- Email: [email protected]
CRH test: a study in healthy subjects
Journal of Psychiatric Research 35 (2001) 95–104 www.elsevier.com/locate/jpsychires
Psychological, autonomic and neuroendocrine responses to acute stressors in the combined dexamethasone/CRH test: a study in healthy subjects Akihiko Oshima a,b, Hideichi Miyano c, Saori Yamashita a, Toshimi Owashi a, Shinichi Suzuki d, Yuji Sakano c, Teruhiko Higuchi e,* a Department of Neuropsychiatry, Showa University Fujigaoka Hospital, Yokohama, Japan Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, USA c Department of Health Sciences, Waseda University School of Human Sciences, Saitama, Japan d Faculty of Health and Welfare Science, Okayama Prefectural University, Okayama, Japan e National Center of Neurology and Psychiatry Kohnodai Hospital, 1-7-1 Kohnodai, Ichikawa, Chiba 272-8516, Japan b
Received 23 June 2000; received in revised form 8 February 2001; accepted 14 February 2001
Abstract The combined dexamethasone/CRH test (DEX/CRH test) is reported to produce augmented ACTH and cortisol responses in various psychiatric disorders as well as in some non-psychiatric conditions. To examine whether stress affects the outcome of DEX/ CRH test, two stress groups in a repeated measures design were compared to an age-matched control group with regard to the psychological, autonomic and neuroendocrine responses after the combined dexamethasone and CRH challenge. Cold pressor (4 C, total 10 min) produced stronger subjective distress than mental arithmetic (15 min). Cold exposure, but not the mental test, elevated systolic and diastolic blood pressure, whereas the mental test increased pulse rate and skin conductance level more markedly than cold exposure. Neither stressor produced a significantly enhanced response of ACTH and cortisol in DEX/CRH test, and there was no correlation between psychological and neuroendocrine responses. These findings suggest that different stressors induce different patterns of sympathetic activation and that acute stress is unlikely to affect the results of DEX/CRH test. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Cold pressor; Mental arithmetic; Hypothalamic-pituitary-adrenal axis; Sympathetic nervous system
1. Introduction The hypothalamic-pituitary-adrenal (HPA) axis is activated by stress as well as in depression. Carroll et al. (1981) reported that nonsuppression in the dexamethasone suppression test (DST) is common among the patients with melancholia. A vast number of studies have since been conducted to replicate this finding, and have established that the sensitivity of DST to major depression is no more than 40–50% (Arana et al., 1985). In this context, Holsboer et al. (1987) serially performed on cases with major depressive episode the corticotropin-releasing hormone (CRH) challenge after pretreatment with dexamethasone (DEX), and found * Corresponding author. Tel.: +81-47-372-3501; fax: +81-47-3754775. E-mail address: [email protected] (T. Higuchi).
that the hyperresponses of ACTH and cortisol during the episode were normalized with recovery. This phenomenon was confirmed in a large-scaled study by Holsboer-Trachsler et al. (1991). Heuser et al. (1994) concluded that the sensitivity of this combined DEX/ CRH test to major depression is over 80%, which far exceeds that of the standard DST. The test also reportedly predicts medium-term outcome in patients with remitted depression. (Zobel et al., 1999). The DEX/CRH test, however, has also been shown to produce enhanced cortisol responses in elderly endurance athletes (Heuser et al., 1991), healthy subjects at high familial risk for affective disorders (Holsboer et al., 1995), mania (Schmider et al., 1995), schizophrenia (Lammers et al., 1995), and multiple sclerosis (Grasser et al., 1995). These rather nonspecific findings raise a possibility that mental and physical stress experienced during illness, rather than each illness itself, may con-
0022-3956/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0022-3956(01)00010-3
96
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
tribute to the test results. Although there have been some studies with mixed results on the effect of stress on the DST status of healthy subjects (Ceulemans et al., 1985; Bendarka and Wong, 1995) and of depressed patients (Frecska et al., 1988; Bloudin et al., 1992), there is yet no published study on the effect of stress on the outcome of DEX/CRH test. Recent studies on the stress-induced expression of immediate early genes in the brain of experimental animals have demonstrated that regions of the brain respond differently to different acute stressors (Senba and Ueyama, 1997). Herman and Cullinan (1997) proposed two different categories of stressors which are processed in different neuronal circuits: those involving an immediate physiologic threat (‘systemic’ stressors) and those requiring interpretation by higher brain structures (‘processive’ stressors). In view of all this, we planned our present study to determine the effect of two categorically different stressors, cold pressor (CP) and mental arithmetic (MA), on the outcome of DEX/CRH test in healthy subject. We simultaneously measured the psychological and autonomic responses to quantify the subjective and objective responses to these stressors, and to investigate their relationship to the results of DEX/ CRH test.
2. Subjects and methods 2.1. Subjects Eight healthy male volunteers (age 21.0 1.6 years) and eight age-matched males (age 22.3 4.3 years) participated in the stress paradigm and the non-stressed control condition, respectively. All the participants were the students of Waseda University except for one staff member of the University and one staff member of Showa University Fujigaoka Hospital. Exclusion criteria were the history of chronic illnesses and mental disorders. Subjects were prohibited from smoking, alcohol intake, and severe exercise since the day prior to the experiment, and the compliance was confirmed with written questionnaires. They also submitted written consent before participation, in accordance with the stipulation of the Ethical Committee of Waseda University School of Human Sciences, which approved the present study. 2.2. Stress paradigms 2.2.1. Cold pressor A bucket of water cooled down to 4 C was used. The subject was told to soak his right foot up to an ankle in the water for 2 min and then put it out for 1 min. This was repeated five times for 15 min.
2.2.2. Mental arithmetic. Four random numbers were shown by a slide projector. The subject had to combine the numbers using basic arithmetic operations (i.d. add, subtract, multiply and divide) to yield 10 (e.g. 3+6+2 1=10). He was instructed that he had only 20 s to complete the task, which was repeated at 20-s intervals for 15 min. 2.3. Procedure Two stressors were randomly assigned to the subjects of the stress group. Each subject participated in the two stress paradigms at the interval of 1 week or more. Testing was carried out in a sound-proof, temperaturecontrolled, brightly lit room. Subjects were seated on a sofa with a PC screen in front of them. The experimenter in an adjacent room operated the equipment for psychological and physiological recordings. A video camera and a monitor were used for continuous observation of the subjects. The subject and experimenter could communicate through an intercom. Time course of the experiment was outlined in Fig. 1. Laboratory testing was started between 12:00 and 18:00, when the circadian rhythm of ACTH and cortisol secretion is stably low. The subject had an oral intake of 1.0 mg dexamethasone (Ban-yu, Japan) 16 h prior to the administration of CRH. On the day of experiment, a questionnaire on health status and drug compliance was filled out, and a pulse and blood-pressure cuff as well as a sensor for skin temperature and conductance were attached for continuous recording. Also, a heparinized cannula was inserted into a forearm vein of the right arm to allow for repeated blood draws. Immediately, the first blood draw (pre) was taken and then 100 mg of human CRH (Mitsubishi, Japan) dissolved into 1.0 ml of physiological saline was administered intravenously. Then, a psychological questionnaire was shown on the PC screen and the subject answered it with a mouse. Fifteen minutes later, the second blood draw (0 min) and psychological testing (BASE) were carried out, and the subject of the stress groups was immediately given one of the stressors. The third blood draw (15 min) was taken 15 min after the second. Upon the termination of stressor, the subject answered the psychological questionnaire (TASK) again and was allowed to relax for 15 min. The fourth blood draw (30 min) was obtained in the meantime and, after the relaxation was over, the subject answered the psychological questionnaire (POST-1) and the sensor and the blood pressure cuff were detached. The subject then walked to a separate calm room, where he lay on bed alone throughout the rest of experiment. There the fifth (45 min), the sixth (60 min), and the seventh (120 min) blood draws were obtained. The experimenters occasionally visited the room to observe the subject, who was instructed not to fall asleep. After the last blood draw, the
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 1. Time course of the experiment. The subjects answered a psychological test at
cannula was removed. Finally, the subject filled out the psychological questionnaire (POST-2) and received the payment. 2.4. Measurements Psychological testing was conducted using the mood inventory created and validated by Sakano et al. (1994). It consists of 40 items with five factors: depressive mood (e.g. I feel depressed), tension and excitement (e.g. I feel excited), refreshing mood (e.g. I feel calm and peaceful), anxious mood (e.g. I worry about the future) and fatigue (e.g. I don’t feel like doing anything). Items were rated on a five-point scale, with the two extremes labeled as completely agree and completely disagree. Pulse rate (PR, beat/min) and blood pressure were measured at the left finger using the Finapres method, which allows for continuous beat-to-beat registration of systolic (SBP, mmHg) and diastolic (DBP, mmHg) blood pressure. Skin surface temperature (SST, C) and skin conductance level (SCL, mS) were also measured at the left fingers using a sensor. These data were recorded with a personal computer NEC-PC9801. Blood samples for hormonal analysis (7 ml) were collected in tubes containing 14 mg EDTA-2K. The samples were cooled in iced water and centrifugated (10 min at 3000 rpm at 4 C) at the end of each experiment. Plasma samples were stored at 20 C and assayed within 10 days. ACTH (pg/ml) and cortisol (mg/dl) concentrations were determined by immunoradiometric assay and radioimmunoassay at Otsuka Assay Laboratories, Otsuka Pharmaceutical Co. Ltd., Japan. The intra-assay coefficients of variation for ACTH assay were 4.4 and 1.4% at the mean concentration of
97
15 min (#) for practice, but the data were not used for ana-
43.7 and 107.5 pg/ml, respectively. The inter-assay coefficients of variation for ACTH were 8.8 and 3.4% at the mean concentration of 42.5 and 106.0 pg/ml, respectively. The intra-assay coefficients of variation for cortisol were 20.0 and 11.6% at the mean concentration of 4.00 and 11.03 mg/dl, respectively. The inter-assay coefficients of variation were 2.5 and 2.6% at the mean concentration of 5.63 and 13.56 mg/dl, respectively. The detection limit of ACTH and cortisol assays was 4.0 pg/ ml and 1.0 mg/dl, respectively.
2.5. Statistical analysis All data were subjected to statistical analysis after baseline subtraction. Mean PR, SBP, DBP, SST, and SCL were calculated for each of the five registration periods: the 3-min registration at baseline (for 3 min till the second blood draw), the 3-min registrations during 0–3 min (TASK-1), 6–9 min (TASK-2), and 12–15 min (TASK-3) after the initiation of stressor, and the 3-min registration during recovery (POST; 3 min till the fourth blood draw) after the termination of stressor. Values for PR, SBP and DBP underwent Z-transformation [(measured value — mean value at baseline)/standard deviation at baseline], and values for SCL square root transformation. The response during each registration period was defined as the mean value during the given period minus the mean value during the baseline period. Likewise, the hormonal and psychological responses, for which raw values were used, were as the mean value at each measurement point minus the mean value at the baseline (‘pre’ for hormones and ‘BASE’ for psychological testing).
98
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 2. (a) Variations in the mean depressed mood score after stress. & Mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK > POST-1**, POST-2**. TASK: CP < control**. **P< 0.01. (b) Variations in the mean tension and excitement score after stress. & mental arithmetic (MA); & cold pressor (CP); * control. CP: TASK > POST-1**, POST-2**. TASK: CP > MA*, control**. *P<0.05; **P<0.01. (c) Variations in the mean refreshing mood score after stress. & Mental arithmetic (MA); ^ cold pressor (CP); * control. MA: TASK**, POST-1** > POST-2. CP: TASK**, POST-1** > POST-2. **P <0.01.
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Main effects of group and time and their interaction were analyzed by means of two-way ANOVA followed by Tukey’s HSD test, using the STATISTICA software release 4.1 J. Correlations between hormonal responses (15 min) and mental status (TASK) as well as autonomic responses (POST) were analyzed by Spearman’s rank correlation coefficient, using StatView version 5.0. The level of significance was defined as 5%. Standard errors of the mean at measurement points are expressed by error bars in the graphs.
99
3. Results 3.1. Subjective reports of mental status For depressive mood there was a significant time effect [F(2, 42)=5.42, P=0.008] and a significant grouptime interaction [F(4, 42)=4.85, P=0.003], without any significant group effect. The depression score in the CP group, which was significantly higher only at TASK than in the control group, significantly
Fig. 3. (a) Variations in the mean pulse rate after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. MA: TASK-1**, TASK-2** > POST; TASK-1 > TASK-3*. CP: TASK-1**, TASK-2**, TASK-3** > POST. TASK-1**, TASK-2**, TASK-3*: MA>control. *P<0.05; **P< 0.01. (b) Variations in the mean systolic blood pressure after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK-1 < TASK-2**, TASK-3**. TASK-2**, TASK-3*: CP > control. POST: CP > MA**. *P<0.05; **P <0.01. (c) Variations in the mean diastolic blood pressure after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK-1 control*. TASK-2: CP < control**. *P<0.05; **P <0.01. (d) Variations in the mean skin conductance level after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. MA: TASK-1 > POST**. CP: TASK-1 < TASK-3**, POST**. Control: TASK-1 > TASK-2**, TASK-3**, POST**. TASK-2, TASK-3: MA > control**, CP**. **P< 0.01. (continued on next page)
100
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 3. (continued).
decreased at POST-1 and remained at the same level at POST-2 (Fig. 2a). The same score for the MA group was identical to that of the controls at any point examined (Fig. 2a). For tension and excitement there was a significant time effect [F(2, 42)=18.77, P=0.000], a significant grouptime interaction [F(4, 42)=5.49, P=0.001], but no significant group effect. The same score in the CP group was significantly higher at TASK than in the MA group and in the controls, significantly decreased at POST-1, and remained at the same level at POST-2 (Fig. 2b). For refreshing mood, there was a significant time effect [F(2, 42)=36.29, P=0.000] as well as a significant grouptime interaction [F(4, 42)=2.9, P=0.032], but no significant group effect. In both the CP and MA groups, whose scores were identical to those of controls at any measurement point, the same score significantly dropped at POST-2 compared to both TASK and POST-1 (Fig. 2c). For anxious mood
and fatigue, none of the group effect, time effect and their interaction were significant. 3.2. Autonomic variables For PR there was a significant time effect [F(3, 63)=33.83, P=0.000] as well as a significant grouptime interaction [F(6, 63)=3.70, P=0.003], without any significant group effect. In both the MA and CP groups, PR was significantly higher at TASK-1 compared to the controls, and significantly decreased with time (Fig. 3a). The PR in the MA group remained higher at TASK-2 and 3 than in controls (Fig. 3a). For SBP there was a significant time effect [F(3, 63)=8.84, P=0.000] and a significant grouptime interaction [F(6, 63)=3.42, P=0.005], but no significant group effect. In the CP group, SBP was elevated at TASK-2 and 3 compared to TASK-1, and also remained higher
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
101
Fig. 4. (a) Variations in the mean plasma ACTH concentration after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. (b) Variations in the mean plasma cortisol concentration after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control.
