[Study of the stress response: role of anxiety, cortisol and DHEAs]. / Etude de la réponse de stress: rôle de l'anxiété, du cortisol et du DHEAs.

AIM OF THE STUDY: Several studies have exhibited the psychological processes that are implied in the stress response and have shown, according to Selye's research, the participation of the hypothalamic-pituitary-adrenal axis and the major role of cortisol. The possible action of another adrenal steroïd, dehydroepiandrosterone (DHEA), is increasingly documented. The beneficial effect of the latter and his antistress role would be related to an antagonistic action to that of cortisol. The aim of our study was, first to assess biological and psychological aspects of the stress response, then to define the relationships that exist between these two processes. POPULATION AND METHODOLOGY: 40 subjects (21 women) aged 42 +/- 12 years, who consulted within a clinic of stress (CITES Prevert, Liege, Belgium) were studied. They all felt stressed but, according to DSM IV, were without mental disorders and drug free when examined. Subjects were asked to accomplish simple cognitive tasks: 1 - to distinguish two different auditory stimulations. The first one was a high-pitched sound of 1 470 Hz, which was presented unfrequently (20%). The second one, a low frequency tone of 800 Hz, was presented more frequently (80%). The interval between both stimuli was 1 s. The subject had to press a button when the rare stimulus was recognized. 2 - to extinguish a light after a warning tone of 64 dB, 50 ms and 1 000 Hz. The light, which followed one second later the tone, consisted of a series of flashes of 18 c/s that the subject had to stop by pressing a button. The purpose of this second procedure was that the subject was warned and had to prepare and anticipate the most rapid response. After that, subjects were submitted to self-evaluation psychological tests. The impact of psychosocial factors was assessed by Amiel-Lebigre life events questionnaire. Personality features and emotional response (state anxiety, related to experimental situation) were assessed by Spielberger inventory (STAI: State and Trait Anxiety Inventory). Psychological tests are practised immediately after experimental situation. Cortisol and DHEAs (dehydroepiandrosterone sulfate) were measured in blood samples taken before (t1) and after (t2) the experimental test. Cortisol was measured by radio-immunology and expressed as ng/ml of plasma. DHEAs was measured by radio-immunoassay and expressed as g/liter of plasma. RESULTS AND DISCUSSION: The majority of subjects displayed high scores of trait anxiety (37 subjects had a score>42) and life events impact (35 subjects had a score>200). These data confirmed that the subjects were fragile and were obviously stressed. In response to the cognitive tasks, that constituted for each subject a new event with which it was necessary to cope, 25 subjects exhibited high level of state anxiety (score>42) and an increase of cortisol plasmatic concentrations occurred solely in 11 persons. Ten among them were in the group of subjects which displayed a score of state anxiety>42 (p=0,0223, Chi square). Base on these data three types of stress response were identified: 1 - the experimental situation was experienced without anxiety ( psychological silence ) and without any increase in cortisol level ( biological silence ). There was no stress and these subjects were, despite their vulnerability, close to a normal health state . 2 - high emotional reaction (high level of state anxiety) was observed. This response reveals a psychological vulnerability that can be considered as the expression of a consecutive psychological distress induced by a threatening experimental situation. There were no biological manifestations ( biological silence ). 3 - high state anxiety and increased plasma cortisol levels were observed. The corresponding subjects were obviously more vulnerable. CONCLUSION: These results allow us to propose that the emergence of state anxiety is the first stress response and the primary protest . Up to a certain level, a plateau level, anxiety remains stable. Then, nature of the stress response changes and takes a biological aspect. Increased of cortisol plasma levels, the secondary protest , is observed and gives evidence of an intensified and sustained stress response. Such a gradual phenomenon is particularly reported in elevated psychological distress which is associated with loss of control. It is important to note that identical scores of state anxiety (Mann Whitney test) were observed in anxious subjects with or without rise of plasma cortisol levels. DHEAs was also implied in the stress response. The enhancement of plasma levels of DHEAs were dependent on cortisol, as shown by the close correlation between both hormones (r=0,433, p=0,0033, Spearman test). The hypothesis of an antagonism between these two hormones is based on the fact that DHEAs opposes the action of cortisol and exerts a true anticortisol effect. This antagonism might be related to a competition in their synthesis and release by the adrenal gland. In the present case, high level of anxiety (state and trait) was associated with an increase of cortisol, while low level (of anxiety) was related to an exclusive rise of DHEAs. Intermediate anxious score was observed in subjects who showed increases of both cortisol and DHEAs (p=0,0225, Kruskall Wallis test). Furthermore, a close relationship (negative correlation: Spearman test), was observed between increases in DHEAS and scores of state anxiety (r=- 0,382, p=0,06) and trait anxiety (r=- 0,0097, p=0,527). This means that the worriness and the underlying anxious ruminations and negative anticipations, which characterize trait anxiety, were less important in subjects who increased plasma DHEAs levels. In addition, emotional tension and uneasiness, which accompanies state anxiety, were also less marked. There are no studies reporting a relation between DHEA(s) and state or trait anxiety. Nevertheless, many authors have proposed a beneficial action of DHEA on the feeling of well-being. This beneficial role could be related to a double action of DHEA: a direct effect provided by its transformation into sexual hormones, an indirect one mediated by its competition with cortisol, of which the synthesis and consequently the activity decrease.

