Week 6: Social Anxiety Disorder
Craske (2015) – Optimizing exposure therapy for anxiety disorders: an inhibitory
learning and inhibitory regulation approach
Forms of exposure
Exposure therapy: repeated, systematic exposure to cues that are feared, avoided, or endured
with dread.
In vivo exposure: exposure to actual objects, events, or situations
Imaginal exposure: exposure to traumatic memories, catastrophic images, or obsessional
thoughts.
Interoceptive exposure: exposure to bodily sensations
Although exposure therapy is proven to be highly effective, it’s not effective for everyone. For example,
a number of individuals refuse to begin exposure therapy, or fail to complete treatment (up to 30%).
Also, approximately 50% fail to achieve clinically significant improvement with CBT for anxiety disorders,
and 19-62% show a return of fear to particular targets of exposure therapy.
Mechanisms of exposure therapy: inhibitory model of extinction
Habituation: Reducing the response strength with repeated stimulus presentations.
Fear and physiological arousal most often decline within and across exposure occasions.
This is emphasized by the emotional processing theory which states that within-session
habituation (i.e., fear reduction from initial activation or peak fear to end of exposure) is a
precursor to between session-habituation (i.e., fear reduction from one exposure session to the
next) and long-term cognitive correction.
Clinicians are typically trained to use the initial elevation of fear followed by within- and
between-session reductions of fear as a sign of treatment success, and to continue an
exposure trial until fear declines by at least 50% of initial levels. However, evidence suggests
that the amount by which fear declines from the beginning to end of an exposure session is not
a significant marker for treatment success.
Inhibitory learning model
In response to the emotional processing theory, the inhibitory learning model was proposed. Which
states that inhibitory learning is central to extinction, although mechanisms such as habituation may
also play a role.
The idea of the inhibitory learning model is that the original CS-US association learned during threat
conditioning is not erased during extinction, but rather is left intact as a new, secondary inhibitory
learning about the CS-US. More specifically, after extinction, the CS possesses 2 meanings: its original
excitatory meaning (CS-US) as well as an additional inhibitory meaning (CS-noUS). Therefore, even
though fear subsides with enough trials of the CS in the absence of the US (i.e. extinction), retention of
at least part of the original association can be uncovered by various procedures, with each one
showing a continuing effect of the original excitatory association:
Conditional fear shows spontaneous recovery: the strength of the CR increases in
proportion to the amount of time between the end of extinction training and retest.
, Renewal of conditioned fear: this occurs if the surrounding context is changed between
extinction and retest. Meaning that extinction effects are specific to the context in which
extinction occurs (=context specificity).
Reinstatement of conditional fear: This occurs if unsignaled (or unpaired) US presentations
occur between extinction and retest. So, confrontation with the US without the CS being there.
Example: you were fearful (got a panic attack) in the elevator, then you had therapy and
overcame this fear. Later you get a panic attack in the supermarket, and this made the fear for
elevators returns as well.
Rapid acquisition: If the CS-US pairings are repeated following extinction. So, experiencing
the same CS-US again
Example: being bitten by a dog again.
Which of the two expectancies (CS-US/CS-NoUS) will be activated?
This depends on several factors:
Time of interval
Lengthy intervals of time since the completion of exposure therapy will give preference to the
original threat expectancy, in line with spontaneous recovery.
Example: a patient whose fear of air travel significantly reduces by the end of treatment is likely
to report a return in their fear of flying if they do not continue to practice air travel once
treatment is completed.
Context in which the new association (CS-NoUS) is learned
If exposure therapy is completed in one or only a limited number of contexts (such as in the
presence of a therapist, or always immediately preceding or following a therapy session), the
original threat expectancy memory is likely to be activated when the phobic stimulus is
subsequently encountered in a different context (such as when alone or when unrelated to a
therapy session).
Unpredicted adverse events following exposure therapy.
These can reactive the original threat expectancy for a give stimulus, depending on context.
Example: fear of asking questions in work meetings may resurge after being criticized