than in controls at TASK-2, 3, and POST (Fig. 3b). In the MA group there was no significant change in time course and in comparison to controls (Fig. 3b). For DBP there was a significant time effect [F(3, 63)=9.98, P=0.000] and a significant grouptime interaction [F(6, 63)=3.53, P=0.004], but no significant group effect. Similar to SBP, CP elevated the SBP at TASK-2 and 3, although the value was higher than in the controls only at TASK-2 (Fig. 3c). MA failed to produce any change in DBP, except for the significantly higher value at TASK-1 compared to controls (Fig. 3c). For SCL there was a significant group effect [F(2, 21)=3.80, P=0.039], a significant time effect [F(3, 63)=22.17, P=0.000], and a significant grouptime interaction [F(6, 63)=2.32, P=0.044]. In all three
groups, SCL significantly decreased with time, although to different degrees (Fig. 3d). The value in the MA group was significantly higher than in the controls and in the CP group at TASK-2 and 3 (Fig. 3d). For SST there was a significant time effect [F(3, 63)=10.03, P=0.000] but neither significant group effect nor grouptime interaction. SST tended to decrease with time (data not shown). 3.3. Neuroendocrine variables For ACTH there was a significant time effect [F(5, 105)=9.59, P=0.000], but neither significant group effect nor grouptime interaction. For cortisol as well, there was a significant time effect [F(5, 105)=20.91,
102
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
P=0.000] but neither significant group effect nor grouptime interaction. The plasma concentration of both hormones tended to be elevated during the period between 15 min and 60 min (Fig. 4a, b). 3.4. Correlations between neuroendocrine vs psychological and autonomic responses When the data of the CP, MA, and controls groups were combined, no significant correlation was found between mental status and ACTH as well as cortisol response upon cessation of stressors. PR was positively correlated with ACTH (rho=0.439, P=0.036) as well as cortisol (rho=0.422, P=0.043) response. SBP was positively correlated with cortisol response (rho=0.413, P=0.048), but not with ACTH response. DBP, SCL, and SST were not significantly correlated with either hormone. There was a strong positive correlation between ACTH and cortisol responses (rho=0.825, P=0.000).
4. Discussion The main finding of the current study indicates that the DEX/CRH test outcome is not confounded by a variety of acute stressors. Below, we will discuss the results with respect to each parameter examined. 4.1. Psychological responses In the present study, psychological testing revealed that CP significantly increased the scores for depressive mood and tension and excitement, which decreased to the normal levels during the recovery period, but MA failed to produce significant changes in these two scores. In our paradigm, CP may be a subjectively stronger stressor than MA. Neither stressor significantly altered the scores of refreshing mood, anxious mood, and fatigue, though the motivation score did drop with time in both stressors. This indicates that the scores of depression and tension and excitement may be the most sensitive indicators of subjective stress. 4.2. Autonomic responses For autonomic responses, CP significantly elavated PR at one registration period, SBP at two, DBP at one, but not SCL at any. PR and SCL decreased, and SBP and DBP increased with time. In contrast, MA caused the significant increase in PR at three registration periods and SCL at two, but not in SBP and DBP. Similarly to CP, PR and SCL declined with time in MA as well, although SBP and DBP remained at statistically identical levels. These results are in line with the report (Anderson et al., 1987) that MA sympathetic responses
to a stressor vary depending on the area of sympathetic innervation. The mechanism remains unclear as to how different stressors lead to different patterns of sympathetic activation. LeBlanc et al. (1979) showed that MA produced a greater increase of epinephrine than CP, while the effect of CP was greater on norepinephrine than MA. Ward et al. (1983) also demonstrated that epinephrine showed a greater increase to MA than to all the other stressors including CP. In this study, the norepinephrine response was not significantly different between CP and MA. As epinephrine mainly derives from the adrenal medulla and norepinephrine from the sympathetic nervous system, MA may activate the sympathetic-adrenal system more than CP. The different patterns in sympathetic activation may be associated with the different neuronal circuits of brain which process the stress response. ‘Systemic’ stressors are relayed directly to the paraventricular nucleus (PVN), probably via brainstem catecholaminergic projections, whereas ‘processive’ stressors appear to be channeled through limbic forebrain circuits which connect with PVN via interactions with GABA-containing neurons in the bed nucleus of stria terminalis, preoptic area, and hypothalamus (Herman and Cullinan, 1997). CP and MA correspond to ‘systemic’ and ‘processive’ stressors, respectively, and would be differentially processed in the central nervous system. Further elucidation requires information on regional brain responses to each stressor as obtained by functional brain imaging. 4.3. Neuroendocrine responses The post-DEX/CRH ACTH and cortisol responses to both CP and MA were statistically identical to those in the controls. Also, there was no significant correlation between the hormonal and psychological responses. These findings suggest that acute stress hardly affects the results of DEX/CRH test. In the past reports, the cortisol level after systemic cold exposure was increased (Wilson et al., 1970; Hiramatsu et al., 1984; Wagner et al., 1987), decreased (Golstein-Golaire et al., 1970; Leppa¨luoto et al., 1988) or unchanged (Ohno et al., 1987). Local cold pressor as used in the present study produced an enhanced cortisol response (Hiramatsu et al., 1984; Berger et al., 1987). After MA, cortisol was increased (Berger et al., 1987; Jørgensen et al., 1990) or unchanged (Cacioppo et al., 1995). These inconsistent results may reflect the differences in experimental paradigm as well as the subtlety of hormonal responses. Thus, in the DEX/CRH test, the effects of exogenous DEX and CRH may override the subtle alterations in HPA axis fuctions caused by stressors. We had to modify the original time course of DEX/ CRH test (Holsboer et al., 1987; Holsboer-Trachsler
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
et al., 1991) for administrative reasons. Our justification is (1) that the basal ACTH and cortisol secretions are stably low in the afternoon, when our testing was done, and (2) that the ACTH and cortisol responses to the DEX/CRH administration are nearly flat in normal subjects between 14:00 and 18:00 with the original method (e.g. Heuser et al., 1991; Holsboer-Trachsler et al., 1991; Holsboer et al., 1995). Also, we used 1.0 mg of DEX instead of the original 1.5 mg because Japanese subjects have been reported to be more susceptible to DEX suppression in DST (WHO, 1987). This dose of DEX was sufficient to produce an elevated ACTH response to the DEX/CRH test in patients with major depression (Oshima et al., 2000). As a putative mechanism underlying the ACTH and cortisol hyperresponses in combined DEX/CRH test in depressed subjects, Modell et al. (1997) have referred to the decreased function of glucocorticoid receptors (GR) regulating the vasopressin expression in the paraventricular nucleus. An escape from the GR-mediated negative feedback would result in an augmented function of vasopressin in this region, which indeed was demonstrated by Raadsheer et al. (1994) and Purba et al. (1996) using post-mortem brains of depressed patients. Our negative results in healthy volunteers may be partly explained by the lack of GR downregulation and of the resultant vasopressin hypersecretion at the level of paraventricular nucleus with the use of the short stressors that we applied. Variable correlations between hormonal and autonomic responses may be explained by the complexity of interactions regulating these two systems as well as by the above-mentioned regional variation of peripheral sympathetic responses. Again, topographical information on the brain response to stress is required for further clarification. The strong positive correlation between ACTH and cortisol responses indicates that the HPA axis function was intact in the subjects. Although the small size of the present study prevents us from drawing a definite conclusion, our data suggest that acute stress is unlikely to affect the outcome of DEX/CRH test. Therefore, augmented cortisol responses to the DEX/CRH test seen in various mental illnesses may reflect the intrinsic pathophysiology of each illness rather than stress per se.
