Test of an Inhibitory Learning Model of Extinction in Treatment of Anxious Youth
Condition: Anxiety Disorders
MeSH terms: Anxiety Disorders
Study type: Interventional

Summary: 
      Recently, basic research conducted in adults has revealed that fear extinction, or the
      weakening of a learned fear response, may be best explained by principles of "inhibitory
      learning." New guidelines for the clinical practice of exposure therapy for anxiety disorders
      have arisen from research on inhibitory learning, but these guidelines have not yet been
      empirically tested in youth with anxiety disorders. The overall goal of this research is to
      investigate the acceptability, feasibility, and efficacy of conducting exposure therapy for
      anxiety disorders in youth according to clinical guidelines developed from basic research on
      inhibitory learning principles, using a pilot randomized controlled trial design.
    

Detailed description: 
      Exposure therapy-which involves repeatedly exposing individuals to feared situations to
      change their fear responses to and beliefs about those situations--has been a mainstay of
      treatments for anxiety disorders since it was developed in the 1950s. Today, exposure therapy
      is the most commonly-occurring treatment technique included in well-supported treatments for
      anxiety disorders, and meta-analyses have indicated that exposure is more strongly associated
      with treatment gains in anxious youth compared to non-behavioral interventions. Despite its
      effectiveness, approximately 40% of anxious youth fail to achieve clinically significant
      benefit from exposure therapy. This indicates that further research is needed regarding
      strategies for optimizing exposure therapy so that it is effective for a greater proportion
      of youth.

      There is clearly a need to optimize exposure therapy for youth, but at the same time very
      little empirical data exists regarding how exposure works or the best way to conduct
      exposures. Common wisdom about exposure, based on emotional processing theory, dictates that
      exposure works by breaking and eliminating conditioned fear responses through a process
      called habituation. This viewpoint dictates that exposure should be conducted until
      habituation occurs (i.e., until a physiological fear response reduces by at least 50%), and
      that habituation both during and between exposure sessions is necessary for improvement. As
      exposure therapy has evolved, other common practices have emerged that lack clear evidence
      supporting their efficacy. For example, it is common clinical practice to encourage youth to
      challenge their thoughts about a feared situation before and during an exposure (i.e.,
      cognitive restructuring), even though clear evidence does not exist to support this practice.
      Additionally, it is common for clinicians to create a "fear ladder" or "hierarchy" with
      patients before beginning exposures. This hierarchy typically takes the form of a
      rank-ordered list of exposures or feared stimuli from least to most difficult, and clinicians
      move up this list systematically from the easiest to most difficult items during treatment.
      Again, there is little clear evidence to support this practice.

      More recent research on fear extinction indicates that exposure therapy does not cause threat
      associations to disappear but rather leads to the formation of non-threat (i.e., inhibitory)
      associations that compete with and weaken older threat associations. The goal of exposure
      therapy, according to this model, is to strengthen these non-threat associations and weaken
      threat associations. Research on inhibitory learning has turned many of the long-standing
      exposure practices discussed in the previous paragraph on their head by providing new
      guidelines for optimizing exposure therapy. Many of these new guidelines differ significantly
      from common clinical practices and are designed to maximize learning of inhibitory
      associations. These guidelines are as follows:

        1. Design exposures that maximally violate a patient's expectations about how bad an
           outcome would be or how often it will occur. In clinical practice, an exposure that
           maximally violates expectancies is one that is terminated not when fear habituates or
           reduces by a certain amount (e.g., "What is your fear rating?") but rather when the
           patient's expectancy of a bad outcome is significantly reduced. (e.g., "What do you
           think the chances are that X will happen?).

        2. Do not instruct patients to change their thinking about a feared situation before or
           during and exposure. The principle of maximum violation of expectancies dictates that
           participants should not be encouraged to use cognitive reappraisal (e.g., strategies for
           thinking more realistically or accurately) during an exposure, as such strategies reduce
           the expectation that a negative outcome will occur and thus prevent maximum violation of
           expectancy.

        3. Introduce variability of stimuli into exposure tasks by moving up and down a fear ladder
           randomly. Inhibitory learning theory suggests that clinicians should frequently vary the
           difficulty of exposure to stimuli to create a consistently high level of emotion, which
           has been associated with superior extinction learning. This guideline means that,
           instead of moving up a fear hierarchy or ladder in a systematic way from least to most
           difficult over time, and moving on to more difficult items after habituation to easier
           ones has occurred, clinicians should design exposures that will allow patients to
           achieve variable but generally high levels of fear or anxiety over the full course of an
           exposure.

      In this study, the investigators plan to test these clinical practice guidelines derived from
      inhibitory learning against standard exposure practice. A few studies have empirically tested
      these and/or other clinical practice guidelines established based on inhibitory learning in
      clinical adult samples. However, no known studies have yet empirically tested the efficacy of
      an inhibitory learning approach to exposure therapy in youth with anxiety or other emotional
      disorders, nor have any known studies tested the acceptability or feasibility of such an
      approach. Therefore, in this study the investigators propose to conduct a small-scale, pilot
      randomized controlled trial (RCT) examining the feasibility, acceptability, and relative
      efficacy of applying an inhibitory learning approach to exposure in youth. Up to 20 youth
      will be randomized to one of two groups-standard exposure (SE) or exposure conducting
      according to inhibitory learning principles (E + IL). Given the small n for this study, the
      primary goal will be to assess feasibility and acceptability of an inhibitory learning
      approach to exposure, while establishing the efficacy of this approach relative to SE is
      exploratory. This study, along with planned larger-scale RCTs to follow, will help to inform
      clinical care guidelines for best practice of exposure therapy with anxious youth.
    

Intervention name(s): Standard Exposure; Exposure + Inhibitory Learning
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Exposure therapy conducted according to standard clinical care practices; Exposure therapy conducted according to practice recommendations based derived from research on inhibitory learning theories of fear extinction
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment