I. Heuser et al., THE COMBINED DEXAMETHASONE CRH TEST - A REFINED LABORATORY TEST FOR PSYCHIATRIC-DISORDERS, Journal of Psychiatric Research, 28(4), 1994, pp. 341-356
This report summarizes our extensive experience with the application o
f the DEX/CRH test to assess hypothalamic-pituitary-adrenal-system (HP
A) alteration in patients with psychiatric disorders. The application
of this combined dexamethasone suppression/CRH-challenge (DEX/CRH) tes
t requires individuals to take 1.5 mg dexamethasone (DEX) at 23:00 h o
rally the previous night. On the day of the test, 100 mu g human CRH a
re administered to the subjects under study at 15:00 h intravenously a
s a bolus, and blood samples for the determination of plasma cortisol
and ACTH are drawn every 15 min from 14:00 h to 18:00 h. DEX/CRH-test
results from 96 patients with major depression (MDE), 11 with a manic
episode (MA), 9 with panic disorder (PD), 24 with a schizophrenic psyc
hosis (SP), and 82 healthy control subjects served as the data base fo
r this report. Three major conclusions can be drawn from statistical a
nalysis of these data: 1. Psychiatric patients (n = 140), regardless o
f diagnostic classification, release significantly more cortisol and A
CTH after DEX and additional CRH in comparison with age-matched contro
ls. This hormonal release pattern (DEX/CRH-test phenomenon) supports t
he assumption that psychiatric patients are prone to an altered glucoc
orticoid feedback regulation during the acute illness episode. This su
pports the notion that the DEX/CRH-test phenomenon constitutes a neuro
endocrine sign of these various disorders and emphasizes the usefulnes
s of the DEX/CRH test as a laboratory test to monitor the course of th
ese disorders. 2. The sensitivity of the DEX/CRH test for MDE (about 8
0%) greatly exceeds that of the standard DST (1-2 mg of DEX), which ha
s been reported to average about 44% in a meta-analysis of the literat
ure data; in our sample the sensitivity of the DST was about 25%. 3. T
he sensitivity of the DEX/CRH test can be further increased to above 9
0% if subjects are clustered into four different age ranges: age < 35
years, age between 35 and 50 years, age between 50 and 70 years, and a
ge above 70 years. 4. By reducing the time points of blood sampling fo
r ACTH and cortisol to as few as five (15:00, 15:30, 15:45, 16:00, and
16:15 h), the DEX/CRH-test procedure becomes more convenient and more
easily applicable without reducing its sensitivity.