Acknowledgements We thank Dr. Atsufumi Iida and Dr. Gerald Vogt of Emory University, Dr. Astrid C. E. Linthorst and Dr. Ayako Yamamoto of Max Planck Institute of Psychiatry, and Dr. Masahiko Mikuni of Gunma University for their warm support and helpful suggestions, and Ms. Mikie Okazaki for her excellent secretarial assistance. This study was partly supported by Health
103
Sciences Research Grants (Research on Brain Science) from the Ministry of Health and Welfare, Japan.
References Anderson EA, Wallin BG, Mark AL. Dissociation of sympathetic nerve activity in arm and leg muscle during mental stress. Hypertension 1987;9(suppl III]):III–114-III-119. Arana GW, Baldessarini RJ, Ornsteen. The dexamethasone suppression test for diagnosis and prognosis in psychiatry — commentary and review. Arch Gen Psychiatry 1985;42:1193–204. Bendarka MM, Wong GA. Effect of the stress of medical residency training on the overnight dexamethasone suppression test. Horm Metab Res 1995;27:332–4. Berger M, Bossert S, Krieg J-C, Dirlich G, Ettmeier W, Schreiber W, et al. Interindividual differences in the susceptibility of the cortisol system: an important factor for the degree of hypercortisolism in stress situations? Biol Psychiatry 1987;22:1327–39. Blouin J, Spindler E, Perez E, Blouin A, Hotz S, Hakkaku J. The role of stress in interpreting the dexamethasone suppression test. Can J Psychiatry 1992;37:724–7. Cacioppo JT, Malarkey WB, Kiecolt-Glaser JK, Uchino BN, SgoutasEmch SA, Sheridan JF, et al. Heterogeneity in neuroendocrine and immune responses to brief psychological stressors as a function of autonomic cardiac activation. Psychosom Med 1995;57:154–64. Carroll BJ, Feinberg M, Greden JF, Tarika J, Albala AA, Haskett RF, et al. A specific laboratory test for the diagnosis of melancholia — standarzation, validation, and clinical utility. Arch Gen Psychiatry 1981;38:15–22. Ceulemans DLS, Westenberg HGM, van Praag HM. The effect of stress on the dexamethasone suppression test. Psychiatry Res 1985;14:189–95. Frecska E, Luka´cs H, Arato´ M, Mo´d L, Alfo¨ldi A, Magyar I. Dexamethasone suppression test and coping behavior in psychosocial stress. Psychiatry Res 1988;23:137–45. Golstein-Golaire J, Vanhaelst L, Bruno OD, Leclercq R, Copinschi G. Acute effects of cold on blood levels of growth hormone, cortisol, and thyrotropin in man. J Appl Physiol 1970;29:622–6. Grasser A, Mo¨ller A, Backmund H, Yassouridis A, Holsboer F. Heterogeneity of hypothalamic-pituitary-adrenal system response to a combined dexamethasone-CRH test in multiple sclerosis. Exp Clin Endocrinol 1996;104:31–7. Herman JP, Cullinan WE. Neurocircuitry of stress: central control of the hypothalamo-pituitary-adrenocortical axis. Trends Neurosci 1997;20:78–84. Heuser IJE, Wark H-J, Keul J, Holsboer F. Hypothalamic-pituitaryadrenal axis function in elderly endurance athletes. J Clin Endocrinol Metab 1991;73:485–8. Heuser I, Yassouridis A, Holsboer F. The combined dexamethasone/ CRH test: a refined laboratory test for psychiatric disorders. J Psychiat Res 1994;28:341–56. Hiramatsu K, Yamada T, Katakura M. Acute effects of cold on blood pressure, renin-angiotensin-aldosterone system, catecholamines and adrenal steroids in man. Clin Exp Pharm Physiol 1984;11:171–9. Holsboer F, von Bardeleben U, Wiedemann K, Mu¨ller OA, Stalla GK. Serial assessment of corticotropin-releasing hormone response after dexamethasone in depression — implications for pathophysiology of DST nonsuppression. Biol Psychiatry 1987;22:228–34. Holsboer F, Lauer CJ, Schreiber W, Krieg J-C. Altered hypothalamicpituitary-adrenocortical regulation in healthy subjects at high familial risk for affective disorders. Neuroendocrinology 1995;62:340–7. Holsboer-Trachsler E, Stohler R, Hatzinger M. Repeated administration of the combined dexamethasone-human corticotropin releasing
104
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
hormone stimulation test during treatment of depression. Psychiatry Res 1991;38:163–71. Jørgensen LS, Christiansen P, Raundahl U, Østgaard S, Christensen NJ, Fenger M, et al. Autonomic response to an experimental psychological stressor in healthy subjects: measurement of sympathetic, parasympathetic, and pituitary-adrenal parameters: test-retest reliability. Scand J Clin Lab Invest 1990;50:823–9. Lammers C-H, Garcia-Borreguero D, Schmider J, Gotthardt U, Dettling M, Holsboer F, et al. Combined dexamethasone/corticotropinreleasing hormone test in patients with schizophrenia and in normal controls: II. Biol Psychiatry 1995;38:803–7. LeBlanc J, Coˆte´ J, Jobin M, Labrie A. Plasma catecholamines and cardiovascular responses to cold and mental activity. J Appl Physiol Respirat Environ Excercise Physiol 1979;47:1207–11. Leppa¨luoto J, Korhonen I, Huttunen P, Hassi J. Serum levels of thyroid and adrenal hormones, testosterone, TSH, LH, GH and prolactin in men after 2-h stay in a cold room. Acta Physiol Scand 1988;132:543–8. Modell S, Yassouridis A, Huber J, Holsboer F. Corticosteroid receptor function is decreased in depressed patients. Neuroendocrinology 1997;65:216–22. Ohno H, Yahata T, Yamashita K, Kuroshima A. Effect of acute cold exposure on ACTH and zinc concentrations in human plasma. Jap J Physiol 1987;37:749–55. Oshima A, Yamashita S, Owashi T, Murata T, Tadokoro C, Miyaoka H, et al. The differential ACTH responses to combined dexamethasone/CRH administration in major depressive and dysthymic disorders. J Psychiat Res 2000;34:325–8. Purba JS, Hoogendijk WJG, Hofman MA, Swaab DF. Increased number of vasopressin- and oxytocin-expressing neurons in the
paraventricular nucleus of the hypothalamus in depression. Arch Gen Psychiatry 1996;53:137–43. Raadsheer FC, Hoogendijk WJG, Stam FC, Tilders FJH, Swaab DF. Increased numbers of corticotropin-releasing hormone expressing neurons in the hypothalamic paraventricular nucleus of depressed patients. Neuroendocrinology 1994;60:436–44. Sakano Y, Fukui T, Kumano H, Horie H, Kawahara K, Yamamoto H, et al. Development and validation of a new mood inventory. Shinshin-Igaku 1994;34:629–36(in Japanese).. Schmider J, Lammers C-H, Gotthardt U, Dettling M, Holsboer F, Heuser IJE. Combined dexamethasone/corticotropin-releasing hormone test in acute and remitted manic patients, in acute depression, and in normal controls: I. Biol Psychiatry 1995;38:797–802. Senba E, Ueyama T. Stress-induced expression of immediate early genes in the brain and peripheral organs of the rat. Neurosci Res 1997;29:183–207. Wagner JA, Horvath SM, Kitagawa K, Bolduan NW. Comparisons of blood and urinary responses to cold exposures in young and older men and women. J Gerontol 1987;42:173–9. Ward MM, Mefford IN, Parker SD, Chesney MA, Taylor CB, Keegan DL, et al. Epinephrine and norepinephrine responses in continuously collected human plasma to a series of stressors. Psychosom Med 1983;45:471–86. Wilson O, Hedner P, Laurell S, Nosslin B, Rerup C, Rosengren E. Thyroid and adrenal response to acute cold exposure in man. J Appl Physiol 1970;28:543–8. World Health Organization. The dexamethasone suppression test in depression: a World Health Organization collaborative study. Br J Psychiatry 1987;150:459–62.
