Fear extinction in anxiety patients Comparing the different fear responses of anxiety patients and healthy controls and assessing the predictive value of fear extinction on exposure therapy treatment outcome.
Summary
Fear conditioning is often used in research to study which
processes are involved in the extinction of fear.
Comparing the fear extinction abilities of anxiety patients
with healthy controls can enhance knowledge in how to
treat anxiety disorders and comparing an anxiety
patient’s fear extinction before and after treatment can
give valuable insight into the predictive value of fear
extinction. A total of 135 participants, of which 70 were
anxiety patients and 65 were healthy controls,
participated in a fear conditioning experiment containing
five phases; the habituation, uninstructed acquisition,
instructed acquisition, uninstructed extinction and
instructed extinction phase. Of those anxiety patients, 13
participated in the follow-up measurements. During each
phase, pictures of two neutral faces served as either a
danger cue (CS+) or a safety cue (CS-). During the
acquisition phases of the conditioning task, an electric
shock (US) was only administered after the CS+ was
displayed. During the instructed phases, the participants
were informed about the CS-US relationship. The
subjective anxiety scores and the expectancy of a shock
scores were measured using a VAS scale (0-100) and the
objective anxiety was measured using startle responses
that were provoked by aversive noises. Results
demonstrate that anxiety patients show stronger fear
responses to the CS+ and CS- than the control group in
the extinction phases. There were no significant
differences in how well both groups could discriminate
the CS+ and the CS-. Finally, explorative studies
demonstrated that anxiety patients had lower fearresponses
at their post-treatment measurement in
comparison with their pre-treatment measurements.
Future research could focus on using fear-relevant
stimuli, the use of verbal instructions or the use of Dcycloserine
as an enhancer of fear extinction. It is
important to further investigate the fear extinction
process, because it is closely related to exposure therapy
and could be of predictive value for treatment outcome.