheimer's type and finally admitted to a closed gerontopsychiatric nursing home. According to information from his relatives, he first developed psychotic symptoms 3 years prior to admission in our psychiatric department. Several months later, he developed a lack of drive, lack of interests, and reduced emotional reaction. After a standard diagnostic work-up (psychiatric, neurological, and general medical examination, CSF examination, laboratory analyses, cranial computerized tomography), we began electroconvulsive therapy (ECT) with a working hypothesis of major depression with psychotic symptoms. The ECT was able to ameliorate rapidly the psychiatric status of the patient. After 10 weeks of inpatient treatment, he could be discharged from the hospital and was able to take up his usual professional activities on a voluntary basis. This article describes the need for an early differential diagnosis of dementias. Standardized and differential diagnoses of dementias are necessary for an antidementive therapy as well as for the detection of potentially curable diseases.