Psychological, autonomic and neuroendocrine responses to acute stressors in the combined dexamethasone/CRH test: a study in healthy subjects Akihiko Oshima a,b, Hideichi Miyano c, Saori Yamashita a, Toshimi Owashi a, Shinichi Suzuki d, Yuji Sakano c, Teruhiko Higuchi e,* a Department of Neuropsychiatry, Showa University Fujigaoka Hospital, Yokohama, Japan Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, USA c Department of Health Sciences, Waseda University School of Human Sciences, Saitama, Japan d Faculty of Health and Welfare Science, Okayama Prefectural University, Okayama, Japan e National Center of Neurology and Psychiatry Kohnodai Hospital, 1-7-1 Kohnodai, Ichikawa, Chiba 272-8516, Japan b
Received 23 June 2000; received in revised form 8 February 2001; accepted 14 February 2001
Abstract The combined dexamethasone/CRH test (DEX/CRH test) is reported to produce augmented ACTH and cortisol responses in various psychiatric disorders as well as in some non-psychiatric conditions. To examine whether stress affects the outcome of DEX/ CRH test, two stress groups in a repeated measures design were compared to an age-matched control group with regard to the psychological, autonomic and neuroendocrine responses after the combined dexamethasone and CRH challenge. Cold pressor (4 C, total 10 min) produced stronger subjective distress than mental arithmetic (15 min). Cold exposure, but not the mental test, elevated systolic and diastolic blood pressure, whereas the mental test increased pulse rate and skin conductance level more markedly than cold exposure. Neither stressor produced a significantly enhanced response of ACTH and cortisol in DEX/CRH test, and there was no correlation between psychological and neuroendocrine responses. These findings suggest that different stressors induce different patterns of sympathetic activation and that acute stress is unlikely to affect the results of DEX/CRH test. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Cold pressor; Mental arithmetic; Hypothalamic-pituitary-adrenal axis; Sympathetic nervous system
1. Introduction The hypothalamic-pituitary-adrenal (HPA) axis is activated by stress as well as in depression. Carroll et al. (1981) reported that nonsuppression in the dexamethasone suppression test (DST) is common among the patients with melancholia. A vast number of studies have since been conducted to replicate this finding, and have established that the sensitivity of DST to major depression is no more than 40–50% (Arana et al., 1985). In this context, Holsboer et al. (1987) serially performed on cases with major depressive episode the corticotropin-releasing hormone (CRH) challenge after pretreatment with dexamethasone (DEX), and found * Corresponding author. Tel.: +81-47-372-3501; fax: +81-47-3754775. E-mail address: [email protected] (T. Higuchi).
that the hyperresponses of ACTH and cortisol during the episode were normalized with recovery. This phenomenon was confirmed in a large-scaled study by Holsboer-Trachsler et al. (1991). Heuser et al. (1994) concluded that the sensitivity of this combined DEX/ CRH test to major depression is over 80%, which far exceeds that of the standard DST. The test also reportedly predicts medium-term outcome in patients with remitted depression. (Zobel et al., 1999). The DEX/CRH test, however, has also been shown to produce enhanced cortisol responses in elderly endurance athletes (Heuser et al., 1991), healthy subjects at high familial risk for affective disorders (Holsboer et al., 1995), mania (Schmider et al., 1995), schizophrenia (Lammers et al., 1995), and multiple sclerosis (Grasser et al., 1995). These rather nonspecific findings raise a possibility that mental and physical stress experienced during illness, rather than each illness itself, may con-
0022-3956/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0022-3956(01)00010-3
96
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
tribute to the test results. Although there have been some studies with mixed results on the effect of stress on the DST status of healthy subjects (Ceulemans et al., 1985; Bendarka and Wong, 1995) and of depressed patients (Frecska et al., 1988; Bloudin et al., 1992), there is yet no published study on the effect of stress on the outcome of DEX/CRH test. Recent studies on the stress-induced expression of immediate early genes in the brain of experimental animals have demonstrated that regions of the brain respond differently to different acute stressors (Senba and Ueyama, 1997). Herman and Cullinan (1997) proposed two different categories of stressors which are processed in different neuronal circuits: those involving an immediate physiologic threat (‘systemic’ stressors) and those requiring interpretation by higher brain structures (‘processive’ stressors). In view of all this, we planned our present study to determine the effect of two categorically different stressors, cold pressor (CP) and mental arithmetic (MA), on the outcome of DEX/CRH test in healthy subject. We simultaneously measured the psychological and autonomic responses to quantify the subjective and objective responses to these stressors, and to investigate their relationship to the results of DEX/ CRH test.
2. Subjects and methods 2.1. Subjects Eight healthy male volunteers (age 21.0 1.6 years) and eight age-matched males (age 22.3 4.3 years) participated in the stress paradigm and the non-stressed control condition, respectively. All the participants were the students of Waseda University except for one staff member of the University and one staff member of Showa University Fujigaoka Hospital. Exclusion criteria were the history of chronic illnesses and mental disorders. Subjects were prohibited from smoking, alcohol intake, and severe exercise since the day prior to the experiment, and the compliance was confirmed with written questionnaires. They also submitted written consent before participation, in accordance with the stipulation of the Ethical Committee of Waseda University School of Human Sciences, which approved the present study. 2.2. Stress paradigms 2.2.1. Cold pressor A bucket of water cooled down to 4 C was used. The subject was told to soak his right foot up to an ankle in the water for 2 min and then put it out for 1 min. This was repeated five times for 15 min.
