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Worry : a questionnaire and psychophysiological study/

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Davis, Maryanne (1998) Worry : a questionnaire and psychophysiological study/. PhD thesis, University of Tasmania.

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Abstract

It has been proposed that worry is a form of cognitive fear avoidance (Borkovec,
Shadick, & Hopkins, 1991). That is, individuals faced with actual or potential threat
avoid unpleasant physiological arousal by increasing their thought-based mental
activity: worry. Worry is maintained by this avoidance of arousal and in some
individuals becomes a common response to threat. The proposed mechanism by which
cognitive fear avoidance operates has been termed autonomic rigidity. Autonomic
rigidity refers to the suppression of the sympathetic nervous system that results in the
restriction of heart rate and skin conductance responses to stress observed in patients
with generalised anxiety disorder (Hoehn-Saric, McLeod, & Zimmerli, 1989).

The empirical part of this thesis consists of two sections. The first is the collection of
questionnaire data relating to worry in the Tasmanian university population. The
second section describes a series of three experiments that investigate the autonomic
rigidity hypothesis in female participants.
The first experiment aimed to investigate the autonomic rigidity hypothesis using a
worry period of one hour prior to a speaking task. Worriers (N=15) did not differ
from non-worriers (N=15) in their physiological response to this task. A possible
explanation for this result was that both groups may have engaged in productive
cognitive activity (thought) before the speaking task and therefore the physiological response of the groups was similar. Despite these results subjective reports indicated
a difference in worry activity between the groups.
Studies published after the first experiment was completed indicated that there may be
differences in both parasympathetic and sympathetic nervous system activity in
chronic worriers (Lyonfields, Borkovec, & Thayer, 1995; Thayer, Fiedman, &
Borkovec, 1996). Parasympathetic activity is indexed by measuring heart period
variability. The second experimental study compared average heart rate, heart rate
variability and skin conductance of worriers (N=32) and non-worriers (N --32) during
verbal and non-verbal thinking task and worry. Contrary to predictions, the results
were that worriers had more heart rate variability and tended to have lower average
heart rates than non-worriers. There was no evidence of a restriction in heart rate
variability for worriers. However, subjective differences in worry activity were found
as predicted.
The third experiment aimed to establish conditions similar to those where autonomic
rigidity was found in worriers. The average heart rate and heart period variability of
worriers (N=31) and non-worriers (N=31) were compared while they engaged in
relaxation, worry, and-aversive imagery. No difference was found in the pattern of
response to the tasks for worriers and non-worriers. However, relaxation resulted in
more heart period variability than worry or imagery. Subjective differences in worry
and relaxation were found as predicted.
The conclusions of this thesis were that, firstly, survey data reveals that there are
marked gender differences in the amount of worry in the University of Tasmania
population with women reporting more worry than men across a number of topics.
Secondly, the results of the three experiments demonstrate that autonomic rigidity is
not always found in worriers. Although differences in experimental conditions and
population may explain the findings, the phenomenon is harder to establish than
earlier findings imply.

Item Type: Thesis (PhD)
Keywords: Stress (Physiology), Anxiety, Worry
Copyright Holders: The Author
Additional Information:

Thesis (Ph.D.)--University of Tasmania, 1999. Includes bibliographical references

Date Deposited: 09 Dec 2014 00:04
Last Modified: 11 Mar 2016 05:55
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