[A study of endogenous evoked potentials (P300 and CNV) in retired patients]. / Une étude des potentiels évoqués endogènes (P300, VCN), chez le sujet du troisième âge.

Endogenous evoked potentials of two types (CNV and P300 complexes) as well as their respective reaction times were recorded in 29 elderly, active subjects (15 men and 14 women) between 60 and 84 years of age. Our subjects also passed anxiety, depression and cognitive scales. The different results were then analyzed in relation with each other and in relation with age and sex. No age-related differences were found in the principal elements measured in the P300 complex, but several elements of the CNV complex were clearly shown to be age-sensitive. Sex-related differences were found in the N2 and P3a potentials. CNV morphology (Tecce type A) and cognitive scores were found to be related to Spielberger's anxiety-trait sub-scale. Several results also highlighted the heterogeneity of this age group. The need for complementary studies in this age group is then discussed with the hope that neurophysiology can become a useful tool in psychogeriatrics.

[Stress and anxiety: what are they?]. / Stress et anxiété: de quoi s'agit-il?

Although anxiety and stress were two distinguished concepts, they were used confusedly by medical and psychological talks. Whereas anxiety is currently a well-known psychopathological notion, stress remains blurred and unclear. The aim of the study was of course to exhibit the relationships between stress and anxiety, but also to show by which mechanisms anxiety would have a role in the stress-response modulation. Three groups of subjects, paired in age and sex, were compared: 28 paid controls (13 male) aged 37 +/- 12 years, 25 subjects (12 male) aged 38 +/- 8 who consulted in a framework of CITES Prevert (clinic of stress) but without mental disorders, and 28 subjects (13 male) aged 37 +/- 12, out-patients suffering from anxiety disorders (generalized anxiety disorders according to DSM IV). All of subjects were drug free when examined. They were submitted to auto-evaluation psychological tests: Amiel-Lebigre life events, Spielberger anxiety trait and state, Plutchik and Van Praag depression and finally Chapman anhedonia. After that, two ERPs were recorded, the P300 by using the classical "Oddball experimental paradigm" in auditive modality and the Contingent Negative Variation (CNV) by using a reaction time task with warning stimulus. A close relationships between stress and anxiety could be an evidence as showed by the positive correlations between life events and psychological data (anxiety and depression). In addition, the results displayed correlations between anxiety trait and CNV reaction time (positive correlation) and early P300 (P3a) component amplitude (negative correlation). This could support the hypothesis according to the anxiety would disturb the behavior (slow motor response) and the cognitive processes (attentional changes), and therefore would have a role in the stress-response modulation. Nevertheless, anxiety trait were not correlated to the late P300 component (P3b) amplitude, thus to controlled attention processes. Moreover P3b amplitude were reduced exclusively in subjects who suffered from anxiety disorders. This could mean that anxiety trait would not be solely involved in cognitive changes. Pathological states, as anxiety disorders, could involve another logic of the mental functioning. These results will be discussed according to the cognitive psychology and psychophysiology knowledges.

[Stress, anxiety and and event related potentials]. / Stress, anxiété et potentiels liés aux événements.

Our aim was to study the relationships between stress and anxiety with both psychological and neurophysiological (Events Related Potentials: CNV and P300) methods. The study was divided into 2 parts. In the first part, the research was carried out among 32 out-patients suffering from anxiety disorders (generalized anxiety disorders) according to DSM IV. All of them were drug free and displayed scores higher than 45 on the Spielberger Anxiety State and Trait Scale. They were compared to 40 controls paired in age and sex. The 2 groups displayed a score higher than 200 on the Amiel-Lebigre Life Events scale. In the second part, the control subjects were divided into 2 sub-groups The first one displayed scores higher than 45 (anxious controls) on the Spielberger Anxiety-State Scale while the second one displayed scores lower than 45 (non anxious controls). Two ERPs were recorded, the P300 by using the classical "Oddball" experimental paradigm in auditive modality and the Contingent Negative Variation (CNV) by using a reaction time task with warning stimulus. The results showed not only clear differences between the subjects who suffered from anxiety and the controls but also showed opposite results between anxious out-patients (anxiety disorders) and anxious controls. The non anxious controls were intermediate. While the outpatients showed a decreased P300, the group of anxious control showed an increase of this potential. The first one displayed a CNV/M1 (contingent negativity variation/early part) increase and a longest reaction time, while the second one exhibit an early CNV decrease and normally reaction time. It appears that the stress response expressed itself differently according to the psychological state and the stress situation. The behavioral and neurophysiological data will be discussed in the framework of cognitive, behavioral and psychophysiological theories.