2.2.2. Mental arithmetic. Four random numbers were shown by a slide projector. The subject had to combine the numbers using basic arithmetic operations (i.d. add, subtract, multiply and divide) to yield 10 (e.g. 3+6+2 1=10). He was instructed that he had only 20 s to complete the task, which was repeated at 20-s intervals for 15 min. 2.3. Procedure Two stressors were randomly assigned to the subjects of the stress group. Each subject participated in the two stress paradigms at the interval of 1 week or more. Testing was carried out in a sound-proof, temperaturecontrolled, brightly lit room. Subjects were seated on a sofa with a PC screen in front of them. The experimenter in an adjacent room operated the equipment for psychological and physiological recordings. A video camera and a monitor were used for continuous observation of the subjects. The subject and experimenter could communicate through an intercom. Time course of the experiment was outlined in Fig. 1. Laboratory testing was started between 12:00 and 18:00, when the circadian rhythm of ACTH and cortisol secretion is stably low. The subject had an oral intake of 1.0 mg dexamethasone (Ban-yu, Japan) 16 h prior to the administration of CRH. On the day of experiment, a questionnaire on health status and drug compliance was filled out, and a pulse and blood-pressure cuff as well as a sensor for skin temperature and conductance were attached for continuous recording. Also, a heparinized cannula was inserted into a forearm vein of the right arm to allow for repeated blood draws. Immediately, the first blood draw (pre) was taken and then 100 mg of human CRH (Mitsubishi, Japan) dissolved into 1.0 ml of physiological saline was administered intravenously. Then, a psychological questionnaire was shown on the PC screen and the subject answered it with a mouse. Fifteen minutes later, the second blood draw (0 min) and psychological testing (BASE) were carried out, and the subject of the stress groups was immediately given one of the stressors. The third blood draw (15 min) was taken 15 min after the second. Upon the termination of stressor, the subject answered the psychological questionnaire (TASK) again and was allowed to relax for 15 min. The fourth blood draw (30 min) was obtained in the meantime and, after the relaxation was over, the subject answered the psychological questionnaire (POST-1) and the sensor and the blood pressure cuff were detached. The subject then walked to a separate calm room, where he lay on bed alone throughout the rest of experiment. There the fifth (45 min), the sixth (60 min), and the seventh (120 min) blood draws were obtained. The experimenters occasionally visited the room to observe the subject, who was instructed not to fall asleep. After the last blood draw, the
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 1. Time course of the experiment. The subjects answered a psychological test at
cannula was removed. Finally, the subject filled out the psychological questionnaire (POST-2) and received the payment. 2.4. Measurements Psychological testing was conducted using the mood inventory created and validated by Sakano et al. (1994). It consists of 40 items with five factors: depressive mood (e.g. I feel depressed), tension and excitement (e.g. I feel excited), refreshing mood (e.g. I feel calm and peaceful), anxious mood (e.g. I worry about the future) and fatigue (e.g. I don’t feel like doing anything). Items were rated on a five-point scale, with the two extremes labeled as completely agree and completely disagree. Pulse rate (PR, beat/min) and blood pressure were measured at the left finger using the Finapres method, which allows for continuous beat-to-beat registration of systolic (SBP, mmHg) and diastolic (DBP, mmHg) blood pressure. Skin surface temperature (SST, C) and skin conductance level (SCL, mS) were also measured at the left fingers using a sensor. These data were recorded with a personal computer NEC-PC9801. Blood samples for hormonal analysis (7 ml) were collected in tubes containing 14 mg EDTA-2K. The samples were cooled in iced water and centrifugated (10 min at 3000 rpm at 4 C) at the end of each experiment. Plasma samples were stored at 20 C and assayed within 10 days. ACTH (pg/ml) and cortisol (mg/dl) concentrations were determined by immunoradiometric assay and radioimmunoassay at Otsuka Assay Laboratories, Otsuka Pharmaceutical Co. Ltd., Japan. The intra-assay coefficients of variation for ACTH assay were 4.4 and 1.4% at the mean concentration of
97
15 min (#) for practice, but the data were not used for ana-
43.7 and 107.5 pg/ml, respectively. The inter-assay coefficients of variation for ACTH were 8.8 and 3.4% at the mean concentration of 42.5 and 106.0 pg/ml, respectively. The intra-assay coefficients of variation for cortisol were 20.0 and 11.6% at the mean concentration of 4.00 and 11.03 mg/dl, respectively. The inter-assay coefficients of variation were 2.5 and 2.6% at the mean concentration of 5.63 and 13.56 mg/dl, respectively. The detection limit of ACTH and cortisol assays was 4.0 pg/ ml and 1.0 mg/dl, respectively.
2.5. Statistical analysis All data were subjected to statistical analysis after baseline subtraction. Mean PR, SBP, DBP, SST, and SCL were calculated for each of the five registration periods: the 3-min registration at baseline (for 3 min till the second blood draw), the 3-min registrations during 0–3 min (TASK-1), 6–9 min (TASK-2), and 12–15 min (TASK-3) after the initiation of stressor, and the 3-min registration during recovery (POST; 3 min till the fourth blood draw) after the termination of stressor. Values for PR, SBP and DBP underwent Z-transformation [(measured value — mean value at baseline)/standard deviation at baseline], and values for SCL square root transformation. The response during each registration period was defined as the mean value during the given period minus the mean value during the baseline period. Likewise, the hormonal and psychological responses, for which raw values were used, were as the mean value at each measurement point minus the mean value at the baseline (‘pre’ for hormones and ‘BASE’ for psychological testing).
98
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 2. (a) Variations in the mean depressed mood score after stress. & Mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK > POST-1**, POST-2**. TASK: CP < control**. **P< 0.01. (b) Variations in the mean tension and excitement score after stress. & mental arithmetic (MA); & cold pressor (CP); * control. CP: TASK > POST-1**, POST-2**. TASK: CP > MA*, control**. *P<0.05; **P<0.01. (c) Variations in the mean refreshing mood score after stress. & Mental arithmetic (MA); ^ cold pressor (CP); * control. MA: TASK**, POST-1** > POST-2. CP: TASK**, POST-1** > POST-2. **P <0.01.
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Main effects of group and time and their interaction were analyzed by means of two-way ANOVA followed by Tukey’s HSD test, using the STATISTICA software release 4.1 J. Correlations between hormonal responses (15 min) and mental status (TASK) as well as autonomic responses (POST) were analyzed by Spearman’s rank correlation coefficient, using StatView version 5.0. The level of significance was defined as 5%. Standard errors of the mean at measurement points are expressed by error bars in the graphs.
99
3. Results 3.1. Subjective reports of mental status For depressive mood there was a significant time effect [F(2, 42)=5.42, P=0.008] and a significant grouptime interaction [F(4, 42)=4.85, P=0.003], without any significant group effect. The depression score in the CP group, which was significantly higher only at TASK than in the control group, significantly
Fig. 3. (a) Variations in the mean pulse rate after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. MA: TASK-1**, TASK-2** > POST; TASK-1 > TASK-3*. CP: TASK-1**, TASK-2**, TASK-3** > POST. TASK-1**, TASK-2**, TASK-3*: MA>control. *P<0.05; **P< 0.01. (b) Variations in the mean systolic blood pressure after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK-1 < TASK-2**, TASK-3**. TASK-2**, TASK-3*: CP > control. POST: CP > MA**. *P<0.05; **P <0.01. (c) Variations in the mean diastolic blood pressure after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. CP: TASK-1
100
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
Fig. 3. (continued).
decreased at POST-1 and remained at the same level at POST-2 (Fig. 2a). The same score for the MA group was identical to that of the controls at any point examined (Fig. 2a). For tension and excitement there was a significant time effect [F(2, 42)=18.77, P=0.000], a significant grouptime interaction [F(4, 42)=5.49, P=0.001], but no significant group effect. The same score in the CP group was significantly higher at TASK than in the MA group and in the controls, significantly decreased at POST-1, and remained at the same level at POST-2 (Fig. 2b). For refreshing mood, there was a significant time effect [F(2, 42)=36.29, P=0.000] as well as a significant grouptime interaction [F(4, 42)=2.9, P=0.032], but no significant group effect. In both the CP and MA groups, whose scores were identical to those of controls at any measurement point, the same score significantly dropped at POST-2 compared to both TASK and POST-1 (Fig. 2c). For anxious mood
and fatigue, none of the group effect, time effect and their interaction were significant. 3.2. Autonomic variables For PR there was a significant time effect [F(3, 63)=33.83, P=0.000] as well as a significant grouptime interaction [F(6, 63)=3.70, P=0.003], without any significant group effect. In both the MA and CP groups, PR was significantly higher at TASK-1 compared to the controls, and significantly decreased with time (Fig. 3a). The PR in the MA group remained higher at TASK-2 and 3 than in controls (Fig. 3a). For SBP there was a significant time effect [F(3, 63)=8.84, P=0.000] and a significant grouptime interaction [F(6, 63)=3.42, P=0.005], but no significant group effect. In the CP group, SBP was elevated at TASK-2 and 3 compared to TASK-1, and also remained higher
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
101
Fig. 4. (a) Variations in the mean plasma ACTH concentration after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control. (b) Variations in the mean plasma cortisol concentration after stress. & mental arithmetic (MA); ^ cold pressor (CP); * control.
