Dexamethasone suppression in depressed elderly outpatients.

Area of Science:

• Geriatric Psychiatry
• Neuroendocrinology
• Mood Disorders

Background:

• The dexamethasone suppression test (DST) is a diagnostic tool used in evaluating major depressive disorder (MDD).
• Previous studies suggested a higher rate of positive DSTs in patients with melancholic depression.
• The utility of DST in elderly, unipolar, treatment-naive MDD patients requires further investigation.

Purpose of the Study:

• To assess the prevalence and significance of positive DST results in older adults (over 60) with unipolar major affective disorder.
• To determine if DST positivity correlates with depression severity, melancholic features, or other clinical variables in this population.
• To evaluate the relevance of DST findings for guiding specific treatment decisions in elderly MDD patients.

Main Methods:

• A cohort of 85 previously untreated outpatients over age 60 with unipolar major depressive disorder were evaluated.
• Patients underwent a systematic structured interview (NIMH-DIS) and scored over 20 on the Hamilton Depression Rating Scale (HAM-D).
• The dexamethasone suppression test (DST) was administered, and serum cortisol levels were monitored following dexamethasone challenge.

Main Results:

• Only 14% (12 of 85) of patients exhibited positive DST results.
• A higher, though not statistically significant (p < .10), rate of positive DSTs was observed in non-melancholic (24%) compared to melancholic (10%) patients.
• DST results did not correlate with HAM-D scores, Zung depression scores, gender, or treatment response.

Conclusions:

• Positive DST results appear less common in older adults with major depressive disorder than previously reported.
• DST positivity does not seem to be associated with greater depression severity or specific clinical features in this age group.
• The findings suggest that the DST may have limited relevance for treatment indications in elderly patients with unipolar depression.