Dexamethasone suppression test and response to antidepressant therapy in psychogeriatric patients

Dexamethasone suppression test in mentally handicapped subjects

Objective:This study investigated the frequency of abnormal Dexamethasone Suppression Test (DST) in a randomly selected group of mentally handicapped subjects.Method:Forty three subjects living in the community were selected and assessed on a variety of clinical rating scales including Hamilton Rating Scale for Depression (HDS) and Wessex Case Register Form (WCRF). DST was conducted on all the patients and the findings correlated with demographic and clinical variables. Groups defined by DST status were also compared using t-test. In subjects who showed an abnormal response, clinical assessments and DST was repeated after 3 months.Results:Only 7 of 43 subjects showed an abnormal response which did not correlate with either the severity of affective symptoms or the presence or absence of behavioural difficulties. Six of the 7 DST positive subjects were either severely or profoundly impaired on DSM-III criteria indicating that the underlying brain pathology may be pathogenetically important. This was supported by the observation that abnormal DST response was enduring at follow up.Conclusions:The findings suggest that DST may be of little value as a diagnostic tool in the mentally handicapped.

The dexamethasone suppression test in dementia: a review of the literature

To examine the utility of the dexamethasone suppression test (DST) in the differential diagnosis of depression in elderly demented patients, we reviewed the literature and focused on four components of this question: (1) cortisol nonsuppression rates in dementia; (2) cortisol nonsuppression and dementia severity; (3) cortisol nonsuppression in demented versus depressed patients; and (4) cortisol nonsuppression following antidepressant treatment. A combined analysis of 27 articles showed cortisol nonsuppression in 60% of patients with concurrent dementia and depression, in 47% of patients with depression only, in 41% of patients with dementia only, in 46% of patients with multi-infarct dementia, in 36% of patients with primary degenerative dementia, and in 10% of controls. The abnormal DST rate in demented patients was not significantly different from the abnormal DST rate in depressed patients. Eight of 12 studies (67%) did not find a significant relationship between DST results and dementia severity dementia patients without depression. Twelve of 13 studies (92%) did not find a relationship between age and DST outcome. The data we reviewed do not support the use of the DST in discriminating between depression and dementia or between dementia subtypes.

Dexamethasone suppression test in dementia and depression. Clinical and biological correlates

To determine the usefulness of the DST in differentiating depression from dementia, the test was administered to three diagnostic groups of psychogeriatric patients: depression; dementia; and dementia with depression. Clinical assessments were supplemented by ratings on the HRSD and SCAG, as well as by EEG and CT. All three groups showed a high incidence of abnormal DST results unrelated to presence or severity of affective symptoms, but showing a better association with SCAG and its 'organic' subsets. The mechanism(s) underlying these abnormal results may reflect organic brain disease. The usefulness of the DST in differentiating depression from dementia in the elderly was not confirmed.