than in controls at TASK-2, 3, and POST (Fig. 3b). In the MA group there was no significant change in time course and in comparison to controls (Fig. 3b). For DBP there was a significant time effect [F(3, 63)=9.98, P=0.000] and a significant grouptime interaction [F(6, 63)=3.53, P=0.004], but no significant group effect. Similar to SBP, CP elevated the SBP at TASK-2 and 3, although the value was higher than in the controls only at TASK-2 (Fig. 3c). MA failed to produce any change in DBP, except for the significantly higher value at TASK-1 compared to controls (Fig. 3c). For SCL there was a significant group effect [F(2, 21)=3.80, P=0.039], a significant time effect [F(3, 63)=22.17, P=0.000], and a significant grouptime interaction [F(6, 63)=2.32, P=0.044]. In all three
groups, SCL significantly decreased with time, although to different degrees (Fig. 3d). The value in the MA group was significantly higher than in the controls and in the CP group at TASK-2 and 3 (Fig. 3d). For SST there was a significant time effect [F(3, 63)=10.03, P=0.000] but neither significant group effect nor grouptime interaction. SST tended to decrease with time (data not shown). 3.3. Neuroendocrine variables For ACTH there was a significant time effect [F(5, 105)=9.59, P=0.000], but neither significant group effect nor grouptime interaction. For cortisol as well, there was a significant time effect [F(5, 105)=20.91,
102
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
P=0.000] but neither significant group effect nor grouptime interaction. The plasma concentration of both hormones tended to be elevated during the period between 15 min and 60 min (Fig. 4a, b). 3.4. Correlations between neuroendocrine vs psychological and autonomic responses When the data of the CP, MA, and controls groups were combined, no significant correlation was found between mental status and ACTH as well as cortisol response upon cessation of stressors. PR was positively correlated with ACTH (rho=0.439, P=0.036) as well as cortisol (rho=0.422, P=0.043) response. SBP was positively correlated with cortisol response (rho=0.413, P=0.048), but not with ACTH response. DBP, SCL, and SST were not significantly correlated with either hormone. There was a strong positive correlation between ACTH and cortisol responses (rho=0.825, P=0.000).
4. Discussion The main finding of the current study indicates that the DEX/CRH test outcome is not confounded by a variety of acute stressors. Below, we will discuss the results with respect to each parameter examined. 4.1. Psychological responses In the present study, psychological testing revealed that CP significantly increased the scores for depressive mood and tension and excitement, which decreased to the normal levels during the recovery period, but MA failed to produce significant changes in these two scores. In our paradigm, CP may be a subjectively stronger stressor than MA. Neither stressor significantly altered the scores of refreshing mood, anxious mood, and fatigue, though the motivation score did drop with time in both stressors. This indicates that the scores of depression and tension and excitement may be the most sensitive indicators of subjective stress. 4.2. Autonomic responses For autonomic responses, CP significantly elavated PR at one registration period, SBP at two, DBP at one, but not SCL at any. PR and SCL decreased, and SBP and DBP increased with time. In contrast, MA caused the significant increase in PR at three registration periods and SCL at two, but not in SBP and DBP. Similarly to CP, PR and SCL declined with time in MA as well, although SBP and DBP remained at statistically identical levels. These results are in line with the report (Anderson et al., 1987) that MA sympathetic responses
to a stressor vary depending on the area of sympathetic innervation. The mechanism remains unclear as to how different stressors lead to different patterns of sympathetic activation. LeBlanc et al. (1979) showed that MA produced a greater increase of epinephrine than CP, while the effect of CP was greater on norepinephrine than MA. Ward et al. (1983) also demonstrated that epinephrine showed a greater increase to MA than to all the other stressors including CP. In this study, the norepinephrine response was not significantly different between CP and MA. As epinephrine mainly derives from the adrenal medulla and norepinephrine from the sympathetic nervous system, MA may activate the sympathetic-adrenal system more than CP. The different patterns in sympathetic activation may be associated with the different neuronal circuits of brain which process the stress response. ‘Systemic’ stressors are relayed directly to the paraventricular nucleus (PVN), probably via brainstem catecholaminergic projections, whereas ‘processive’ stressors appear to be channeled through limbic forebrain circuits which connect with PVN via interactions with GABA-containing neurons in the bed nucleus of stria terminalis, preoptic area, and hypothalamus (Herman and Cullinan, 1997). CP and MA correspond to ‘systemic’ and ‘processive’ stressors, respectively, and would be differentially processed in the central nervous system. Further elucidation requires information on regional brain responses to each stressor as obtained by functional brain imaging. 4.3. Neuroendocrine responses The post-DEX/CRH ACTH and cortisol responses to both CP and MA were statistically identical to those in the controls. Also, there was no significant correlation between the hormonal and psychological responses. These findings suggest that acute stress hardly affects the results of DEX/CRH test. In the past reports, the cortisol level after systemic cold exposure was increased (Wilson et al., 1970; Hiramatsu et al., 1984; Wagner et al., 1987), decreased (Golstein-Golaire et al., 1970; Leppa¨luoto et al., 1988) or unchanged (Ohno et al., 1987). Local cold pressor as used in the present study produced an enhanced cortisol response (Hiramatsu et al., 1984; Berger et al., 1987). After MA, cortisol was increased (Berger et al., 1987; Jørgensen et al., 1990) or unchanged (Cacioppo et al., 1995). These inconsistent results may reflect the differences in experimental paradigm as well as the subtlety of hormonal responses. Thus, in the DEX/CRH test, the effects of exogenous DEX and CRH may override the subtle alterations in HPA axis fuctions caused by stressors. We had to modify the original time course of DEX/ CRH test (Holsboer et al., 1987; Holsboer-Trachsler
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
et al., 1991) for administrative reasons. Our justification is (1) that the basal ACTH and cortisol secretions are stably low in the afternoon, when our testing was done, and (2) that the ACTH and cortisol responses to the DEX/CRH administration are nearly flat in normal subjects between 14:00 and 18:00 with the original method (e.g. Heuser et al., 1991; Holsboer-Trachsler et al., 1991; Holsboer et al., 1995). Also, we used 1.0 mg of DEX instead of the original 1.5 mg because Japanese subjects have been reported to be more susceptible to DEX suppression in DST (WHO, 1987). This dose of DEX was sufficient to produce an elevated ACTH response to the DEX/CRH test in patients with major depression (Oshima et al., 2000). As a putative mechanism underlying the ACTH and cortisol hyperresponses in combined DEX/CRH test in depressed subjects, Modell et al. (1997) have referred to the decreased function of glucocorticoid receptors (GR) regulating the vasopressin expression in the paraventricular nucleus. An escape from the GR-mediated negative feedback would result in an augmented function of vasopressin in this region, which indeed was demonstrated by Raadsheer et al. (1994) and Purba et al. (1996) using post-mortem brains of depressed patients. Our negative results in healthy volunteers may be partly explained by the lack of GR downregulation and of the resultant vasopressin hypersecretion at the level of paraventricular nucleus with the use of the short stressors that we applied. Variable correlations between hormonal and autonomic responses may be explained by the complexity of interactions regulating these two systems as well as by the above-mentioned regional variation of peripheral sympathetic responses. Again, topographical information on the brain response to stress is required for further clarification. The strong positive correlation between ACTH and cortisol responses indicates that the HPA axis function was intact in the subjects. Although the small size of the present study prevents us from drawing a definite conclusion, our data suggest that acute stress is unlikely to affect the outcome of DEX/CRH test. Therefore, augmented cortisol responses to the DEX/CRH test seen in various mental illnesses may reflect the intrinsic pathophysiology of each illness rather than stress per se.
Acknowledgements We thank Dr. Atsufumi Iida and Dr. Gerald Vogt of Emory University, Dr. Astrid C. E. Linthorst and Dr. Ayako Yamamoto of Max Planck Institute of Psychiatry, and Dr. Masahiko Mikuni of Gunma University for their warm support and helpful suggestions, and Ms. Mikie Okazaki for her excellent secretarial assistance. This study was partly supported by Health
103
Sciences Research Grants (Research on Brain Science) from the Ministry of Health and Welfare, Japan.
