Dexametazone Suppression Test as a Laboratory Aid for Different Diagnosis Between Depressive Disorders and Dementia in Elderly Patients / תבחין דיכוי הדקסמטזון ככלי עזר מעבדתי לאבחנה מבדלת בין דיכאון אנדוגני להשתטות הזקנה באוכלוסית הקשישים

Senile Dementia is regarded as one of the main medical and social problems accompaning the aging process. Over 15% of the elderly, aged 65 and over are afflicted by this disease. Often the symptoms of dementia overlap those accompaning depressive disorders. One of the most frequent and difficult problems facing the physician is to properly differentiate between those suffering from dementia and/or reversible cognitive disorders, mainly depression. Sleeping Disorders, lack of appetite and weight loss are the most prominent symptoms of the elderly suffering from depression, and are the manifestation of the Limbic-Hypothalamic-Pituitary axis dysfunction. Significant abnormalities in the secretion of cortisol, h.G.H. and T.S.H. in response to dynamic tests were found in patients suffering from depression and reinforced the assumption of the existence of significant hypothalmic disorders in those patients. In the search for additional parameters to differentiate between dementia and depressive disorders, Dexamethasone suppresion test (D.S.T.) was performed in 81 aged patients (49 females and 32 males). The correlation was checked between the results of the D.S.T., the psychiatric evaluation for depression and the diagnosis of dementia, as cited by the reffering physician. From among 48 elderly patients diagnosed as suffering from dementia, 15 (31.8%) who acconding to psychiatric evaluation results using the Hamilton and Raskin scales and the D.S.T. results, were found to be suffering from depression. Four patients (12%) from among 33 aged who were known not to be suffering from dementia, were found to have depressive disorders based upon the above parameters. The staistical analysis indicated ability of 67%–100% and positive predictive value (P.V.) of 71%–100% of the D.S.T. regarding depression in the different groups. This is in accordance with results found in other research publications. The D.S.T. is an important laboratory aid that together with an accurate clinical evaluation, helping the diagnosis of depressive disorders among the aged thus enabling these patients to receive proper treatment.