روان رنجوری و اجتناب از محرک های مبهم: ایمنی بهتر از تاسف؟

Neuroticism predisposes to anxiety disorders, but the precise pathogenic mechanism is unknown. The aim of this study was to examine whether people with high neuroticism scores use a lower criterion for detecting danger in the face of ambiguous stimuli, and avoid a greater number of ambiguous stimuli than people with low neuroticism scores. Participants high and low in neuroticism were administered a differential conditioning task, in which one conditioned stimulus (CS+; colored circle) was followed by an electric shock (unconditioned stimulus; UCS), whereas another stimulus (CS−; different colored circle) was not. After this acquisition phase, degraded colored circles on a continuum between CS+ and CS− were presented and could be avoided by the participants within a latency of 1 or 5 s. Results indicated that the high neuroticism group avoided more degraded stimuli than the low neuroticism group, but only at the 5 s latency trials. The absence of differences at the 1 s latency trials suggests the involvement of a strategic process. Apparently, when confronted with ambiguous threat signals, people high in neuroticism use a better safe than sorry strategy. By preventing disconfirmation of irrational fears, this strategy may be involved in the development and maintenance of anxiety disorders.

Neuroticism involves a trait sensitivity to negative stimuli: individuals high in neuroticism are more likely to report distress, discomfort, and dissatisfaction over time, regardless of the situation, even in the absence of any overt or objective source of stress (Clark et al., 1994 and Watson and Clark, 1984). Neuroticism, trait anxiety, and negative affectivity show strong intercorrelations (Watson & Clark, 1984), and refer to a similar construct that is associated with affective disorders, including posttraumatic stress disorder (PTSD: Bowman, 1999, Breslau et al., 1991 and Cox et al., 2004). One of the possible explanations for this relation is that high neuroticism individuals are more reactive to adverse events than low neuroticism individuals. To test this hypothesis, prospective studies are needed in which pre-event stress symptoms are assessed. A study by Engelhard, van den Hout, and Kindt (2003) provides prospective data of a sample of pregnant women, who completed questionnaires during their early pregnancy to assess neuroticism and ‘baseline’ arousal symptoms. About 9% of the participants subsequently had a pregnancy loss. Results showed that neuroticism in early pregnancy significantly predicted PTSD symptoms one month after the loss. Yet this relationship disappeared when controlling for pre-trauma arousal symptoms: the increase in PTSD symptoms from baseline to post-pregnancy loss was similar for high and low neuroticism individuals. Thus, high neuroticism individuals did not show heightened reactivity to adverse events. These results were recently replicated in a prospective study of soldiers who were exposed to adverse events during their deployment in Iraq ( Engelhard, van den Hout, & Lommen, 2009). High neuroticism individuals reported more PTSD symptoms than low neuroticism individuals after deployment, but this was also the case before deployment; the increase in symptoms was similar for both groups. In conclusion, high neuroticism individuals were not more reactive to stressful events than low neuroticism individuals. The question is what underlying mechanism may be responsible for the heightened level of (baseline) distress in high neuroticism individuals. As stated by Ormel, Rosmalen and Farmer (2004), since neuroticism itself does not seem to have an explanatory role in the etiology of anxiety disorders, it is important to unravel cognitive and biological mechanisms that may produce high neuroticism. Many studies have focused on information processing abnormalities that may play a role in the etiology of anxiety disorders. High, compared to low, trait anxiety individuals show selective processing of both threatening and ambiguous stimuli (see Eysenck, MacLeod, & Mathews, 1987). One of the selective processes in (clinical) anxiety includes attentional bias towards threatening stimuli (Bar-Haim, Lamy, Pergamin, Bakermans-Kranenburg, & van IJzendoorn, 2007). Selective attention may lead to excessive processing of minor threats in daily life, resulting in anxiety even in conditions that are innocuous (Watson & Clark, 1984). Furthermore, high (trait) anxiety is associated with interpretation biases, which refers to the tendency to interpret ambiguous stimuli as threatening (Calvo and Castillo, 2001 and Eysenck et al., 1987), and judgmental bias, the tendency to overestimate the likelihood of negative outcomes and their costs (Butler and Mathews, 1983 and Eysenck and Derakshan, 1997). These findings suggest that high trait anxious individuals may use a lower decision criterion to detect danger in potentially threatening situations. In terms of the signal detection theory, they may be reluctant to miss a danger-signal, but willing to accept a false alarm. As everyday life involves many uncertain situations, such a better safe than sorry strategy should cause many false alarms. Especially if false alarms are followed by avoidance or escape, the inaccuracy of the alarm will not be detected, and this may help to explain why negativity is so persistent. The aim of this study was to investigate whether high compared to low neuroticism individuals avoid a greater number of ambiguous stimuli. Although several studies have focused on processing of ambiguous stimuli in high trait anxiety, studies that used a behavioral outcome variable such as avoidance of potentially threatening stimuli are scant. Moreover, most studies used stimuli of which ambiguity was assumed, and not established. To withstand these problems, this study uses a de novo conditioning task (based on Orr et al., 2000). In this task, two different neutral, conditioned stimuli (CS; i.e., colored circles) are presented in random order. In an acquisition phase, one stimulus (CS+) is always followed by an aversive, unconditioned stimulus (UCS; i.e., a mild electric shock), the other stimulus (CS−) is not. After a few presentations, a person generally learns that the CS+ predicts the UCS, and the CS− predicts the absence of the UCS. So in this phase, both a threat and a non-threat signal are learned. Following the acquisition phase, we did not immediately use an extinction phase, but introduced an ‘avoidance’ phase, that included degraded stimuli, with different color values on a spectrum between CS+ and CS− (see Fig. 1). In this phase, a potential UCS could be avoided by pushing the spacebar before the offset of the stimulus. Full-size image (8 K)