[Stress and anxiety: what are they?]

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.