Hunt G E, O'Sullivan B T, Johnson G F, Caterson I D
Department of Psychiatry, University of Sydney, N.S.W., Australia.
Psychiatry Res. 1991 Feb;36(2):209-22. doi: 10.1016/0165-1781(91)90132-9.
The aim of this study was to examine cortisol dynamics over a range of plasma dexamethasone (DEX) levels using a two-dose dexamethasone suppression test (DST). Two doses of DEX (0.5 and 1.5 mg) were administered in a randomized crossover design to 29 inpatients with major depression and 26 controls to identify the upper range of plasma DEX levels that would allow reliable interpretation of DST results. It was hypothesized that due to inappropriately high plasma DEX levels following 1.5 mg, several depressed patients would switch from suppressors after the 1.5 mg dose to nonsuppressors after 0.5 mg. In contrast, the nondepressed controls with high DEX levels following 1.5 mg would remain suppressors after the lower dose. Fourteen patients were identified as having high 4 p.m. DEX levels (greater than 4 nmol/l) after the 1.5 mg DST. Cortisol was suppressed in all of the subjects with high DEX levels. After 0.5 mg, five of the eight depressed patients with high DEX levels switched to nonsuppressors. In contrast, all six controls with high DEX levels remained suppressors. These results indicate that patients with high DEX levels after a 1 mg DST should be retested with a lower dose. This strategy enhances the sensitivity of the DST without loss of specificity.
本研究的目的是使用两剂量地塞米松抑制试验（DST）来检测一系列血浆地塞米松（DEX）水平下的皮质醇动态变化。以随机交叉设计对29名重度抑郁症住院患者和26名对照者给予两剂量的DEX（0.5毫克和1.5毫克），以确定能够可靠解读DST结果的血浆DEX水平上限。研究假设，由于1.5毫克剂量后血浆DEX水平过高，部分抑郁症患者会从1.5毫克剂量后的抑制者转变为0.5毫克剂量后的非抑制者。相比之下，1.5毫克剂量后DEX水平高的非抑郁症对照者在较低剂量后仍为抑制者。14名患者在1.5毫克DST后被确定为下午4点时DEX水平高（大于4纳摩尔/升）。所有DEX水平高的受试者的皮质醇均被抑制。0.5毫克剂量后，8名DEX水平高的抑郁症患者中有5名转变为非抑制者。相比之下，所有6名DEX水平高的对照者仍为抑制者。这些结果表明，1毫克DST后DEX水平高的患者应以较低剂量重新检测。该策略可提高DST的敏感性且不损失特异性。
