The general idea is that experiencing the stimuli without (1) a feared outcome occurring, and/or (2) responding fearfully through fight/flight or safety behaviors diminishes the cognitive/neurological link between the stimuli and danger. Over time, the fear progressively decreases until it is minimal or even eliminated.
The problem with this scenario is that it requires the client to actually feel all of their fear and anxiety...and they have probably come to therapy hoping not to feel these feelings! It requires significant courage, trust in the therapist, and belief that the end result will be worth the discomfort. It also requires that the costs of living with the anxiety outweigh the discomfort of treatment.
However, given that these conditions are met, and the client agrees to exposure, the therapist has to decide between two competing protocols:
In flooding, the client is exposed to the object of intense fear, while preventing avoidance or other safety behaviors (hence the technical name, Exposure and Response Prevention), until the fear subsides. Since a discrete episode of anxiety is time-limited, the fear does in fact dissipate over time, which in turn provides new experience as a foundation for cognitive and behavioral change.
2) Systematic Desensitization
While flooding dives right in with exposure to intensely feared stimuli, systematic desensitization eases clients in more gradually. Therapist and client work together to create a hierarchy (gradated list) of anxiety-provoking stimuli. Then, treatment starts with exposure to something that produces mild anxiety. Once the stimuli no longer produces anxiety, treatment progresses one step up the hierarchy to something slightly more fear-producing.
Flooding produces more dramatic results in a shorter period of time, but is also more distressing than systematic desensitization. In contrast, systematic desensitization takes much longer to get to the source of anxiety that is causing the client the most distress. However, it also gives the client the opportunity to gain confidence and mastery as they overcome less intense fears, and demonstrates that the approach is effective before asking them to confront more intense fears.
Given these relative strengths and weaknesses, which do you prefer? Are there situations in which one is preferable to the other? How do your clients respond?