References Anderson EA, Wallin BG, Mark AL. Dissociation of sympathetic nerve activity in arm and leg muscle during mental stress. Hypertension 1987;9(suppl III]):III–114-III-119. Arana GW, Baldessarini RJ, Ornsteen. The dexamethasone suppression test for diagnosis and prognosis in psychiatry — commentary and review. Arch Gen Psychiatry 1985;42:1193–204. Bendarka MM, Wong GA. Effect of the stress of medical residency training on the overnight dexamethasone suppression test. Horm Metab Res 1995;27:332–4. Berger M, Bossert S, Krieg J-C, Dirlich G, Ettmeier W, Schreiber W, et al. Interindividual differences in the susceptibility of the cortisol system: an important factor for the degree of hypercortisolism in stress situations? Biol Psychiatry 1987;22:1327–39. Blouin J, Spindler E, Perez E, Blouin A, Hotz S, Hakkaku J. The role of stress in interpreting the dexamethasone suppression test. Can J Psychiatry 1992;37:724–7. Cacioppo JT, Malarkey WB, Kiecolt-Glaser JK, Uchino BN, SgoutasEmch SA, Sheridan JF, et al. Heterogeneity in neuroendocrine and immune responses to brief psychological stressors as a function of autonomic cardiac activation. Psychosom Med 1995;57:154–64. Carroll BJ, Feinberg M, Greden JF, Tarika J, Albala AA, Haskett RF, et al. A specific laboratory test for the diagnosis of melancholia — standarzation, validation, and clinical utility. Arch Gen Psychiatry 1981;38:15–22. Ceulemans DLS, Westenberg HGM, van Praag HM. The effect of stress on the dexamethasone suppression test. Psychiatry Res 1985;14:189–95. Frecska E, Luka´cs H, Arato´ M, Mo´d L, Alfo¨ldi A, Magyar I. Dexamethasone suppression test and coping behavior in psychosocial stress. Psychiatry Res 1988;23:137–45. Golstein-Golaire J, Vanhaelst L, Bruno OD, Leclercq R, Copinschi G. Acute effects of cold on blood levels of growth hormone, cortisol, and thyrotropin in man. J Appl Physiol 1970;29:622–6. Grasser A, Mo¨ller A, Backmund H, Yassouridis A, Holsboer F. Heterogeneity of hypothalamic-pituitary-adrenal system response to a combined dexamethasone-CRH test in multiple sclerosis. Exp Clin Endocrinol 1996;104:31–7. Herman JP, Cullinan WE. Neurocircuitry of stress: central control of the hypothalamo-pituitary-adrenocortical axis. Trends Neurosci 1997;20:78–84. Heuser IJE, Wark H-J, Keul J, Holsboer F. Hypothalamic-pituitaryadrenal axis function in elderly endurance athletes. J Clin Endocrinol Metab 1991;73:485–8. Heuser I, Yassouridis A, Holsboer F. The combined dexamethasone/ CRH test: a refined laboratory test for psychiatric disorders. J Psychiat Res 1994;28:341–56. Hiramatsu K, Yamada T, Katakura M. Acute effects of cold on blood pressure, renin-angiotensin-aldosterone system, catecholamines and adrenal steroids in man. Clin Exp Pharm Physiol 1984;11:171–9. Holsboer F, von Bardeleben U, Wiedemann K, Mu¨ller OA, Stalla GK. Serial assessment of corticotropin-releasing hormone response after dexamethasone in depression — implications for pathophysiology of DST nonsuppression. Biol Psychiatry 1987;22:228–34. Holsboer F, Lauer CJ, Schreiber W, Krieg J-C. Altered hypothalamicpituitary-adrenocortical regulation in healthy subjects at high familial risk for affective disorders. Neuroendocrinology 1995;62:340–7. Holsboer-Trachsler E, Stohler R, Hatzinger M. Repeated administration of the combined dexamethasone-human corticotropin releasing
104
A. Oshima et al. / Journal of Psychiatric Research 35 (2001) 95–104
hormone stimulation test during treatment of depression. Psychiatry Res 1991;38:163–71. Jørgensen LS, Christiansen P, Raundahl U, Østgaard S, Christensen NJ, Fenger M, et al. Autonomic response to an experimental psychological stressor in healthy subjects: measurement of sympathetic, parasympathetic, and pituitary-adrenal parameters: test-retest reliability. Scand J Clin Lab Invest 1990;50:823–9. Lammers C-H, Garcia-Borreguero D, Schmider J, Gotthardt U, Dettling M, Holsboer F, et al. Combined dexamethasone/corticotropinreleasing hormone test in patients with schizophrenia and in normal controls: II. Biol Psychiatry 1995;38:803–7. LeBlanc J, Coˆte´ J, Jobin M, Labrie A. Plasma catecholamines and cardiovascular responses to cold and mental activity. J Appl Physiol Respirat Environ Excercise Physiol 1979;47:1207–11. Leppa¨luoto J, Korhonen I, Huttunen P, Hassi J. Serum levels of thyroid and adrenal hormones, testosterone, TSH, LH, GH and prolactin in men after 2-h stay in a cold room. Acta Physiol Scand 1988;132:543–8. Modell S, Yassouridis A, Huber J, Holsboer F. Corticosteroid receptor function is decreased in depressed patients. Neuroendocrinology 1997;65:216–22. Ohno H, Yahata T, Yamashita K, Kuroshima A. Effect of acute cold exposure on ACTH and zinc concentrations in human plasma. Jap J Physiol 1987;37:749–55. Oshima A, Yamashita S, Owashi T, Murata T, Tadokoro C, Miyaoka H, et al. The differential ACTH responses to combined dexamethasone/CRH administration in major depressive and dysthymic disorders. J Psychiat Res 2000;34:325–8. Purba JS, Hoogendijk WJG, Hofman MA, Swaab DF. Increased number of vasopressin- and oxytocin-expressing neurons in the
paraventricular nucleus of the hypothalamus in depression. Arch Gen Psychiatry 1996;53:137–43. Raadsheer FC, Hoogendijk WJG, Stam FC, Tilders FJH, Swaab DF. Increased numbers of corticotropin-releasing hormone expressing neurons in the hypothalamic paraventricular nucleus of depressed patients. Neuroendocrinology 1994;60:436–44. Sakano Y, Fukui T, Kumano H, Horie H, Kawahara K, Yamamoto H, et al. Development and validation of a new mood inventory. Shinshin-Igaku 1994;34:629–36(in Japanese).. Schmider J, Lammers C-H, Gotthardt U, Dettling M, Holsboer F, Heuser IJE. Combined dexamethasone/corticotropin-releasing hormone test in acute and remitted manic patients, in acute depression, and in normal controls: I. Biol Psychiatry 1995;38:797–802. Senba E, Ueyama T. Stress-induced expression of immediate early genes in the brain and peripheral organs of the rat. Neurosci Res 1997;29:183–207. Wagner JA, Horvath SM, Kitagawa K, Bolduan NW. Comparisons of blood and urinary responses to cold exposures in young and older men and women. J Gerontol 1987;42:173–9. Ward MM, Mefford IN, Parker SD, Chesney MA, Taylor CB, Keegan DL, et al. Epinephrine and norepinephrine responses in continuously collected human plasma to a series of stressors. Psychosom Med 1983;45:471–86. Wilson O, Hedner P, Laurell S, Nosslin B, Rerup C, Rosengren E. Thyroid and adrenal response to acute cold exposure in man. J Appl Physiol 1970;28:543–8. World Health Organization. The dexamethasone suppression test in depression: a World Health Organization collaborative study. Br J Psychiatry 1987;150:459–62.